Keysight 8902A Measuring Receiver Quick Start Guide
Below you will find brief information for Measuring Receiver 8902A. This document provides information about the Agilent Technologies 8902A Measuring Receiver, including its features, and applications. It covers topics such as RF power, frequency, modulation, and audio measurements. The guide also includes operating instructions.
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Dear Customer,
As of November 1, 1999, four of Hewlett-Packard’s businesses, test and measurement, semiconductor products, health care solutions, and chemical analysis became a new company,
Agilent Technologies. Now, many of your Hewlett-Packard products and services are in the care of
Agilent Technologies.
At Agilent Technologies, we are working diligently to make this transition as smooth as possible for you. However, as a result of this transition, the products and related documentation contained in this shipment may be labeled with either the Hewlett-Packard name and logo, the Agilent Technologies name and logo, or a combination of both. Information in this package may refer to Hewlett-Packard
(HP), but applies to your Agilent Technologies product. Hewlett-Packard and Agilent branded products with the same model number are interchangeable.
Whatever logo you see, the information, products, and services come from the same reliable source.
If you have questions about Agilent Technologies products and services, please visit our website at http://www.agilent.com
.
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Q U I C K R E F E R E N C E
G U I D F
HP 8902A
RECEIVER
8902A Operation and Calibration Manual
Part Number 08902-90029
HEWLETT
PACKARD
SENSOR MODULE
AUDIO AVO
<VI
\
B
IF PEAK
DETECTOR
Tuoy
DlSTWTlDN
ANALYZER
-
AUDIO WS
DETECTOR
CHANNEL
FILTERS
IF Ws
E T E C T W
]zHDIESJh
1
COUNTER
(OPTION
SERIES
038
ONLY)
ERROR MESSACE
DISABLE
VOLTABE-TO-TIME
CONVERTER
\
RF Attenuation (dB)
0 10 20 30 40
RF Gain (dB)
50 24 14
AUTO’
1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9
AM
Slow
>
20 Hz
6.0
Except Tuned RF Level
AM
Fast
>
1 kHz
6.1
Off
6.2
2. Audio Range
Modulation
AM ("10, pk)
@M (rad, pk)
Auto
2.0
I
Detector
Pk, Ave, RMS
0.4 4
2.4 2.1 (2.4) 2.2
400
I
400
2.3
* Divide-by-10 with 750 ps FM DE-EMPHASIS and PRE-DISPLAY.
I
I
IF FREQ
I I
Wide Filter
I I
Auto
I I
2.5 MHz
Narrow Filter
4 I
I
455 kHz
Bandwidth
200
30 kHz Bandwidth kHz
[ 1.5 MHz
I
2.5 M a
Narrow Filter Out
1
RF HP Filter Out
RF HP Filter In
3.0 3.6
3.8
3.5
3.7
3.1
3.3
3.2
3.4
7. RF Frequency Resolution
AUTO
7.0
10 Hz
7.1
100 Hz
7.2
1 kHz
7.3
1 Hz
7.4
8. Error Message Disable and Enable
I
Disable Errors
01
02 02
03 03
01
02 02
03 03
04 04 04 04
I
All
Errors
Enabled
9. IF Gain
I
Detector
Measurement
Averaging Time@)
I
IFSvnchronous
AUTO
I
IFAveraae
1
10 1 0.1 AUTO 10 1 0.1
70. RF Power Range
4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7
AUTO #I
10.0 10.1
5. Audio Detector Response
Audio Peak Detector Response and RMS Detector Digital
Averaging Response:
I
Fast
I
Slow
77. Previous Ratio
-1
#2
10.2
#3
10.3
#4
10.4
#5
10.5
72/73. Calibration FM, AM
Computed
Residual
Measured
Display Peak FM
12.0
12.1
12.2
Display Peak AM
13.0
13.1
13.2
74. Limit
14.0
14.9
Disable
Display limit status: Lower limit status. Upper (O=disabled,
1 =enabled).
Lower Limit Upper Limit
Set to Ratio
Reference
Enable
Display
Display
Measurement Code
14.1
14.3
14.5
14.7
14.2
14.4
14.6
14.8
75. Time Base Check
15.0
15.1
Displays Error 12 if Option 002 is installed and oven is cold.
Displays 0 if Option 002 is installed and oven is warm, or if
Option 002 is not installed.
Displays 0 if internal time base is being used. Displays 1 if external time base is being used.
7 6. Calibration Factors: AM,
7
7. Calibration Factors: FM
Disable
Enable
Display
AM Cal Factor
16.0
16.1
16.2
FM Cal Factor
17.0
17.1
17.2
7
8. Tone-Burst Receiver
18." Configures instrument as a tone-burst receiver. A time delay of NN ms is inserted between detection of a carrier and unsquelching of the output at MODULATION OUTPUT/AUDIO
INPUT. Range of NN is 1 to 99 ms. If NN is 0, delay is 99 ms.
2
21. HP-lB Address
21.0 Displays HP-IB address in form AAAAAAA.TLS
AAAAAAA = binary address
T = 1 = talk only
L = 1 = listen only
S = 1 = requesting service
22. Service Request
22," A value of
NN
0 to 63 sums the weighted conditions below to set up a service request mask. The summed, weighted conditions are displayed when
NN
64.
1
2
Data Ready
HP-IB error (Cannot be disabled.)
4 Instrument error
8 Limit exceeded
16 Frequency Offset mode state change
32 Recal or Uncal
64 Read back SRQ mask
23. External LO (Option 030 Only)
23.0
23.1
23.2
Return the LO to internal.
Set the LO to external.
Display LO status: (0 = Internal, 1 = External)
24. Selective Power Measurement (Option 030 Only)
24.0 Sets the Measuring Receiver to the Selective Power Measurement
Mode.
Select
Establish dB
Display
Normalize
Noise Meas.
Wide BW IF Filter
(Adjacent-Channel, Cellular)
Narrower BW IF Filter
(Adjacent-Channel)
Narrowest BW IF Filter
(Single-Sideband Noise)
24.1
24.3
24.5
24.2
24.4
24.6 24.7
24.8
24.9
Sets the value of the noise measurement BW.
Display the value of the noise measurement BW.
25. External Attenuation
(dB)
25.2 Display attenuation value.
3
26. Set Reference
26.0
26.1
Exit attenuator measurement
Re-enter attenuator measurement
27. Frequency Offset Control
Frequency Offset Mode
Exit Re-enter
27.0 27.1
Display
External LO
Enter/Ena ble
27.2 27.3
29/30. Other Audio Measurement Modes
29.0 SINAD
30.0 EXT AUDIO RMS LEVEL
31. Tuned RF Level Noise Correction
31.0
31.1
31.2
Turn off noise correction.
Turn on noise correction.
Dipslay noise correction status (1 = Off, 0 = On).
32. dB and Frequency Resolution
32.0
32.1
32.2
Normal measurement resolution (Power: 0.01 dB resolution)
(Audio Frequencies from 100 to 250 kHz; 0.1 Hz resolution).
Increased measurement resolution (Power: 0.001 dB resolution)
(Audio Frequencies form 100 to 250 kHz; 0.1 Hz resolution).
Display measurement resolution status. (0 = normal,
1 = increased.
32.9 Tuned RF Level Measurements Using Track-Mode Tuning
1.
2.
3. If
4.
5.
Input a signal greater than -30 dBm.
Select 32.9 SPCL. using an external LO, enter the external LO frequency in
Select MHz to enter the manual tune mode.
MHz.
Step the signal generator down in amplitude and press the
CALIBRATE key whenever the RECAL annunciator is displayed.
4
33/36. Other Measurement Modes
33.0 LO FREQUENCY
34.0 IF FREQUENCY
35.0 RFLEVEL
36.0 PEAK TUNED RF LEVEL
37. Calibration Factors: RF Power
37.0
37.1
37.2
37.3
37.4
37.5
37.6
37.7
Automatic Cal Factors
Manual Cal Factors
Display Status (0 = auto, 1 = held)
*Enter frequency, cal factor
*Display table size
*Recall reference cal factor
*Recall next frequency, cal factor
*Clear Table
* Two tables are available. The table being used is determined by the status of the Frequency Offset mode (Special Function 27).
38/39. Calibration Factors Tuned RF Level
39.9
Display
Enter
RF Power
Range 1 to
38.1
39.1
Range
1 to 2
38.2
39.2
Clear all calibration factors.
Range
2 to 3
38.3
39.3
SET REF
Reference
38.4
39.4
5
6
Frequency Offset (Special Function
27).
The Frequency Offset mode allows the Measuring Receiver to keep track of frequencies involved in the down-conversion process. This frequency offset process is used in conjunction with an external mixer and Local Oscillator (LO) to extend the frequency coverage above
1300 MHz.
To enter the Frequency Offset mode:
+
LO Frequency
+
Fl
To exit the Frequency Offset mode:
To re-enter the Frequency Offset mode with the same LO frequency:
To display the external LO frequency:
Display
Code
- - or 0 MHz
To Solve an Input Problem
Adjust input signal level or change measurement sensitivity.
- - - -
Manually tune to input signal.
- - - - - -
Check tuning.
01
02
03
To Solve an Operating Problem
Decrease RF attenuation or gain.
I
Re-check operating conditions being used.
Re-check special operating conditions being used.
Increase input signal level or decrease
AM.
Press the MHz key to center IF signal in IF passband.
If problem persists, signal may be drifting.
Increase RF input attenuation.
Increase level of input signal.
Decrease RF and/or IF gain setting.
Decrease selected or increase IF gain.
RF input attenuatior
If Range Hold is being used, check range limits.
04
05
06
07
08
09
10
Decrease modulation level on input signal to within measurement range.
Increase range limit setting, Special
Function 2.N.
Increase carrier level or decrease AM depth (<go%).
Input level exceeds 7 Vrms (1 W peak).
Decrease level of input signal.
If making a TRFL measurement, also press the CLEAR key.
I
Decrease selected RF or IF gain.
If Range Hold is being used, check range limits.
Decrease modulation level on input signal.
If making a TRFL measurement, decrease level of input signal and pres
CLEAR key.
Check connection to Calibrator.
Check for Calibrator malfunction.
Adjust frequency of input signal to within measurement range, or increase measurement range.
If making a TRFL measurement, set thc input level to between 0 and -20 dBm.
Select the Frequency mode. When the instrument displays the frequency of the input signal, press the MHz key an( re-enter the TRFL mode.
I
I
I
Decrease selected RF or IF gain.
If Range Hold is being used, check range limits.
Check internal time base for malfunction (Option 002 only).
7
8
21
24
25
22
23
26
12
13
14
15
16
17
Display
Code
11
18
19
20
Operating Error Codes
To Solve an Input Problem To Solve an Operating Problem
Select linear (Watts) units, or disregard error when there is no power present at sensor input.
Key in a different ratio reference.
Wait for oven to warm for highest accuracy.
Secure connection at SENSOR input.
Remove power from power sensor input during zeroing process.
Verify that cal factors have been entered.
Increase audio signal level.
Input signal level during reference measurement must be between 1.29’ and 2.5QV.
Check selected RF or IF gain level.
(When making Ratio measurements, allow instrument to complete the reference measurement.)
Check sensor connection at RF
POWER OUTPUT port.
Increase IF gain.
Re-enter frequency within measuremen range. (In Ratio mode, a reference measurement of zero is invalid.)
Check compatibility of function(s) with selected measurement mode.
Check Special Function number and re-enter (prefix invalid).
Check Special Function number and re-enter (suffix invalid).
Invalid HP-IB code. Check function codes.
Check Special Function Compatibility with measurement.
End of RF Power calibration table. (If displayed after first attempt to read table using empty.)
37.6 SPCL, the table is
Display
Code
30
31
32
33
34
35
To Solve an Input Problem To Solve an Operating Problem
Change RF attenuation and gain or
Range Hold setting.
Calibrate RF Power measurement.
Change IF gain or Range Hold setting.
Maintain stable frequency and level during calibration.
Check SENSOR connection.
Maintain stable frequency during TRFL calibration.
Use a stable signal source for TRFL calibration.
Check RF Power calibration.
9
10
Function
MEASUREMENTS
AM
FM
@M
RF POWER
FREQ
AUDIO FREQ
AUDIO DlSTN
IF LEVEL
TUNED RF LEVEL
FREQ ERROR
DETECTORS
PEAK+
PEAK-
PEAK HOLD
AVG (RMS Calibrated)
1 kHz DlSTN
400 Hz DISTN
RMS
PEAK&/2
DISPLAYS
Display LOG Result
Display LIN Result dB EXT ATTEN
Off off dB EXT AlTEN on
RATIO
RATIO On
PREVIOUS RATIO
FILTERS
HP (High-Pass) FILTERS
50 Hz FILTER On
300 Hz FILTER On
Off
LP (Low-Pass) FILTERS Off
3 kHz FILTER On
15 kHz FILTER On
>20 kHz FILTER On
FM DE-EMPHASIS
PRE-DISPLAY Off and
FM DE-EMPHASIS Off
PRE-DISPLAY On and
FM DE-EMPHASIS On
25 PS DE-EMPHASIS
50 PS DE-EMPHASIS
75 PS DE-EMPHASIS
750 ps DE-EMPHASIS
Measuring Receiver finction to Code Summary
Code
M1
M2
M3
M4
M5 s1 s2 s3 s4 s5
HO
H1
H2
LO
L1
L2
L3
LG
LN
NO
N1
RO
R1
R2
D1
D2
D3
D4
D5
D6
D8
D9
PO
P1
P2
P3
P4
P5
CALIBRATION
CALIBRATE Off
CALIBRATE On
Yo CAL FACTOR
SET REF
ZERO
SAVE CAL
MANUAL OPERATIONS
AUTO TUNING
ENABLE ERRORS
DISABLE ERRORS
CLEAR (KEY)
BLUE KEY, CLEAR (KEY)
DISPLAY FREQ
DISPLAY INCREMENT
INPUT FREQUENCY (Hz) u Hz
Hz
TRACK Mode Off
TRACK Mode On
(Lock Mode) fi kHz
4) kHz
MHz (INPUT FREQ)
RECALL
STORE
SPECIAL FUNCTION
SPECIAL, SPECIAL mV Units p V Units
V Units
W Units
MISCELLANEOUS
MODULATION OUTPUT
AUDIO INPUT
AUTOMATIC OPERATION
Auto-Ranging (RANGE HOLD
RANGE HOLD
Identify Instrument
INSTR PRESET (same as DCL)
Trigger Off
Hold
Trigger Immediate
Trigger with Settling
Hexidecimal A
Hexidecimal
Hexidecimal
B
Hexidecimal C
D
Hexidecimal E
Hexidecimal F
Off)
Code
HU
HD
KO
K1
KU
KD
MZ
RC
TR
SP
AT
BO
B1
CL
BC
FR
FN
HZ ss
MV uv
VL
WT co c 1
CF
RF
ZR sc xo x1 x2 x3 x4 x5
A0
A1
AU
GO
G1
ID
IP
TO
T1
T2
T3
Code
ID
IP
KO
K1
KU
KD
LO
L1
L2
L3
LG
LN
A0
A1
AT
AU
BO
B1
BC co c 1
CF
CL
FR
FN
GO
G1
D1
D2
D3
D4
D5
D6
D8
D9
HO
H1
H2
HU
HD
HZ
Code to Measuring Receiver finction Summary
Function Code
MODULATION OUTPUT
AUDIO INPUT
AUTO TUNING
AUTOMATIC OPERATION
ENABLE ERRORS
DISABLE ERRORS
BLUE KEY, CLEAR (KEY)
CALIBRATE Off
CALIBRATE On
Yo
CAL FACTOR
CLEAR (KEY)
PEAK+
PEAK-
PEAK HOLD
AVG (RMS Calibrated)
1 kHz DISTN
400 Hz DISTN
RMS
PEAKf/2
DISPLAY FREQ
DISPLAY INCREMENT
Auto-Ranging (RANGE HOLD Off)
RANGE HOLD
HP (High-Pass) FILTERS Off
50 Hz FILTER On
300 Hz FILTER On
-Tr u Hz
Hz
INPUT FREQUENCY (Hz)
Identify Instrument
INSTR PRESET (same as DCL)
TRACK Mode Off (lock mode)
TRACK Mode On kHz kHz
LP (Low-Pass) FILTERS Off
3 kHz FILTER On
15 kHz FILTER On
>20 kHz FILTER On
Display LOG Result
Display LIN Result
M1
M2
M3
M4
M5
MV
MZ
NO
N1
PO
P1
TO
T1
T2
T3
TR uv
VL
WT xo x1 x2 x3 x4 x5 s1 s2 s3 s4 s5 sc
SP ss
ZR
P2
P3
P4
P5
RO
R1
R2
RC
RF
Function
AM
FM
(PM
RF POWER
FREQ mV Units
MHz (INPUT FREQ) dB EXT ATTEN Off dB EXT ATTEN On
PRE-DISPLAY Off and
FM DE-EMPHASIS Off
PRE-DISPLAY On and DE-EMPHASIS On
25 PS DE-EMPHASIS
50 PS DE-EMPHASIS
75 PS DE-EMPHASIS
750 /AS
RATIO Off
RATIO On
PREVIOUS RATIO
RECALL
SET REF
AUDIO FREQ
AUDIO DISTN
IF LEVEL
TUNED RF LEVEL
FREQ ERROR
SAVE CAL
SPECIAL FUNCTION
SPECIAL, SPECIAL
Trigger
Hold
Off
Trigger Immediate
Trigger with Settling
STORE pV Units
V Units
W Units
Hexidecimal A
Hexidecimal B
Hexidecimal C
Hexidecimal D
Hexidecimal E
Hexidecimal F
ZERO
11
12
HP 8901A
A1 (or AU)
F1 (or MZ)
F2 (or KU)
F3 (or KD)
F4 (or 24 or SP)
F5 (or 25 or SS)
K1 (or CL)
U1 (or D1)
U2 (or D2)
U3 (or D3)
U4 (or D4)
Z1 (or HZ)
22 (or HU)
23 (or HD)
M4 s4
R1
R2
4.0SP
4.1 SP
4.2SP
7.1 SP
7.2SP
9.OSP
1O.OSP
11 .OSP
11.1SP
11.3SP
15.0SP
Status
Byte
CL
D1
D2
D3
D4
HZ
HU
HD
35.0SP
36.0SP
LN, R1
LG, R1
AT, KO
AT, K1
MZ, KO
7.1 SP
7.3SP
G1
34.0SP
LN, R2
LG, R2 use "-" key
15.0SP
HP 8901A/02A Code Differences
HP 8902A Functions
AU
MZ
KU
KD
Status
Byte
AUTOMATIC OPERATION
MHz (INPUT FREQ)
4 kHz kHz
SPECIAL
SPECIAL, SPECIAL
CLEAR
PEAK+
PEAK-
PEAK HOLD
Average Detector (RMS Calibrated)
Hz INPUT FREQ u Hz
Hz
Peak RF Level
Peak Tuned RF Level
O/o
RATIO dB RATIO
Auto Tuning, low-noise lock mode
Auto Tuning, track mode
Manual Tuning, low-noise lock mol e
10 Hz frequency resolution
1000 Hz frequency resolution
Hold Setting (RANGE HOLD)
IF Frequency
O/o
PREVIOUS RATIO dB PREVIOUS RATIO
Make Ratio Reference Negative
Oven Check (returns the 8901 A)
" 0 installed, rather than doing nothing as in
Status Byte Bits "Upper Limit" (weight 8) and "Lower Limit" (weight 16) are merged together into "Limit Reached" (weight 8)
Agilent Technologies. Inc
24001 E Mission
Liberty take, WA 99019 www.agtlent.com
.
.::%;.
.
* .
!
.
.
Ag
i
t
Techno log ies
Innovating the HP Way
June 8,2000
Dear Customer,
As of November 1, 1999, four of Hewlett-Packard’s businesses, test and measurement, semiconductor products, health care solutions, and chemical analysis became a new company,
Agilent Technologies. Now, many of your Hewlett-Packard products and services are in the care of
Agilent Technologies.
At Agilent Technologies, we are working diligently to make this transition as smooth as possible you. However, as a for result of this transition, the products and related documentation contained in this shipment may be labeled with either the Hewlett-Packard name and logo, the Agilent Technologies name and logo, or a combination of both. Information in this package may refer to Hewlett-Packard
(HP), but applies to your Agilent Technologies product. Hewlett-Packard and Agilent branded products with the same model number are interchangeable.
Whatever logo you see, the information, products, and services come from the same reliable source.
If you have questions about Agilent Technologies products and services, please visit our website at http://www. agilent.com.
Sincerely,
Rebranding Team
MEASURING RECEIVER
Operation and Calibration Manual
SERIAL NUMBERS
This manual provides complete information for in- struments with serial-number prefixes:
2305A to 29148
and
all
MAJOR
changes
that
apply to your instrum rev.
01
numbers, refer to "INSTRUMENTS COVERED
THLS MANUAL" Section 1.
BY
Sixth Edition
This material may
Government pursuant to the Copyright License der the clause at be reproduced by or for the
DFARS
52.227-7013 (APR
U.S.
1988).
EAST 24001
CopyrightOHEWLETT-PACKARD COMPANY 1985
MISSION AVENUE, TAF C-34, SPOKANE, WASHINGTON, U.S.A. 99220
Operation and Calibration Manual HP Part 08902-90029
Other Documents Available:
Basic Operation and Application Guide HP Part 5953-8458
Quick Reference Guide HP Part 08902-90060
Service Manual HP Part 08902-90031
Microfiche Operation and Calibration Manual HP Part 08902-90030
Microfiche Service Manual HP Part 08902-90032 Printed in USA. :
HEWLETT
PACKARD
1
Regulatory Information
(Updated
March
1999)
Regulatory Information (Updated March 1999)
Safety Considerations
GENERAL
This product and related documentation must be reviewed for familiarization with safety markings and instructions before operation.
This product has been designed and tested in accordance
"Safety Requirements for Electronic Measuring Apparatus," and has been supplied in a safe condition. condition.
This with
IEC Publication 1010,
instruction documentation contains information and warnings which must be followed by the user to ensure safe operation and to maintain the product in a safe
SAFETY EARTH GROUND
A
uninterruptible safety earth ground must be provided from the main power source to the product input wiring terminals, power cord, or supplied power cord set.
A SYMBOLS
Indicates instrument damage can occur if indicated operating limits are exceeded.
A
Indicates hazardous voltages.
Indicates earth (ground) terminal
WARNING
A WARNING note denotes a hazard. It calls attention to a procedure, practice, or the like, which, if not correctly performed or adhered to, could result in personal injury. Do not proceed beyond a sign until the indicated conditions are
WARNING
CAUTION A CAUTION note denotes a hazard. procedure, practice, or the like, which, if not correctly performed or adhered to, could result in damage to or destruction of part or not proceed beyond an understood and met.
CAUTION
It calls attention to all an operation of the product. Do note until the indicated conditions are fully
2 Chapter 1
Regulatory information (Updated March 1999)
Safety Considerations for this Instrument
WARNING This product is a Safety Class I instrument (provided with a protective earthing ground incorporated in the power cord). The mains plug shall only be inserted in a socket outlet provided with a protective earth contact. Any interruption of the protective conductor inside or outside of the product is likely to make the product dangerous. Intentional interruption is prohibited.
Whenever it is likely that the protection has been impaired, the instrument must be made inoperative and be secured against any unintended operation.
If this instrument is to be energized via an auto transformer (for voltage reduction), make sure the common terminal is connected to the earth terminal of the power source.
If this product is not used as specified, the protection provided by the equipment could be impaired. This product must be used in a normal condition (in which all means for protection are intact) only.
No qualified personnel. To prevent electrical shock, do not remove covers.
Servicing instructions are for use by qualified personnel only. qualified to do so.
To avoid electrical shock, do not perform any servicing unless you are
The opening of covers or removal of parts while it is being opened. is likely to expose dangerous voltages. Disconnect the product from all voltage sources
The power cord is connected live to internal capacitors that my remain for 5 seconds after disconnecting the plug from its power supply.
For Continued protection against fire hazard, replace the line fuse(s) only with 250
V
fuse(s) or the same current rating and type (for example, normal blow or time delay). Do not use repaired fuses or short circuited fuseholders.
Always use the three-prong ac power cord supplied with this product. Failure to ensure adequate earth grounding by not using this cord may cause product damage.
This product is designed
Pollution Degree 2 per
INDOOR
USE for use in Installation Category I1 and
ZEC
1010
and IEC 664 respectively. FOR
This product has autoranging line voltage input, be sure the supply voltage is within the specified range.
Chapter 1 3
Regulatory Information (Updated March 1999)
To before cleaning. Use a dry cloth to clean the external case parts. from mains (line) or one slightly dampened with water
Do to clean internally.
Ventilation Requirements: When installing the product in a cabinet, the convection into and out of the product must not be restricted.
The ambient temperature (outside the cabinet) must be less than the maximum operating temperature of the product for every 100 watts dissipated in the cabinet. used.
If by 4" C the total power dissipated in the cabinet is greater than 800 watts, then forced convection must be
Product Markings
CE - the CE mark is a registered trademark of the European Community. accompanied by a year indicated the year the design was proven.
A CE mark
CSA - the CSA mark is a registered trademark of the Canadian Standards Association.
4 Chapter 1
CERTIFICATION
Hewlett-Packard Company certifies that this product met its published specifications at the time of shipment from the factoo. Hewlett-Packard further certifies that its calibration measurements are traceable to the United
States National Bureau of Standards, to the extent allowed by the Bureau’s calibration facility, and to the calibration facilities of other International Standards Organization members.
WARRANTY
This Hewlett-Packard instrument product is warranted against defects in material and workmanship for a period of one year from date of shipment. During the warranty period, Hewlett-Packard Company will at its option, either repair or replace products which prove to be defective.
For warranty service or repair, this product must be returned prepay shipping charges to to
HP and HP shall pay shipping charges a service to facility designated by HP. Buyer to shall shall pay aII shipping charges, duties, and taxes for products returned to HP from another country.
HP warrants that its software and frmware designated by HP for use with an instrument will execute its programming instructions when properly installed on that instrument. HP does not warrant that the operation of the instrument, or software, or firmware will be uninterrupted or error free.
LIMITATION
OF
WARRANTY
The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by Buyer,
Buyer-supplied software or interfacing, unauthorized modification or misuse, operation outside of the environmental specifications for the product, or improper site preparation or maintenance.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. HP SPECIFICALLY DISCLAIMS THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
EXCLUSIVE REMEDIES
THE REMEDIES
DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.
ASSISTANCE
Product maintenance agreements and other customer assistance agreements are available for Hewlett-Packard products.
For any assistance, contact your nearest Hewlett-Packard Sales and Service Office. Addresses are provided at the back of this manual.
iv
Model 8902A Safety Considerations
SAFETY CONSIDERATIONS
GENERAL
This product and related documentation must be re- viewed for familiarization with safety markings and instructions before operation.
This product is a Safety Class I instrument (provided with a protective earth terminal).
BEFORE APPLYING POWER
Verify that the product is set to match the available line voltage and the correct fuse is installed.
SAFETY EARTH GROUND
An uninterruptible safety earth ground must be pro- vided from the main power source to the product input wiring terminals, power cord, or supplied power cord set.
A
Instruction manual symbol: the product will be marked with this symbol when it is necessary for the user to refer to the instruction manual (refer to Table of Contents). f
Indicates hazardous voltages.
-
Indicates earth (ground) terminal. procedure, practice, or the like, which, if not correctly performed or adhered to, could result in personal in- jury. Do
The WARNING sign denotes a hazard. It calls attention to a not proceed beyond a WARNING sign until the indicated conditions are fully understood and met.
The CAUTION sign denotes a haz- ard. It calls attention t o an operating procedure, practice, or the like, which, if not correctly performed or adhered to, could result in dam- age to or destruction of part or all of the product. cated conditions are fully understood and met.
Do not proceed beyond a CAUTION sign until the indi-
(WARNING1
Any interruption of the protective (ground- ing) conductor (inside or outside the instru- ment) or disconnecting the protective earth terminal will cause a potential shock hazard that could result in personal injury. (Ground- ing one conductor of a two conductor outlet is not sufficient protection).
Whenever it is likely that the protection has been impaired, the instrument must be made inoperative and be secured against any unin- tended operation.
If this instrument is to be energized via an autotransformer (for voltage reduction) make sure the common terminal is connected to the earth terminal of the power source.
Servicing instructions are for use by service- trained personnel only. To avoid dangerous electric shock, do not perform any servicing unless qualified to do so.
Adjustments described in while protective covers are removed. Energy available at many points may, sult
in
personal injury. the manual are per- formed with power supplied to the
if
instrument contacted, re-
Capacitors inside the instrument may still be charged even if the instrument has been dis- connected from its source of supply.
For continued protection against fire hazard, replace the line fuse(s) only with 250V fuse(s) of the same current rating and type (for exam- ple, normal blow, time delay, etc.). Do not use repaired f u s e s or short circuited fuseholders.
Model 8902A Safety Considerations
ATTENTION
Static Sensitive
Devices
This instrument was constructed conductor devices used by static discharge. in in charge) protected environment. This is because most of the semi- this instrument are susceptible to damage
Depending on the magnitude of the charge, device substrates can be punctured or destroyed by contact static charge. The results can cause degradation of device perform- ance, early failure, or or mere proximity of a immediate destruction.
These charges are generated in numerous ways such as simple contact, separation or materials, and normal motions of persons working with static sensitive devices.
When handling or servicing equipment containing static sensitive devices, adequate precautions damage or destruction. must be taken
to
prevent device
Only those who are thoroughly familiar with industry accepted techniques for handling static sensitive devices should attempt to service circuitry with these devices.
I n all instances, measures must be taken to prevent static charge build-up on work surfaces and persons handling the devices.
For further information on ESD precautions, refer to “SPECIAL
HANDLING CONSIDERATIONS FOR STATIC SENSITIVE
DEVICES” in Section 8, Service.
V
Contents Model 8902A
Instruments Covered by This Manual
Hewlett-Packard Interface Bus (HP-IB)
Additional Equipment Information
Section 1
General Information
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section
Installation
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Detailed Operating Instructions
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modulation Measurements Contents
Additional Capabilities Contents
Section 3
Operation
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Characteristics of the Measuring Receiver
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Basic Functional Checks of the Measuring Receiver
Basic Functional Checks of the Hewlett-Packard Interface Bus (HP-IS)
. . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-71
Table of Contents . . . . . . .
Section 4
Performance Tests
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-0
Table of Contents
Section 5
Adjustments
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-0 vi
Gene1 a1 Information r-
Model 8902A
MODEL. 8902A
LINE POWER CABLE
Model 8902A General Information
Section 1
GENERAL INFORMATION
1-1. INTRODUCTION TO THIS MANUAL
The HP 8902A Operating and Service Manual is comprised of an Operation and Calibration Manual and the three volume Service Manual. These four volumes contain install, operate, test, adjust, and service the Hewlett-Packard Model all the information required
8902A Measuring Receiver. to
The information to operate and service this instrument is made available as follows: Sections 1 through
5 are contained in the Operation and Calibration Manual
Application Guide) which is
Service Manual Request Card included in this manual.
(that includes the provided with each instrument. Sections
Basic Operation and
6 through 8 are contained in the
Service Manual that is not included with the instrument but which can be obtained by mailing in the
The Measuring Receiver is shown in Figure 1-1 with all supplied accessories. These manuals document
Measuring Receivers supplied with Options 001,002,003,004, series 030 and 050.
Operation and Calibration Manual
Section 1, General Information describes the instruments documented by this manual and covers instrument description, options, accessories, specifications and other basic information. This section also contains instrument theory of operation on a simplified block diagram level.
Section 2, Installation provides information about initial inspection, preparation for use (including address selection for remote operation), and storage and shipment.
Section 3, Operation provides information about panel features and includes operating checks, and operating instructions for both local and remote operation.
Section 4, Performance Tests provides the information required
instrument against the critical specifications in Table 1-1.
to check performance of the
Section 5, Adjustments provides the information required to properly adjust the instrument.
Service Manual
Section 6, Replaceable Parts provides ordering information for all replaceable parts and assemblies.
Section 7, Instrument Changes information. provides backdating information, and retrofitting and modification
Section 8, Service provides the information required to repair the instrument.
Additional copies of the Operation and Calibration Manual or the Service Manual can be ordered separately through your nearest Hewlett-Packard office. The part numbers are listed on the title page of this manual. rev.24AUG87 1-1
General Information Model 8902A
1-2.
SPECIFICATIONS
Instrument specifications are listed in Table 1-1.
These are the performance standards, against which the instrument may be tested. Information listed in this table as or limits,
Supplemental
Characteristics, are not warranted specifications but are typical characteristics included as additional information for the user.
1-3. SAFETY CONSIDERATIONS
This product is a SafeQ Class
Measuring Receiver and all related documentation must be reviewed for familiarization with safety markings and instructions before operation. Refer beginning of this manual for a
I instrument (that is, provided with a protective earth terminal). The to the Safety Considerations summary of the safety information. page found at the
Safety information pertinent to the task at hand (installation, operation, performance testing, adjustment or service) is found throughout these manuals.
1-4. RECOMMENDED TEST EQUIPMENT
lists the test equipment and accessories recommended servicing the Measuring Receiver. for use in testing, adjusting, and
If any of the recommended equipment is unavailable, instruments
with equivalent minimum speci&ations may be substituted. Table
equipment listings. Table the Service Accessory Kit, HP 08901-60287.
also includes some alternate
1-3 lists a number of accessories required in addition to those contained in
1-5. INSTRUMENTS COVERED
BY
THIS MANUAL
Options
Electrical options 001,002,003,004, series 030, 050, in these manuals. The differences are noted under paragraph
Parts, and in the schematic diagrams in Section 8. and various mechanical options are documented
1-8, Options, in Table 6-3, Replaceable
Serial Numbers
Attached pages. to the instrument is a serial number plate. The serial number is in the form that is unique to each instrument. The contents of these manuals apply directly to
1234A00123.
The first four digits and the letter are the serial prefix. The last five digits form the sequential suffix instruments having the same serial number prefix(es) as listed under SERIAL NUMBERS on the respective manual title
For information concerning a serial number prefix not listed on the title page or in the Manual Changes supplement, contact your nearest Hewlett-Packard office.
1-6.
DOCUMENTATION UPDATING
An instrument manufactured after the printing of these manuals may have a serial number prefix that is not listed on the manual title page. Having a serial number prefix that is greater than that shown on the title page indicates that the instrument is slightly different from those documented in the manual.
In this case, your manual is provided with updating information to make it as current as possible.
This updating information includes any hardware or software changes that have occurred as well corrections to the documentation. as
A Description of the Manual Update Packet
A Manual Update packet consists of replacement and addition pages which should be incorporated in your manual to bring it up to date.
1-2 rev.24A UG8 7
Model 8902A General Information
Signing Up for the Documentation Update Service
Hewlett-Packard offers a Documentation Update Service that will provide you with further updates and changes as they become available. If you have not received update information that matches the serial number of your instrument, you can receive this information through the Update Service.
If you operate or service instruments with different serial prefixes, we strongly recommend that you join this service immediately to ensure that your manual is kept current. For more information, refer to the Documentation Update Service reply card included in this manual or contact:
Hewlett-Packard Company
Technical Writing Department
24001 E. Mission-TAF C-34
Spokane, WA 99220
(509) 922-400 1
Also, if you join the update service, you can indicate whether you choose to be contacted in the future about the quality of the documentation you receive. We are trying to improve the documentation we provide and periodically survey customers as to their expectations of the manuals.
1-7. HEWLETT-PACKARD INTERFACE BUS (HP-IB)
Compatibility
The Measuring Receiver’s capabilities are defined by the following interface functions: SH 1, AH 1,
T5, TEO, L3, LEO, SR1, RL1, PPO, DCl, DTI, CO. The Measuring Receiver interfaces with the bus via open-collector TTL circuitry. An explanation of the compatibility code may be found in IEEE
Standard 488- 1978, IEEE Standard and Digital Interjace jor Programmable Instrirmentalion or the identical ANSI Standard MCl. 1.
For more detailed information relating to programmable control of the Measuring Receiver, refer to
Rcmotc Operalion, Hcwlctf-Packard Inter-ace Bits in Section 3 of this Opcraling Information manual.
Selecting the HP-IB Address
The HP-IB address switches are located within the Measuring Receiver. The switches represent a five-bit binary number. This number represents the talk and listen address characters which controller must generate. In addition, two more switches allow the Measuring Receiver to be set to talk only or to listen only. A table in Section 2 shows all HP-IB talk and listen addresses. Refer to
Sclcc-fion in Section 2 of this Opcration and Calihration manual.
HP-Ill A ddrm
1-8. ADDITIONAL EQUIPMENT INFORMATION
Options
Options are variations on the standard instrument which can be ordered during the purchase. The following list defines all currently available options. Refer to Electrical Eyiripmcnt A vailahlc in this section for retrofit part numbers that can be ordered after the purchase.
Option 001 This option provides rear-panel (instead of front-panel) connections for
BRATION OUTPUTS.
RF INPUT,
SENSOR input, MODULATION OUTPUT/AUDIO INPUT, and AM/FM and RF POWER CALI-
Option 002 This option provides a high-stability (1 x lO-”day) internal reference oscillator in place of the standard reference oscillator. In addition, a 10 MHz time base output is provided on the rear panel.
1-3
General Information Model 8902A
Option 003 This option provides both an output for the internal local oscillator for an external local oscillator signal. Both connections are located on the provided automatically with option 030 series instruments.) signal and an input rear panel. (This output is
Option 004 This option frequencies greater than allows
66 Hz is restricted to less
than
126.5
48
Vac line input. to 400
Option 030 The High Selectivity Measurement option provides the capability sideband carrier noise (AM or phase) quickly and accurately up to 1.3 GHz to measure single- with an external LO. (An output for the internal local oscillator and an input for an external local oscillator signal is provided with these options.) This option is ordered with one of the following filter options:
Option 032 This option provides a 12.5 kHz adjacent channel filter.
Option 033 7%is option provides a 25 kHz adjacent channel filter.
Option 035 This option provides a 30 kHz (Cellular Radio) alternate channel filter.
Option 037 This option provides a carrier noise filter.
Option 050 This option provides increased power measurement accuracy.
Options 907-909 These options are described in Mechanical Equipment Available.
Option 910 This option provides an extra copy of the Operation and Calibration
Manual, and the Quick Reference Guide.
Manual, the Service
Accessories Supplied
The Accessories Supplied are pieces of equipment which
Measuring Receiver. are shipped automatically with every
Line Power Cable on the destination of the original shipment. Refer
Information manual.
The line power cable may be supplied in several plug configurations, depending to Power Cables in Section 2 of this Operating
Fuses Fuses with a 2.5A rating for are supplied. One
115 Vac (HP 2110-0083) (HP
2110-0043) of original destination. Refer to Line Voltage and h e Selection in Section 2 of this Operating
Information manual. a 1.5A rating for 230 Vac fuse is factory installed according to the voltage available in the country
Electrical Equipment Available
This equipment is available to be ordered for the Measuring Receiver after the time of sale.
HP-IB Controller The Measuring Receiver has an compatible computing controller
HP-IB HP-IB
1-4 reu.01 MAR88
Model 8902A General Information
Sensor Module The HP 11722A and 11792A Sensor Modules enable you to characterize a signal using a single input connector. Switching back and forth between the Measuring Receiver’s SENSOR input and RF INPUT switch). The H P 11722A covers the frequency range 100 range 50 MHz is intended for use with the HP 11793A is taken with each sensor module selected RF to connectors happens automatically with these modules (which contain an internal
26.5 GHz and to minimize input SWR and resulting errors. A low input cable further improve SWR and insertion loss.
2.6 GHz; the
Down
HP 11792A covers the
SWR isolates the power sensor from the source-under-test, reducing mismatch. Microwave hardware and a
Down Converter The
HP
11793A Down Converter, when used with a suitable local oscillator, extends the useful range of the Measuring Receiver into the microwave region. Provisions have been made in the Measuring Receiver to account for the frequency of the local oscillator and provide direct display of the frequency of the microwave input signal.
Test Source The HP 11715A AM/FM Test Source produces extremely linear AM and FM at high rates as well adjusting the Measuring Receiver; however, it is an excellent stand-alone instrument for generating very low-distortion as a low-noise
FM
CW signal. This source is required for performance testing and in the broadcast band.
10 dB
Kit A Verification Kit (HP 11812A) is available (which contains a pads, and cable) for verifying the performance of the HP 8902A Option function to reduced specifications. step attenuator,
050 Tuned RF two
Level
Service Accessory Kit A Service Accessory Kit (HP 08901-60287) is available which contains accessories (such as extender boards and cables) useful in servicing the Measuring Receiver.
Front-to-Rear-Panel Connectors Retrofit Kit (Option 001) components and
full
Order HP part number 08902-60026.
This kit contains instructions for converting front-panel connections to all the necessary rear-panel connections.
Rear-to-hont-Panel Connectors Retrofit ponents and
full
Kit (Standard) instructions for converting Option
This kit contains all the necessary com-
001 instruments with rear-panel connections instruments with front-panel connections. Order HP part number 08902-60027. to
High-Stability, Internal-Reference Retrofit Kit (Option 002) This kit contains all the necessary components and full instructions for installation of the high-stability, internal-reference oscillator.
Order HP part number 08902-60281.
Rear-Panel
Local
components and instruments.)
Oscillator Connections Retrofit Kit (Option full instructions for installation of
003) This kit contains
HP part number 08901-60280. (These connections are already included in all the necessary rear-panel local oscillator connections. Order all Option 030 Series
Conversion to
However, operation at line frequencies greater than 66 Hz or equal to
400 Hz
126.5 Vac.
Line Operation
To installation, performance will
Measuring Receivers not equipped frequencies greater than 66 Hz may be converted convert to 400 Hz to will
8902A be restricted
Option 004. to operate operate at line frequencies from at
48 line power to 440 to line voltages less than operation, order HP part number 08902-60029. After rev.24A UG8 7 1-5
General Information Model 8902A
Mechanical Equipment Available
The following kits might have been ordered and received with the Measuring Receiver as options. If they were not ordered with the original shipment and are now desired, they can be ordered from the nearest Hewlett-Packard office using the appropriate part number.
Front-Handle Kit (Option 907) Ease of handling is increased with the front-panel handles. Order HP part number 5061-9690 for the basic kit and 2190-0048 for lockwashers (8 required).
Rack-Flange Kit (Option 908) The Measuring Receiver can be solidly mounted rack using the flange kit. Order HP part number 5061-9678. to the instrument
Rack-Flange and Front-Handle Combination Kit (Option 909) This is not a front-handle kit and a rack-flange kit packaged together; it is composed of a unique part which combines both functions.
Order HP part number 5061-9684 for the basic kit and 2190-9609 for lockwashers (8 required).
Chassis Slide-Mount Kit This kit is extremely useful when the Measuring Receiver is rack mounted.
Access to internal circuits and components or the rear panel is possible without removing the instrument from the rack. Order H P part number 1494-0017 for 432 mm (17 in.) fixed slides. (To order adapters for non-HP rack enclosures, use HP part number 1494-0023.)
Chassis-Tilt, Slide-Mount Kit This kit is the same as the Chassis Slide Mount Kit above except it also allows the tilting of the instrument up or down 90". Order HP part number 1494-0025 for 432 mm
(17 in.) tilting slides. To order adapters for non-HP rack enclosures, use HP part number 1494-0023.
1-9. DESCRIPTION
OF
THE MEASURING RECEIVER
The HP Model 8902A Measuring Receiver is a complete measurement system for accurately characterizing signals in the 150 kHz to 1300 MHz frequency range. separate instruments in its ability and the characteristics of the demodulated audio signal (as well as those of external audio signals).
This flexibility allows you a signal. to to
It combines the capabilities of four measure RF power, tuned RF level, carrier frequency, modulation make those measurements most commonly needed to totally characterize
The Measuring Receiver can measure an RF signal's frequency, frequency tuned, and off-channel), amplitude modulation (AM), frequency modulation (FM), phase modulation
(QM), and AM and FM noise components. signal's frequency and distortion.
It
drift,
recovers the modulating signal and can measure the audio
The Measuring Receiver is fully automatic and all major measurements can be made by pushing a single key. The Measuring Receiver's large digital display shows measurement results with excellent resolution and is easy to read. All Measuring Receiver operations can be controlled and all measurement results can be transferred via the Hewlett-Packard Interface Bus (HP-IB). (HP-IB is Hewlett-Packard's implementation of IEEE Standard 488 and ANSI Standard MC1.l.)
Power Measurements
RF Power
The Measuring Receiver delivers the accuracy and resolution of a high-performance power meter. The
HP 8902A, with the HP 11722A Sensor Module, measures power from +30 dBm to -20 dBm at
frequencies from 100 kHz to 2.6 GHz. (Refer to Table 1-1,
Specifications, for specified frequencies limits using other power sensors. The HP 8902A also accepts all HP 8480 series power sensors for extended measurement capability.)
1-6 rev.24A UG87
Model 8902A General Information input Power Protection damage from the accidental application equipment used to
The Measuring Receiver is equipped with input power protection of excessive power. (This is a common cause of to prevent damage in measure transmitters.) The Measuring Receiver is tested for inputs up to 2W.
Protection is provided by limiting diodes and an RF relay. When excessive power is applied, the relay opens and protects sensitive components, and the Measuring Receiver displays an error message. The circuit automatically resets whenever a key is depressed.
RF Power Calibration RF Power Calibration is accomplished with the 50 MHz, available in every instrument. Also, the front-panel ZERO function enables you to
1 mW standard zero the sensor module without removing it from the source-under-test. After the ZERO key is pressed, the new zero offsets are stored automatically.
RF Power Calibration Factors RF Power Calibration Factors can be entered from the power sensor into the Measuring Receiver’s non-volatile memory. The instrument automatically compensates for the power sensor’s efficiency and mismatch loss at each frequency.
Tuned RF Level The Measuring Receiver has a minimum sensitivity of -127 dF3m with exceptional accuracy. Relative-level measurements with accuracy expected only from a transfer standard can be made.
High Selectivity Measurements Options 030-037 add selective power measurement capability
HP 8902A Measuring Receiver. Used with a low-noise external accurate single-sideband (SSB) to to the
LO, the HP 8902A performs fast,
1.4 GHz.
RF Frequency Measurements
In automatic operation, the Measuring Receiver has the performance of a high-quality, 150 kHz
MHz frequency counter. The frequency counter automatically adjusts itself
There is no need to manually set or adjust the input attenuator. Because the Measuring Receiver usually used to measure modulated signals, significant levels of AM. as to 1300 the input level changes. is its frequency counter also accurately measures signals with
Modulation Measurements
The Measuring Receiver has extremely low internal noise. Incidental AM, FM, and cPM can be measured on a wide range of simple and complex modulated signals. To complement its modulation measurement capability, the HP 8902A characterizes audio signal level, frequency, and distortion. (These features are also available for external audio signals.)
Filters, De-emphasis Networks and Modulation Calibrators
Post-Detection Audio Filters The Measuring Receiver has two high-pass and three low-pass post- detection audio filters for filtering the recovered modulation. These filters can be selected individually or in combination. Their cutoff frequencies have been chosen to match those needed for applications such as transmitter or signal generator testing. The $0 kHz filter is a Bessel filter. It minimizes overshoot for square-wave modulation so that this type of modulating waveform can also be accurately measured.
De-Emphasis Networks The Measuring Receiver contains four de-emphasis networks that can be used in addition to the audio filters. These are the ones commonly used in FM communications-25,
50, 75, and 750 ps. When selected, the de-emphasis networks always affect the demodulated output.
You can select whether the de-emphasis network affects the deviation measured. The ability to select either the actual or “de-emphasized deviation“ increases the usefulness of the Measuring Receiver in many applications. reu.24A
UG87
1-7
General Information Model 8902A
Modulation Calibrators measurements of AM depth or FM deviation is generating calibration standard. In all instruments, a precise AM and a precisely modulated signal
FM modulation standard is to use included. as a
When the output of the calibrator is connected of modulation is measured to to the Measuring Receiver’s input, the amount create a calibration factor. The calibration factor can be used
9%. to automatically compensate all subsequent measurements. The calibration factor is the ratio of the measured modulation to the internally-computed modulation of the calibrator, expressed in
Additional Features
Tuning Features signal
In automatic operation, the Measuring Receiver automatically tunes and measures it. to the input
In manual operation, you can determine the frequency the approximate frequency on the keyboard causes all but very close interfering signals
This allows the Measuring Receiver to to which the Measuring Receiver tunes. Entering to be eliminated. selectively measure signals other than the largest.
A track mode feature enables you to track a signal, as it changes frequency, from either automatic or manual tune operation.
Store and Recall functions These functions enable you to store eight complete instrument settings in non-volatile memory and recall them as needed.
Display Flexibility The Measuring Receiver offers numerous data-display formats. For example, RF power and tuned RF level can be displayed in
RATIO and LOG/LJN keys to watts, display results in dBm, dB or 9%
V, dBV, mV, dBmV, pV, and dBpV. relative to either a measured value or
Use the a value entered from the keyboard. These features eliminate the need for recalculating measurement results.
Special Functions
The Measuring Receiver can do more than is apparent from the front panel. Many functions are accessed using the numeric keys and a Special Function key. The Special Functions provide access to other measurements and functions, manual control of instrument functions, instrument operation verification, and service aids.
All instrument functions not set using these Special h c t i o n s remain in the automatic mode. This allows you to select any combination of manual or automatic operations. By depressing the special key alone, the display shows ten digits that indicate which functions are in automatic and the those manually set. state of
There are also numerous Special Functions that can be and repairing the Measuring Receiver faster and easier. used in verifying that the instrument and its various sections are operating properly. These, along with service special functions, make diagnosing
Those Special Functions that are most commonly used in operating the Measuring Receiver are described on the Special finction Information pull-out card under the front panel.
Extending Measurement Range
Operation to the external
42
GHz
is accomplished when an external LO and mixer are included in the measurement path. This system then functions as a single instrument making microwave modulation, frequency, power, and level measurements. You control operation from the Measuring Receiver’s front panel. When
LO frequency must be changed, the Measuring Receiver requests an external controller to make the change. A separate, non-volatile calibration factor table is available in Frequency Offset mode for your microwave power sensor.
1-8 reu.24A UG87
Model 8902A General Information
Programmability
IB). This, coupled with the diversity of measurements the Measuring Receiver can make, the speed with which these measurements can be made, and the flexibility of the Special h c t i o n s , make the instrument ideal for systems applications. In many instances it can reduce the number of instruments in a system, speed measurements, reduce complexity and improve accuracy.
When the Measuring Receiver is in remote, the front-panel annunicators make it very easy the state the instrument is in, whether it is in the
talk,
or service request state. to determine
1-10.
PRINCIPLES
OF
OPERATION
USING A
SIMPLIFIED BLOCK DIAGRAM
The Measuring Receiver is a calibrated, superheterodyne receiver, which converts the incoming signal to a fixed, intermediate frequency
(QM)),
(IF), which is then demodulated. As
Receiver contains an RF amplifier, a local oscillator (LO), a mixer, an in a radio receiver, the Measuring
IF amplifier and bandpass filter, a demodulator (detector or discriminator), and audio filters (tone controls). The Measuring Receiver, however, contains additional features which make it much more versatile:
0 automatic tuning,
0 selectable measurement mode: signal frequency, power level, or modulation (AM, FM, or Phase
Modulation
0
0
0
0
0
0
0
RF power level measurements on tuned signals to -127 dBm (0.1 pV), relative RF level measurements on out-of-channel signals selectable audio detector (peak, average, audio counter, audio distortion analyzer, measurement calibrators (AM,
HP-IB programmability.
FM, or
rms
responding), or power level), and to -129 dBc (Option Series 030),
The entire operation of the instrument is governed by a microprocessor-based Controller. The Controller sets up the instrument at turnon, interprets keyboard entries, executes changes in internal hardware, and displays measurement results and error messages. The computing capability of the Controller is also used to simplify circuit operation. For example, a). it forms the last stage of the Counter, calculates the AM or FM generated by the AM and FM Calibrators, and converts measurement results into ratios
(in % or The Controller also contains routines useful for servicing the instrument.
RF
Circuitry
The RF input signal normally enters an external Sensor Module such as an HP 11722A. (See Figure
1-2.) For all measurements except RF Power, the Sensor Module routes the signal conector of the Measuring Receiver. For the into the Power Sensor, which converts the RF the RF input
Power measurement, the input signal passes directly power absorbed by the frequency, chopped, ac voltage whose amplitude is proportional
Meter amplifies the chopped signal and converts it to to
RF Power Sensor into a low- the average RF power. The Power a dc voltage which is then measured by the
Module to the CALIBRATION RF POWER OUTPUT connector on the front panel. (The 50 MHz
Power Reference Oscillator is an accurate 1 mW reference.) to voltmeter. (The voltmeter includes the Audio Peak Detector, Audio Average Detector, Voltage-to-Time
Converter, and Counter.) The calibration of the Power Meter can be verified by connecting the Sensor re v.24AUG8 7 1-9
General Information Model 8902A
1-10
CAUTION
The Power Sensor is irnproftwed against and is easily damagcd by sudden, large overloads. Refer to Table I- I under RF Power, Sirpplemcntal Charac- teristics, RF Power Ranges
of
HP 8902A Measuring Receiver with HP
Sensor Moditkc, for injormation on maximirm operating levels.
I1
The broadband, low-noise RF Amplifier improves the sensitivity of the Tuned RF Level measure- ment. The amplifier is normally bypassed in the other measurement modes.
CAUTION
A n RI: defecfor in the RF AmpliJim
AmpliJier to damaged by be relatively long switching timc (approximately 30 mJ), the
a
bypassed when large an
(nof shown in Figirrc overload. Refir to Tabk
Level, .for injormafion on
1-1, itndcr RF Inpiit, Optrating maximitm opcraf ing Icvcl.~.
I-2) caiws thc RF overload occirrs. However, becairse of the
When the RF Peak Detector senses that the input signal level exceeds 1 W, it opens the Overpower
Relay. This is done without intervention of the Controller. The output from the R F Peak Detector, read by the voltmeter, is used to set the Input Attenuator to optimize the level applied to the Input
Mixer.
The Input Mixer converts the input signal to the intermediate frequency (IF). For frequencies greater than 10 MHz, the IF is 1.5 MHz with the Local Oscillator (LO) tuned 1.5 MHz above the input frequency; an IF of 455 kHz can be manually selected for this frequency range. The 455 kHz IF is selected automatically for input signals between 2.5 MHz and 10 MHz and for the Tuned RF Level measurement at all frequencies. Below 2.5 MHz, the input passes directly through the Input Mixer without down-conversion. (The Tuned RF Level measurement is invalid below 2.5 MHz.)
NOTE
For fhc inpitf signal the LO mirst sfill of' 101.5 MHz is arbitrarily iiscd. Thus jrqrrencies of' I00
2.5 MHz. to hc or pass fhroirgh thc Input Mixer withoitt down-conversion, prtwnt
103 to fitrn thc mixcr diodes
MHz
as
well fhc insfrirmenf will rcspond fo inpitt
as
jrqiicncics
on.
A n het ween
LO j-cqiicncy
150 kHz and
The instrument can be manually tuned to a desired signal even in the presence of larger signals, although filtering may be necessary since low-frequency signals pass directly into the IF. The RF
High-Pass Filter can be inserted (via a Special Function) in the R F path for this purpose.
To measure the input frequency, the Counter measures the frequency of the LO and the frequency of the IF from the output of the IF Amplifier and Filter. The Controller computes and displays the difference between the two frequencies. For input frequencies below 2.5 MHz, only the IF is counted, which equals the input frequency.
LO Circuitry
The LO drives the high-level port of the Input Mixer and is one of several inputs to the Counter.
The LO has four main modes of operation:
0
0 tuning to the frequency required to down-convert a signal whose frequency is entered from the keyboard (manual tune mode), automatically searching for an input signal, then tuning the LO to the frequency required to down-convert the signal (automatic tune mode),
Model 8902A General Information
0
0 automatically searching for an input signal, then configuring the LO in a feedback loop that automatically tracks the signal (automatic tune track mode), and tuning to the frequency required to down-convert a signal whose frequency is entered from the keyboard, then configuring the signal (manual tune track mode).
LO in a feedback loop that automatically tracks the input
The manual tune track mode is useful when it is desired to follow an unstable signal in the presence of other signals. The non-track modes are used when the LO noise (residual FM) must be minimized.
IF
Circuitry
The gain of the IF Amplifier is fixed except for the Tuned R F Level measurement mode (described below). The IF Filters determine the frequency response of the IF. The I F Filters can be manually selected with Special Function the IF filter consists of a 150
3 as described in the following table. When the 1.5 kHz to 2.5
MHz IF is selected,
MHz bandpass filter (with a nominal center frequency of
1.5 MHz). When the 455 kHz I F is selected, the I F filter is the Wide 455 kHz Bandpass Filter (with a bandwidth of 200 kHz) except for the Tuned R F Level measurement mode where the Narrow
455 kHz Bandpass (with a bandwidth of following table.)
30 kHz) is also inserted. (Other exceptions are noted in the
I
Frequency Range
10 to
2.5 to
1300
10
150 kHz
MHz
MHz to 2.5 MHz
-
Special Function
Tuned RF Level
3.6
3.5
I
All Others
3.2
3.1
3.2
In the Tuned R F Level measurement mode, the signal (after amplification by IF Amplifier, which is now a precision, variable-gain amplifier) is detected by the I F Synchronous Detector, which phase locks to and tracks the IF signal. The narrow bandwidth of the phase lock loop (150 Hz) makes it possible for the detector to measure the signal level even when the signal is buried in noise.
To enhance the accuracy of this low-level measurement, the operator must first provide a high- level signal at the desired frequency. (The range of acceptable levels depends on the type of Power
Sensor used.) The level is measured by both the Power Meter (which is assumed to be the calibration standard) and the IF Synchronous Detector. From the two power measurements, the Controller computes a calibration factor, which corrects subsequent level measurements made at the same frequency.
Another way of making a tuned R F level measurement is with the IF Average Detector (accessed with
Special Function 4). which is part of the AM Demodulator. (Refer to Tiincd RF Levrl in the DtI/aikd
Opcruting In.ilriit'/ion.s of Section 3 in this Opcruiing Inliwrncrfion manual.) Although somewhat less sensitive than the I F Synchronous Detector, the IF Average Detector has a wider bandwidth, which gives it the ability to make measurements on signals with higher residual FM.
In instruments with Option Series also includes a precision, variable-gain amplifier) and detected by the IF
Filters set the IF
030, the IF signal is further processed by the Channel Filters (which
RMS Detector. The Channel bandwidth and gain for the Adjacent Channel measurement. The measurement is made by entering a series of Special Functions which establish an IF reference in the center of the
Channel Filter, then allow the relative IF level to be displayed as the IF frequency is detuned by a pre-determined offset.
Audio
Circuitry
The modulation on the IF is demodulated by either the AM or the FM Demodulator. Phase mod- ulation is recovered by integrating the demodulated FM in the Audio Filters and Gain Control circuitry.
1-1 1
General Information Model 8902A
The demodulated signal is amplified and filtered in the Audio Filters and Gain Control circuitry. The filters are selected from the front panel, and for processed signal is passed and the voltmeter. to
FM, the filtering may also include de-emphasis. The the front-panel MODULATION OUTPUT/AUDIO INPUT connector
The audio signal from the Audio Filters and Gain Control is converted to a dc voltage by the Audio
Peak Detector, the Audio Average Detector or the Audio RMS detector. The Audio Average and
RMS Detectors are used primarily for measuring noise. The output from the detectors is routed into the Voltage-to-Time Converter.
The Voltage-to-Time Converter within the voltmeter converts the dc input into a time interval.
During the interval, the 10 MHz Time Base Reference is counted by the Counter, and the resultant count represents the dc voltage. Other inputs to the voltmeter, which are not shown, include outputs from an audio level detector and the AM calibrator.
The Distortion Analyzer measures the distortion of either the internal demodulated signal or an audio signal applied externally to the MODULATION OUTPUT/AUDIO INPUT connector. The frequency of the input signal must be either 1 kHz or 400 Hz. The distortion on the signal is deter- mined by measuring the amplitude of the signal before and after a notch filter that is set to 1 kHz or
400 Hz. The two ac signals are converted to dc by a the Audio RMS Detector and then measured by the voltmeter. Distortion is computed as the ratio of the voltage out of the notch filter to the voltage into the filter. (The Audio RMS Detector can also be used to measure the demodulated AM,
FM, or <PM internally or the ac level of an external audio signal applied to the MODULATION
OUTPUT/AUDIO INPUT connector.)
The frequency of the audio signal at the MODULATION OUTPUT/AUDIO INPUT connector, whether internal or external, is measured by a reciprocal-type Audio Counter. In the Audio Counter, the input signal is used to gate the 10 MHz Time Base Reference into the main Counter. (This gating function is also used by the Voltage-to-Time Converter.) The number of time base pulses received during the count is read by the Controller which computes and displays the signal frequency.
The AM and FM Calibrators provide a nominal 10.1 MHz signal with a precisely known amount of AM or FM. When this signal is applied to the instrument’s RF INPUT connector (either directly or via the Sensor Module), the modulation is measured and the calibration factor of the AM or
FM Demodulator is computed and displayed. Related front-panel functions are automatically set for proper demodulation of the calibrator signal.
1-1 1. MODULATION BASICS
The Measuring Receiver can demodillate and memire three types of modulation: amplitude mod- ulation (AM), frequency modulation (FM), and phase modulation (QM). In general, modulation is that characteristic of a signal which conveys the information. A signal without modulation is said to be a continuous-wave (CW) signal. CW signals contain two information-carrying parameters: am- plitude and frequency. These two parameters, however, are static (time invariant). Consequently, the information conveyed by them is scant-you know only that a signal is present at a certain frequency. When one or both of these parameters is altered to be modulated. as a function of time, the signal is said
The RF signal which is modulated is called the carrier. The modulating signal is referred to as the baseband signal and can be of any arbitrary form (for example, voice, tone, noise). Demodulation is the process of recovering the baseband signal from the modulated carrier. The Measuring Receiver can measure the modulation on carriers in the range of 150 kHz to 1300 MHz. Measurement accuracy is specified for modulation rates generally between 20 Hz and 100 kHz. The demodulated signal is present at the MODULATION OUTPUT connector.
Amplitude Modulation
As the name implies, a carrier is amplitude modulated when its amplitude is varied as a function
1-12
POWER
EASURING RECEIVER
I
I m-1
OElECTOR
PEAK
TIME BASE
10 MH2
General Information Model 8902A of time. Figure baseband signal.
1-3
As shows a carrier with amplitude modulation and, for reference, also shows the you can see, the tips of the carrier trace out a waveform that resembles the baseband signal. This trace is called the envelope. The envelope rises to a maximum called the peak and drops to a minimum called the trough.
BASEBAND SIGNAL
1.5
1.0
0.5
0
I
(b) AMPLITUDE MODULATED CARRIER
Figure 1-3. A Baschmd Signal and the Corrcsponding A mplititde Moditlaled Carrier
A quantity which describes the amount of AM or the AM depth is the modulation index. If the peak amplitude is called P and the trough amplitude is called expressed in Yo) is defined as
T,
m (usually
P - T
+ x 100%.
In the example of Figure 1-3,
P
= 1.5 and
T
= 0.5: therefore,
+
0.5 x 100% = 50%.
Figure 1-4 shows AM signals with modulation indexes varying from 0 to 100%.
When the baseband signal is symmetrical, the modulation index can also be expressed in terms of the average carrier level,
= A - r,
A, and the envelope peak, r, relative to the carrier. Then and the expression for modulation index becomes
P = A
+ r, and
A + r - A + r
A + r + A - r x 100% = -
2A
100% = -
A x 100%.
This is the expression which the Measuring Receiver evaluates when making an AM measurement.
Referring back to Figure 1-3, it is aljparent that A = 1 and r = 0.5 so m =
-
1
100% = 50% as before.
1-14
Model 8902A General Information
(a) 0% AM (CW)
(b) 30% AM
(c) 70% AM
(d) 100% AM
The Measuring Receiver makes an A M measurement by forcing the average carrier level, A, to a known, fixed level by means of an automatic level control (ALC) circuit. The signal is then demod- ulated. and the amplitude of the recovered baseband signal is measured with a peak detector. The output of the detector is r, which is (in effect) multiplied by the constant 100/A and displayed as the
Yo AM.
Figure 1-5 illustrates an A M signal with an asymmetrical baseband source. The first definition of modulation index still applies here. For it, m = 46%. The second definition, however, does not apply since P if A - T. The Measuring Receiver detects a different value for r if the positive peak of the recovered signal is detected than if the negative peak is detected. Thus a different modulation index is
- A measured i n PEAK+ than PEAK-.
1-15
General Information
(a) BASEBAND SIGNAL
Model 8902A n
(b) AMPLITUDE MODULATED CARRIER
Figwe 1-5. A M wilh an A symmelrical Basehand Signal
The range of modulation indexes for AM measurements by the Measuring Receiver is essentially
0 to 100"/0. of moddation that produce modulation indexes greater than
AM. The Measuring Receiver is not intended for measuring such signals. Nevertheless, there are cases, when the Measuring Receiver will display a modulation index that exceeds 100Yo. This can occur, for example, o n an asymmetrical waveform where a narrow peak is greater than the average carrier level. This is illustrated in Figure 1-6.
I
1-16
Exponential Modulation
Exponential (or angular) modulation is the generic name given to modulation in which the frequency or phase of the carrier is varied. Frequency and phase modulation are very closely related. In fact, it is impossible to tell whether the signal was produced by a frequency modulator or phase modulator by analyzing the received signal iinless specific information about the baseband signal is given.
It is certainly true to say that a signal is frequency modulated when the modulation is generated by frequency niodulator. A varactor- diode across the tank circuit of an when the varactor bias is varied. It is also true that a signal is
LC a oscillator will produce FM phase modulated when the modulation is generated by a phase modulator. A varactor diode across an RF filter will produce QM when the varactor bias is varied. (It is assumed that the carrier- is on the slope ofthe filter and that the filter is
Model 8902A General Information driven from a well-buffered carrier source. This modulator simultaneously produces AM.)
The signal from both modulators will show readings on the Measuring Receiver when in both the
FM and QM measurement modes. When in FM, the quantity being measured is the peak frequency deviation, which is the maximum frequency excursion from the average carrier frequency. When measuring QM, the peak phase deviation is measured, which is the maximiim phase excursion from the average carrier phase. Phase and frequency have the relationship that phase is the integral of the frequency or frequency is the derivative of the phase. In fact, the Measuring Receiver demodulates i9M by integrating the demodulated FM.
This relationship is most easily visualized by some examples. Look at Figure 1-7. The first baseband signal shown is a square wave. The three waveforms under it are the result of applying this signal to a n
FM, @M, and AM modulator respectively. (The AM waveform is included only for reference.) It is assumed that the phase modulator doesn't produce AM-only i9M. The FM waveform is as expected.
The frequency goes up on the positive peak of the baseband signal and down on the negative peak.
The phase modulated signal, however, is peculiar. The frequency is generally constant throughout except for a discontinuity where the baseband signal switches amplitude. The waveform of the figure was contrived so that a 180" phase shift occurred exactly at a zero crossing of the carrier. In general, a discontinuity will occur when the baseband signal switches amplitude, but the phase shift is not necessarily 180" and does not need to occur at a zero crossing of the carrier. Mathematically, the derivative of a square wave is the constant zero except for a positive spike (impulse) where the baseband signal switches positive and a negative spike where the square wave switches negative.
Now look at the triangle wave. The frequency modulator produces a continually increasing fre- quency as the baseband signal slopes upward and a continually decreasing frequency as the signal slopes downward. The phase modulator produces quency modulator for a signal that resembles the signal from the fre- the square wave baseband signal. This is because the derivative of a constant slope is a constant. When the slope is positive, the phase shift is continually increasing, thus pro- ducing a uniform frequency shift upward. When the slope is negative, the phase shift is continually decreasing and produces a downward frequency shift. For the triangle wave baseband signal, the shift in frequency when the slope changes is proportional to the change in slope.
Now note the sine wave of Figure I-~(c). The signals from the frequency and phase modulators look the same except for the frequency is
90" highest when the baseband signal is most positive and lowest when most negative. is phase shift between the two. For the frequency modulated signal, the most negative.
For the phase modulated signal, the frequency is highest when the slope of the baseband signal is steepest in a positive direction. This occurs at the positive-going zero crossing. Similarly, the frequency is lowest when the slope
If in the last example, the rate, but not the amplitude, of the baseband signal is increased, the highest and lowest frequencies of the signal from the frequency modulator stay the same-they just occur more often. However, for the signal from the phase modulator, not only d o the frequency peaks occur more often, but the excursions are large because the slopes of the baseband signal are steeper at the zero crossings. See Figure 1-7(d).
The maximum frequency deviation which can be measured is 400 kHz. The maximum phase devi- ation is 400 rad or 400 kHz divided by the modulation rate, whichever is smaller. As with AM, an asymmetrical baseband waveform will result in different readings in PEAK+ than PEAK-.
Other Considerations
In practice, it is difficult to produce an FA4 or QM not also have a small amount of
AM-called incidental AM or AM-on-FM. Likewise, an AM signal usually contains a small amount of incidental FM and +M. In order to accurately measure this incidental modulation, the Measuring
Receiver itself must not contribute to it. This contribution is specified rejection. as AM rejection and FM
A typical CW signal also contains a sniall amount of residual AM, FM, and +M. The residual
1-17
General Information Model
I
BASEBAND SIGNAL
SIGNAL FROM FREQUENCY MODU LATD R
SIGNAL FROM PHASE MODULATOR
BASEBAND SIGNAL
SIGNAL FROM FREQUENCY MODULATOR
SIGNAL FROM PHASE MODULATOR
8902A
1-18
SIGNAL FROM AMPLITUDE MODULATOR
(a) SQUARE WAVE BASEBAND SIGNAL
SIGNAL FROM AMPLITUOE MODULATOR
(b) TRIANGLE WAVE BASEBAND SIGNAL modulation is generated by siich things as line hum, noise, and microphonics. The residual AM and
FM specifications quantify the residual modulation internal t o the Measuring Receiver.
Residual modulation affects the modulation readings in used, the natiire of the residuals, and the signal-to-noise ratio. If the residual is predominately noise, when the peak detector is used, the residuals add in a way that is statistically related to the signal- to-noise ratio. This is disciissed under
Section 3. When the average detector
Re,idiiul Noiw I$]>C[S in the Dc>(uilcd is a manner which depends o n the detector
Opcwlrng /n$(riic(iwi) used, the residuals add approximately in an rms manner, that is, the square root of the sum ofthe squares ofthe noise and the signal. The effect of this noise becomes insignificant, however, when the signal-to-noise ratio rises above a few dB. Noise can be further reduced by filtering the demodulated signal.
In p s
FM signal broadcasting and communications, the signal-to-noise ratio is improved by giving the baseband a high-frequency boost before applying it to the modulator. This boost is a simple 6 dB per octave with the
(which corresponds to a demodulated display.
3
3 dB corner of 2.12 is called pre-emphasis. The dB corner specified by a time constant: for example, kHz)
75
FM. If desired, the
FM can be de-emphasized to equalize the signal at the modulation outpiit and at the
Model 8902A
General Information
BASEBAND SIGNAL
SIGNAL FROM FREQUENCY MODULATOR
SIGNAL FROM PHASE MODULATOR
BASEBAND SIGNAL
SIGNAL FROM FREQUENCY MODULATOR
SIGNAL FROM PHASE MODULATOR
SIGNAL FROM AMPLITUDE MODULATOR
(c) SINE WAVE BASEBAND SIGNAL
~~
A mplirilde Modda(ors jor Varioi(s Uascbartd Signals
SIGNAL FROM AMPLITUDE MODULATOR
(d) SINE WAVE BASEBAND SIGNAL: 3/2THE RATE OF (c)
1-19
General Information Model 8902A
Table 1-1. SpcciJicalions
(I
of 7)
SPECIFICATIONS describe the instrument's warranted performance.
SUPPLEMENTAL CHARACTERISTICS (shown in italics) are intended to provide information useful in applying the instrument by giving typical, but non-warranted performance parameters.
Frequency Modulation
RATES?
20
20
Hz to 10 kHz, 150 kHz I f c
Hz to 200 kHz,
DEVIATIONS@:
<lo
MHz.
1 1 3 0 0 MHz.
40
400 kHzpeak maximum, 150 kHz I f c - 3 0 MHz. maximum, 10 MHz Sfc 11300 MHz.
ACCURACY's2@:
10 MHz I f c
FM Accuracy
22% of tl reading digit
2
1 % of
+1 reading digit
Frequency Range
250 kHZ-10 MHz 20 Hz-10 kHZ 540 kHZpeak
10 MHZ-1300 MHZ
Rates Deviations
50 HZ-100 kHZ 5400 kHZpeak
25% of
21 reading diait
10 MHz-1300 MHZ 20 Hz-200 kHZ 5400 kHZpeak
For rms detector add e3Y0 of reading.
DEMODULATED OUTPUT DISTORTION6*':
I
THD
<0.1%
I
FrequencyRange
400kHz-lOMHz
I
I
Rates
20Hz-lOkHz
I
Deviations
<lokHz
I
<0.1%
I
10MHz-1300MHz
I
20Hz-100 kHz
I
4 0 0
1
I
I
I
AM REJECTION (50 Hz to 3 kHz BW)?
AM Rejection
HZ peak
I I
Frequency Range
150 kHz-1300 MHz
I
I
400
~
Rates
Hz or 1 kHz
1
I
AMDepths
550%
RESIDUAL FM (50 Hz to 3 kHz BW): <8 Hzrms at
1300
<1
MHz, decreasing linearly with frequency to
Hzrms 100 MHz and below.
I
Supplemental Characteristics:
MAXIMUM FM DEVIATION, RESOLUTION, AND
MAXIMUM DEMODULATED OUTPUT SENSITIVITY
ACROSS AN OPEN CIRCUIT (600Q output impedanceI5:
Maximum
Resolution
Maximum
Demodulated Output
Sensitivity
Deviations [A F)
0.7 mV/Hz
1
4.0 kHz 5
A Fneak <40 kHz
I
I
Resolution is increased one digit with 750 gs de-emphasis and pre-display on.
The demodulated output signal present at the
Modulation Out/Audio In connector is increased in amplitude by a factor of 10 with 750
/IS de-emphasis.
1
I
DEMODULATED OUTPUT DISTORTION7:
THD
<0.3%
Frequency Range
750 kHz-400 kHz
Rates
20 HZ-70 kHZ
Deviations
<70 kHz
Amplitude Modulation
RATES:
20
20
Hz to 10 kHz, 150 kHz I f c <10 MHz.
Hz t o 100 kHz, 10
DEPTH: to 99%.
MHz 5 f c 51300 MHz.
I
I
I
ACCURACY'V~.~:
AM Accuracy
22%
~~ of reading
2 1 digit
+3% of
+1 reading diOit
2
1 % of
21 reading diait
"'70
Of
21 reading digit
I
I
I
Frequency Range
150kHz-lOMHz
I
I
Rates
50Hz-10 kHz
I
I
Depths
5%-99%
150 kHz-10 MHz
1
20 Hz-10 kHz
1 to 99%
I
10MHz-1300MHz
1
50Hz-50 kHz
I
5%-99%
10 MHz-1300 MHz 20 Hz-100 kHz to 99%
For rms detector add 2 3 % of reading.
I
FLATNESS4+
Flatness
20.3% of reading2 1 digit
I
I
Frequency Range
10MHz-1300MHz
I
I
Rates
90Hz-lOkHz
DEMODULATED OUTPUT DISTORTION:
<0.3%
<0.6% THD
550%
195% depth. depth.
FM REJECTION (50 Hz to 3 kHz BW)?
1
I
Depths
20%-80%
FM Rejection
<0.2% AM
<0.2% AM
Frequency Range Rates FM Deviations
250 kHz-10 MHz 400 Hz or 1 kHz <5 kHZpeak
10 MHz-1300 MHz 400 Hz or 1 kHz <50 kHZneak
~
RESIDUAL AM (50 Hz to 3 kHz BW): <0.01%,,,.
~
'Not to exceed for stated accuracy: 50 Hz to 40 kHz rates with rms detector.
Peak residuals must be accounted for in peak readings.
For peak measurements only: AM accuracy may be affected by distor- tion generated by the measuring receiver. In the worst case this distortion can decrease accuracy by 0.1% of reading for each 0.1% of distortion.
Flatness is the variation in indicated AM depth for constant depth on input signal.
For optimum flatness, cables should be terminated with their character- istic impedance.
'But not to exceed: 20 kHz rates and 40 kHz peak deviations with 750 FS
'
750
LIS de-emphasis and pre-display "off," distortion is not speci- fied for modulation outputs >4V peak. This condition can occur near maximum deviation for a measurement range, at rates C2 kHz.
I
I
1
1-20
Model 8902A
1-1. Specificafions
Amplitude Modulation, continued
Supplemental Characteristics:
DETECTORS: +peak, -peak, +peak/2, peak hold, average [rms sinewave calibrated), rms.
MAXIMUM DEPTH, RESOLUTION, AND MAXIMUM
DEMODULATED OUTPUT SENSITIVITY ACROSS A N
OPEN CIRCUIT (6000 output impedan~e)~: of 7)
Modulation Reference
AM CALIBRATOR DEPTH AND ACCURACY: 33.33% depth nominal, internally calibrated to an accuracy of
20.1%.
FM CALIBRATOR DEVIATION AND ACCURACY:
34 kHzpeak deviation nominal, internally calibrated to an accuracy of 20.1%.
Maximum
Resolution
0.1 %
0.01%
Maximum
Demodulated Output
Sensitivity
0.01 V/percent
0.1 V/percent
AMpeak?40.0%
AMpeak<40.Ooh
Supplemental Characteristics:
CARRIER FREQUENCY: 10.1 MHz.
MODULATION RATE: 10 kHz.
OUTPUT LEVEL: -25 dBm.
0.007%
(rms detector only)
0.1 V/percent
Phase Modulation
AMrm,<3.0%
RATES:
200
200
Hz to 10
ACCURACYz: kHz, 150 kHz Sfc <10 MHz.
Hz to 20 kHz, 10 MHz 1 f c 11300 MHz.
=4% of reading e1 digit, 150 kHz I f c < I O MHz.
23% of reading 21 digit, 10 MHz I f c 11300 MHz.
For rms detector add 23% of reading.
DEMODULATED OUTPUT DISTORTION: <O.l% THD.
AM REJECTION (for 50% AM at 1 kHz rate)':
<0.03 radians peak (50 Hz to 3 kHz BW).
~
.
MAXIMUM DEVIATION, RESOLUTION, AND
MAXIMUM DEMODULATED OUTPUT SENSITIVITY
I
ACROSS AN OPEN CIRCUIT (600Q output impedan~e)~:
1
Frequency Counter
RANGE: 150 kHz to 1300 MHz.
SENSITIVITY:
1 2
22 mVrms mVrms
(-25
(-20 dBm), 150 kHz I f c 1650 MHz. dBm), 650 MHz <fc 11300 MHz.
MAXIMUM RESOLUTION: 1 Hz.
ACCURACY
+reference accuracy digit, fc<lOO MHz.
=reference accuracy
=
=
3 counts of least-significant
3 counts of least-significant digit or 30 Hz , whichever is larger, f$lOO MHz.
Supplemental Characteristics:
MODES: Frequency and Frequency Error [displays the difference between the frequency entered via the keyboard and the actual RF input frequency).
SENSITIVITY IN MANUAL TUNING MODE:
Approximate frequency must be entered from keyboard. 0.22 mVrms dBm).
Using the RF amplifier and the IF amplifiers, sensitiv- ity can be increased to approximately -100 dBm.
I
40 s n
5
$
20
10
4.0
20
2
10
2
4
1
100 200 T400 rms 6atec1of
O.OW1 only
Raaian ResoIutlon
_ ~ ~ l k 2k 4k
Modulation Rate (Hz)
10k 20k
_
Supplemental Characteristics:
MODULATION RATES: usable from 20 Hz to 100 kHz with degraded performance.
DETECTORS: +peak, -peak, +peak/2, peak hold, average [rms sinewave calibrated), rms.
I
'Peak residuals must be accounted for in peak readings.
For optimum flatness, cables should be terminated with their character- istic impedance.
After 30-day warm-up.
Short-Term Stability
General Information
Internal Time Base Reference
FREQUENCY: 10 MHz.
AGING RATE: <1 x 10-6/month.
<I x 10-~/day (Option 002)8.
Supplemental Characteristics:
INTERNAL REFERENCE ACCURACY: Overall accuracy is a function of time base calibration, aging rate, temperature effects, line voltage effects and short-term stability.
~~ ~~
Standard Option 002
Aging Rate
Temperature Effects
~
Line Voltage Effects
(+5%, -
10% Line Voltage
Change)
<1 x 10-6/mo.
<2 x 10-7/Oc
<1 x 10-6
<1 X 10-g/day
<2 x lO-'O/OC
<6 x
I - I
1 sec. average
I
1-21
General Information Model 8902A
1-1. Specifications (3
of
7)
RF Power
The HP 8902A Measuring Receiver, with HP 11722A Sen- sor Module, performs RF power measurements from -20 dBm (10 PW) to +30 dBm (1W) at frequencies from 100 kHz to 2.6 GHz. The HP 8902A can be used with the HP 11792A
Sensor Module and any of the HP8480 series Power
Sensors (HP 8481A/lB/lH/2A/ZB/2H/3A/4A/5A/6A) to make power measurements from -70 dBm (10 pW) to
+44 dBm (25W) at frequencies from 100 kHz to 50 GHz.
The HP 8480 Series Sensors also work with the HP 435A,
HP 436A and HP 438A Power Meters. Unless otherwise specified, the specifications shown below refer to the
HP 8902A only. A detailed explanation of how the uncer- tainty specifications provided below affect the absolute power measurement accuracy of the HP8902A is pro- vided in Application Note 64-1.
RF POWER RANGES OF HP 8902A MEASURING
RECEIVER WITH HP 11722A SENSOR MODULE:
-20
-10
0
+10
+20 dBm to -10 dBm (10 pW to 100 pW), range 1. dBm to 0 (100 pW to 1 mW), range 2. dBm to +10 dBm (1 mW to 10 mW), range 3.
< I O
<I
<ZOO dBm to $20 dBm (10 mW to 100 mW), range 4. dBm to +30 dBm (200 mW to 1 W), range 5.
RESPONSE TIME (0 to 99% of reading): seconds, range second, range 2.
1. milliseconds, ranges 3 through 5.
DISPLAYED UNITS: Watts, dBm, dBrelative, mV, pV, dB V, dB mV, dB pV.
%re,,,tive, volts,
INTERNAL NON-VOLATILE CAL FACTOR TABLES
(user modifiable using special functions):
RF POWER RESOLUTION9:
0.01%
0.01 of full scale in watts or volts mode. dB in dBm
LINEARITY or dBrelativr
(includes sensor RF linearity 2RF range-to-range change error. range
Maximum Number of Cal Factor/Frequency Entries:
Table #1 (primary): 16 pairs plus Reference Cal
Factor.
Table #2 (frequency offset): 22 pairs plus
Maximum Allowed Frequency Entry: 200 GHz.
Frequency Entry Resolution: 50
Cal Factor Range: 40 to 120%.
Cal Factor Resolution: 0.1 %
.
Reference Cal Factor. kHz. RF RANGE LINEARITY
20.02 dB, 2
20.03 dB, RF range 1.
(using through least-significant digit.
Recorder OutputYO:
5.
Using front-panel display add
2 1 count of
RF RANGE-TO-RANGE CHANGE ERROR (using
Recorder Output):
2 0.02 dB/RF range change from reference range. Using front-panel display add 21 count of least-significant digit.
INPUT SWR: using HP 11722A Sensor Module.
ZERO SET (digital settability of zero): +0.5%=1 count of
10 full scale on lowest range. Decrease by a factor of for each higher range.
Supplemental Characteristics:
Power Reference
POWER OUTPUT: traceable to the
1.00
U.S.
+0.7%,
ACCURACY: 21.2% worst case (20.9% rss)
(0% to 55%). for one year
Supplemental Characteristics:
FREQUENCY: 50 MHz nominal.
SWR: nominal.
FRONT PANEL CONNECTOR: Type4 female.
ZERO DRIFT OF METER: 20.03% range. offill scale/"(= on lowest range. Decrease by a factor of 10 for each higher
NOISE (at constant temperature, peak change over any
1-minute interval for the HP 11 722A Sensor Module and HP 8481A/lB/1 H/ZA/ZB/ZH/3A/5A/6A Sensors):
0.4% offull
0.13% offull scale on range
0.013% of
0.0013%
0.00013% scale on range full
1
2. scale on range
[lowest range).
3. of full scale on range 4. offull scale on range 5.
Sensor multiply noise by 5 on all ranges. For HP 8484A
ZERO DRIFT OF SENSORS (1 hour, offull at temperature afier 24-hour warm-up):
20.1% offill
Sensor Module and
3A/5A/6A scale on lowest range
Sensors.
HP constant for HP 11722A
8481A/l%/lH/2A/2%/2H/ scale on lowest range for HP 6484ASensor.
Decrease by a factor of 10 for each higher range.
Tuned RF Level
POWER RANGE: -127 dBm to 0 dBm, using IF synchronous detector Hz BW).
-100
4
0.01 dBm dB or to 0 dBm, using IF average detector
(30 kHz BW).
FREQUENCY RANGE: 2.5 MHz to 1300 MHz.
DISPLAYED RESOLUTION": digits in watts
0.001 or volts mode. dB in dBm or dBrelative gThe Hp8902A fundamental RF Power measurement units are watts. units.
When using HP Sensor the noise specification may mask the ting on the top RF power range, add the power sensor linearity percent- ages found in the power sensor specifications.
The HP 8902A fundamental Tuned RF Level measurement units are volts. Further internal processing is done on this number to display all other units.
1-22 reo.23SEP86
Model 89024
General Information
1-1. SpccciJicalions
(4
of
7)
Tuned RF Level, continued
RELATIVE MEASUREMENT ACCURACY (at constant
+
RF range-to-range error noise error
2 1 digit.
+
+
IF range-to-range error frequency drift error
+
DETECTOR LINEARITY
For IF Synchronous Detector:
20.007 dB/dB change, but not more than
0
Y
.. ,
, , , , , , & , * .
0
40 30 20
Tuned RF Level Ranges (IF Synchronous Detector)
10 0 -10 -20
, ,
+a 4 -50 -60 -70 do -90
LM lam1
N0tsD.sM.d
, , , , ,
I
-1m
-110 -120 -130
-la
Tuned RF Level Ranges (IF Average Detector) Typically <+.0.004
<20.01 dB/10 dB change.
For IF Average Detector (O'C to +35"C):
20.013 dB/dB change, but not more than
20.04 dB/10 dB change.
Typically <20.008 dB/dB change and
<a0.02 dB/lO dB change.
IF RANGE-TO-RANGE ERROR (see Tuned RF Level range plot)13:
20.02 dB/IF range change, IF
RF RANGE-TO-RANGE ERROR ranges dB/IF range change, IF ranges
1
6 through and 7.
5.
20.04 dB/RF range change (Tuned RF Level only).
20.06 dB/RF range change, RF Power to Tuned RF
Level.
FREQUENCY DRIFT ERROR:
2
0.05 dB/kHz frequency drift from center of IF (using IF synchronous detector).
NOISE ERROR: 20.18 dB for levels <-120 dBm, or for levels <-I10 dBm if Special Function 1.9 is selected.
INPUT SWR:
<1.18, at HP 8902A RF input, RF range 1 and 2.
<1.40, at HP 8902A RF input, RF range 3.
<1.33, at HP 11722A RF input, RF range 1 and 2.
<1.50, at HP 11722A RF input, RF range 3.
<1.33, at HP 11722A RF input, RF range 3 with Special
Function 1.9.
Supplemental Characteristics:
ABSOLUTE LEVEL MEASUREMENT ACCURACY A T
LOW LEVELS (at constant temperature and after RF range calibration is completed)'2:
Absolute level measurement accuracy is a function of the RF Power and Tuned RF Level measurement accu- racy. Product Note 8902A-1 explains how both of these measurements affect absolute level measurement accu- racy. For a source with an output SWR of1.7 and level of -110 dBm the typical absolute level measurement accuracy is 0.46 dB rss and 1.02 dB worst case.
IF FREQUENCY: 455 kHz.
ACQUISITION TZME: <4 seconds, 2-110 dBm.
<lo seconds, 1-127 dBm.
RESPONSE TIME (responding to changes in level of an acquired signal]: <2 seconds, 2-1 10 dBm.
<5 seconds, 2-127 dBm.
DISPLAYED UNITS: Watts, dBm, dB,e,al,ve, mV, pV, dB V, dB mV, dB pV. volts,
IL
0
0
40
-
5
E y) g t.12 t.10 t.08 r
B -
~ & f n a & d a b x n l d i u l o IF t.28
5.24
5.22 t.20 t.ia
5.16
5.14
0 10 nwDn?,
,?w
10 0 -10
20
?an/!,
-20
1
.am dB
+a 4
Lowl do laml
-70 do -90 -100 -110 -120 -130 -160
Teslhg a 10 dB/Step Attenuator
30 40 50 Bo 70 80 Sa 100 110
Attenuation (de)
Testing a 1 dB/SteP Attenuator
, , I
HP 8902A RF range and IF range
Attenuation (dB)
The volts. Further internal processing is done other
HP 8902A units. fundamental Tuned RF Level measurement units are on this number to display all
'*Tuned RF Level accuracy will be affected by residual source-under-test. If the residual
30 second period in a 3
FMpeak is >50Hz
FM of the kHz measured over a
BW. Tuned RF Level measurements should be made using the IF average detector (30 kHz BW) by using Special
Function 4.4. The Tuned RF Level measurement sensitivity when using the IF average detector is -100 dBm.
IF Ranges 6 and 7 (see Tuned RF Level range plots) are only used in automatic operation mately -110 dBm for the IF synchronous detector. and below approxi- mately -85 dBm for for Tuned RF Level measurements below approxi- the IF average detector.
1-23
General Information
Model 8902A
1-1.
SpcciJicalions (5 of 7)
Carrier Noise (Options 030-037)
FREQUENCY RANGE: 10 MHz to 1300 MHz.
CARRIER POWER RANGE: $30 dBm to -20 dBm;
12.5 kHz, 25 kHz and 30 kHz filters.
+30 dBm to -10 dBm; carrier noise filter.
DYNAMIC RANGE: 115 dB.
CARRIER RJZJECTION (temp. 135°C): at least 1
>90 dB; for offsets of channel spacing or 5 kHz, whichever is greater.
RELATIVE MEASUREMENT ACCURACY 20.5 dB; levels 2-95 dBc; 12.5 kHz, 25 kHz and 30 kHz filters.
20.5 dB; levels 2-129 dBc/Hz; carrier noise filter.
CARRIER NOISE FILTER:
Filter Noise Bandwidth: 2.5 kHz nominal.
Noise Bandwidth Correction Accuracy (stored in non-volatile memory): e0.2 dB.
Supplemental Characteristics:
ADJACENTIALTERNATE CHANNEL FILTERS:
6 dB Filter Bandwidth:
8.5 kHz, 12.5 kHz adjacent-channel filter.
16.0 kHz, 25 kHz adjacent-channel filter.
30.0 kHz, 30 kHz lcellular radio) alternate- channel filter.
TYPICAL NOISE FLOOR: -150 dBc/Hz, 0 dBm carrier power level. For System noise performance add LO contribution.
12.5 kHz Filter Shape
25 kHz Filter Shape and CEPT Specification
1-24
- 6 - 4 - 2 0 2 4 6 8 1 0 1 2 1 4 1 6 1 8 2 0
Relative Frequency (kHz)
~
30.0 kHz Filter Shape
-
-30
-40
0
%
-50
-60
0
-10
-20
-70
-80
-90
-12-8 -4 0 4 8 12 16 20 24 28 32 36 40
Relative Frequency (kHz)
-6 -4-2 0 2 4 6 8 10 121416 1820222426
Relative Frequency (kHz)
Carrier Noise Filter Shape
- 2 - 1 0 1 2 3
Relative Frequency
4
(kHz)
5 6
Model
8902A
1-1. Specifications
Measurement
Absolute (Using an HP 11722A
Sensor
Relative
0
RanQe dBm to
-100 dBm
-100.001 dBm
-120.000 dBm to
0 dBm to
-100 dBm
-100.001
-120.000 dBm to dBm
Accuracy
20.005
20.120 dB/lO dB step dB
2
1 digit
20.050 d.120 dB
2 digit
20.005 dB/lO
20.015 dB 2 dB step
1 digit
20.050 dB/10
20.015 dB step dB
2 1 d i d
2
3 0
E m^
2.
2.20
2.26
2.24
5
2.22
g
2.20
2
2.10 t.16
2 2.14
:
2 2.10
2.08
2.06
2 .02
0 10 20 30 40 50 60 70 80 90 100 110
Level (dBm)
(See Tuned RF Level for other specifications.)
Supplemental Characteristics:
MEASUREMENT TIME: 10 to 30 seconds. a
Option 050 specifications are warranted when using a Hewlett-Packard synthesized source with less than
3
100
30
FM measured in
General Information
rev.24A UG8 7 1-24.1
Model 8902A General Information
Accuracy
23 counts of least-significant digit k0.02 HZ
Internal Reference Accuracy t
(3
HZ
Internal Reference Accuracy kHz
20.2 low-pass filter inserted)
Accuracy
23
2 of least-significant digit
Internal Reference Accuracy
20.02 HZ
=Internal Reference Accuracy
Audio RMS Level
1-1. Spcxjjications (6 of7)
Frequency
>1 kHz
5 1 kHz
5 3 kHz
Modulation (Peak)
AM 210%
FM 21.0 kHz
&M 21.5 radians
AM
FM 21.0
&M
210%
21.5 kHz radians
1.5%5AM<10%
0.15
<1 .O kHz
0.15 radianl&M
4 . 5 radians
DISPLAY RANGE: 0.01% to 100.0% (-60.00 dB to
DISPLAYED RESOLUTION: 0.01% or 0.01 dB.
ACCURACY: 21 dB of reading.
0.00 dB).
SENSITIVITY:
Modulation: 0.15 kHz peak FM, 1.5% peak AM or
0.6 radian peak 4M.
External: 100 mVrms.
RESIDUAL NOISE AND DISTORTION17:
0.3% (-50 dB), temperature <4O0C.
Supplemental Characteristics:
MEASUREMENT 3 dB BANDWIDTH: 20 Hz to 50 kHz.
DETECTION: True rms.
MEASUREMENT RATE: 1 reading per second.
AUDIO INPUT IMPEDANCE: 100 kQ nominal.
Frequency
>1 kHz
<1 kHz
FREQUENCY RANGE: 50 Hz to 40 kHz.
VOLTAGE RANGE: 100 m V to 3V.
ACCURACY: 24.0% of reading.
Level llOOmVrm,
1100 mVrms
Supplemental Characteristics:
FULL RANGE DISPLAY: .3000V, 4.000V.
AC CONVERTER: True-rms responding for signals with crest factor of13.
MEASUREMENT RATE: 2 readings per second.
AUDIO INPUT IMPEDANCE: 100 kO nominal.
Audio Distortion
FUNDAMENTAL FREQUENCIES: 400 Hz 25% and
1 kHz 25%.
MAXIMUM EXTERNAL INPUT VOLTAGE: 3V.
Audio Filters
DE-EMPHASIS FILTERS: 25 ps, 50 ps, 75 ps, and 750 ps.
De-emphasis filters are single-pole, low-pass filters with 3 dB frequencies of 6366 Hz for 25 ps, 3183 HZ for 50 ps, 2122 Hz for 75 ps, and 212 Hz for 750 ps.
Hz 50 HIGH-PASS FILTER (2 pole]:
Flatness: <I% at rates2200 Hz.
300 Hz HIGH-PASS FILTER (2 pole):
3
Flatness: <I% at rates 21 kHz. kHz LOW-PASS FILTER (5 pole):
Flatness: <I% at rates I 1
15 kHz LOW-PASS FILTER (5 pole):
Flatness: <I% at rates 110
>20 kHz LOW-PASS FILTER (9 pole Bessel)":
Flatness: <I% at rates kHz.
Supplemental Characteristics:
DE-EMPHASIS FILTER TIME CONSTANT
ACCURACY: 23%.
HIGH-PASS AND LOW-PASS FILTER 3 dB CUTOFF
FREQUENCY ACCURACY: t
>20 kHz LOW PASS FILTER 3 dB CUTOFF
FREQUENCY: 100
<1%. kHz nominal.
OVERSHOOT ON SQUARE WAVE MODULATION'8:
With the low-pass and high-pass audio filters used to stabilize fre- quency readings.
For demodulated signals. the residual noise generated by the HP 8902A must be accounted for in distortion measurements (i.e.. residual AM. FM or 4M.)
The >20 kHz low-pass filter is intended for minimum overshoot with square wave modulation. rev.24AUG87 1-25
General Information
1-1.
SpecQicalions
(7 of 7)
RF Input
FREQUENCY RANGE: 150 kHz to 1300 MHz.
OPERATING LEVEL:
Minimum
Operating Level
Maximum
Operating level
Frequency Range
150 kHz-650 MHz
Supplemental Characteristics:
TUNING:
Normal Mode: Automatic and manual frequency entry.
Track Mode: Automatic and manual frequency entry, fc 210 MHz.
Acquisition Time (automatic operation):
-1.5 seconds.
INPUT IMPEDANCE: 50Q nominal.
MAXIMUM SAFE DC INPUT LEVEL: 5V.
HP
Model 8902A
8902A Rear Panel Inputs/Outputs
Supplemental Characteristics:
FM OUTPUT: 10 pole). k22 impedance, -9V to 6V into an open circuit: -6V/MHz, dc coupled, 16 kHz bandwidth [one
AM OUTPUT: 10 kQ impedance, -4V to OV into an open circuit, -8 mV/%, dc coupled, 16 kHz bandwidth [one pole).
RECORDER OUTPUT: DC measured results, 1 kQ voltage proportional to the impedance, OV to 4Vfor each resolution range into an open circuit.
IF OUTPUT: 5022 impedance, 150 kHz to 2.5 MHz,
-27 dBm to -3 dBm.
10 MHz REFERENCE OUTPUT: 50Q impedance, TTL levels [OV to >2.2V into an open circuit). Available only with Option 002 1 X1O-s/day internal reference.
10 MHz REFERENCE INPUT? >500R impedance,
LO INPUT (Option 003): 5022 impedance, -1.27 MHz to
1301.5 MHz, 0 dBm nominal.
RF SWITCH REMOTE CONTROL OUTPUT: Provides output signals necessary to remotely control either an
HP 3331 lB/C Option 01 I or an HP 8761A RF switch.
FREQUENCY OFFSET MODE REMOTE CONTROL
OUTPUT: TTL high output if in frequency offset mode
[Special Function 27.1 or 27.3) with an external LO frequency >O, TTL low output for all other cases.
General Specifications
TEMPERATURE: Operating: O°C to 55OC.
Storage: -55OC to 75OC.
REMOTE OPERATION: HP-IB; all functions except the line switch are remotely controllable.
HP-IB COMPATIBILITY (defined in IEEE 488-1978):
SH1, AH1, T5, TEO, L3, LEO, SR1, RL1, PPO, DC1, DT1,
CO, El.
EMI: Conducted and radiated interference is within the requirements of VDE 0871 (Level B), and CISPR publication 11.
POWER 100,120,220, or 240V (+5%, -10%); 48-66 Hz;
200 VA maximum.
WEIGHT Net 23.6 kg. (52 lb.); Shipping 31.4 kg (69 lb).
DIMENSIONS: 190 mm.
16.8" X 21.7").
H
426 mm. W
X 551 mm. D
HP SYSTEM I1 MODULE SIZE: 177.0 H
X 1 MW 497.8
D.
External reference accuracy affects accuracy of all measurements
1-26 rev.24A
UG87
Model 8902A
Instrument
AM/FM Test
Source
General Information
Table 1-2. Rccornmcndcd Test Eqiripment
(I
of 4)
Critical Specifications
Carrier Frequency: within range 10 to 1300 MHz
Output Level:
<-72 d E at 12.5 MHz carrier with 12.5 kHz deviation and -30 kHz rate
<-72 dB at rate
>-20
FM Deviation: 400 kHz peak maximum
FM Distortion:
400 dBm
MHz carrier and 400 kHz deviation at 4 0 0 kHz
FM Flatness: i O . l % from 20 Hz to 100 kHz rates f0.25% to 200 kHz rates
CW Residual FM: <3 Hz rms in a 50 Hz to
560 MHz
Incidental AM: <O.O8% AM at 100 MHz with <50 kHz peak deviation and 1 kHz rate in a 50 Hz to 3 kHz bandwidth
AM Depth: 5% to 99%
AM Distortion:
<-66 dB at <50%
3
AM at 20 Hz to 100 kHz rates
<-60 dB at <95% AM at 20 Hz to 100 kHz rates
AM Flatness:
&0.1% from 50 Hz to 50 kHz f0.25% from 20 Hz to 100 kHz
Incidental (PM: kHz rate in
<0.008 a 50 Hz to f0.1% at <95% AM f0.2% at <99% AM
3
Residual AM: <0.01% rms in
AM Linearity: kHz bandwidth a 50 Hz to 3
50% AM at kHz bandwidth a 1
Suggested
Model
HP 11715A
HP 8491A
Option 03
Attenuator,
3
(2 dB required)
~~~~ ~
Attenuator,
6 dB
Frequency: 30 MHz
SWR
(Used as alternate equipment.)
Audio
Analyzer
Frequency Range: 0.15 to 1300 MHz
SWR Maximum: 1.2
Attenuation Accuracy: M.4 dB
~~ ~
Fundamental Frequency Range: 20 Hz to 100 kHz
Distortion Range: -70 dB minimum
Distortion Accuracy: k2
Low-Pass Filters: 30 and 80 kHz
Oscillator Level: 3V maximum into
Oscillator Distortion: < -70 dB
Oscillator Frequency Accuracy:
600R
*C=ODerator's hecks: P=Perforrnance Tests; A=Adiustments; T=Troubleshooting
HP 8491A
Option 06
HP 89036
General Information nable 1-2. Recommended Test Equipment (2 of 4)
Instrument
VLpe
Audio
Synthesizer
Critical Specifications
Frequency Range: 20 Hz to 400 kHz
Output Level: +16 dBm
@On)
Frequency Accuracy: 40.1%
Attenuator Accuracy: 40.1 dB from f0.07
0 to 20 dB
Level Flatness: dB from 20 Hz to 200 kHz
Distortion: i-50 dB from 20 Hz to 200 kHz
Suggested
HP 3336C
Option 005
Computing
Controller
HP-IB compatibility as defined by IEEE Std 488 and the identical
ANSI Std MC1.l: SH1, AHl, T2, TEO,
DTO, and C1, 2, 3,4, 5.
L2, SRO, PPO, DCO,
Model 8902A
HP 9825A and
HP 98034A and
HP 98213A or
HP 858 Option 007
CF,T
Digital
Multimeter
DC Range: 0 to 50V
DC Accuracy: f0.01% at 1 V
AC Range: 0 to lOOV
AC Accuracy: f0.01% at 2V and 2 kHz
Ohms Range: 0 to 1 MR
Ohms Accuracy: f l %
~~
Divider
Probe
(2 required)
Divider Ratio: 1O:l
Input Impedance: 1 MR
Input Capacitance: i l 0 pF
Extender
Cable
Frequency
Stand a r d
No substitution is recommended.
Accuracy: f O . l ppm recommended
Oscilloscope Bandwidth:
Sensitivity: less
5 than 3 dB down 0 to 100 MHz mV per division minimum
Input Impedance: 10 M n and 500
Triggering: External and Internal
Piston
Attenuator
Accuracy: f(0.005 dell0 dB
+
(Used as alternate equipment.)
0.03 de) at 30 MHz
I
*C=Operator’s Checks; P=Performance Tests; A=Adjustments; T=Troubleshooting
7-
HP 1740A
I
C A T
1
1-28 rev.01 MAR88
Model 8902A General Information
1-2. Recommended Tesf Eqiiipmenf (3 of 4)
~ Instrument
Type
Power Meter or
Power
Reference
Critical Specifications
Power Range: 1 mW
Frequency Range: 50 MHz
SWR: 1.05
Accuracy: f0.5%; NBS calibrated
Power Output: 1.00 mW, factory set to f0.7%, NBS calibrated
Accuracy: tt(1.2% worst case +0.9% rss) for one year; 0 to 50' C
Power Supply
~
Output Range: 0 to 25 Vdc
HP
HP 478A
Option H75
HP 435A
Option KO5
HP 6215A
Range
Calibrator
Calibration Functions: outputs corresponding to power displays of
10 pW, 100 pW, 1 mW, 10 mW, and 100 mW
Calibration Uncertainty: ~t0.25% in all ranges
HP 11683A
RF
Spectrum
Analyzer
Frequency Range: 0
Input Level:
*lo to dBm
Display Range: 60 dB
2 GHz maximum
HP 8559A and
HP 182T
HP 11 722A Sensor
Module
Service
Accessory
Kit
Compatible with HP 8902A
Input SWR:
4.3, at RF Input, RF Ranges 1 and 2
4.5, at RF Input, RF Range 3
11.3, at RF Input, RF Range 3 with Measuring Receiver's
Soecial Function 1.9
No substitution recommended. HP 08901 -60287
HP 8640B
Options 001 and
002
C,P,A
T
Signal
Generator
Frequency Range: 0.5 to 1100 MHz
Output Level:
$19 dBm maximum to 500 MHz
$13 dBm maximum to 1100 MHz
Output Level Accuracy: fl
Frequency Accuracy: *l dB
Frequency Resolution: 1 kHz
Modulation Capability: AM and FM
AM Depth: 0 to 95%
AM Accuracy: &lO%
FM Range: 0 to 400 kHz peak deviation
FM Accuracy: &10%
*C=Operator's ~~ ~ hecks: P=Performance Tests; A=Adiustments; T=Troubleshootinq rtv. IFERRUA RY86 1-29
General Information instrument
Type
Signature
Analyzer
1-2.
Recommended Tesl Eqiripmenf (4 of 4)
Critical Specifications
External Count Range: to 15 MHz
Because the signatures documented are unique to a given signature analyzer, no substitution is recommended.
Suggested
Model
HP 5005A
Model 8902A
Use*
T
Step
Attenuator
Step Accuracy: M.01 dB between 10 and 20 dB at 50 MHz HP 355D
Option J25
P
SWR
Bridge
Frequency Range: 150 kHz to 1300
Impedance: 50a
Directivity: A 0 dB
Connectors: Type-N
MHz Wiltron 60N50 P
1-30
Model 8902A General Information
Table I-3. Recommended Test Accesories
Accessory Type'
I
Recommended Part
Adapter (Type N Male to BNC Female connectors)
Capacitor, 620 pF
IC Extender Clip, 16 Pin
Resistor, 2150fIl% 1/4W
Tee (Coaxial, BNC, one Male and
50QLoad (Male, BNC, coaxial)
Adjustment Tool two Female connectors)
HP 1250-0067
HP 01 60-3536
HP 1400-0734
HP 0757-0422
HP 0757-0274
HP 0698-0084
HP 0698-3155
HP 1250-0781
HP 1250-0207
HP 8710-0772
I
'Accessories listed in this table are only those not already contained in the Service Accessory Kit HP 08901-60287
Model 8902A Installation
I N
Section 2
STALL AT1 0 N
2-1. INTRODUCTION TO THIS SECTION
This section provides the information needed to install the Measuring Receiver. Included is information pertinent to initial inspection, power requirements, line voltage selection, power cables, interconnection, operating environment, instrument mounting, storage and shipment. This section also contains a procedure for setting the internal HP-IB talk and listen address switches and a procedure for removing the pull-out cards.
2-2. INITIAL INSPECTION
To avoid hazardoirs electrical shock, do not perform c$ectrical iesls when lhcre art' signs of' shipping damage to any porfion panels, mcters).
oj
the outm enclositre (covers,
Inspect the shipping container for damage. If the shipping container or cushioning material is damaged, it should be kept until the contents of the shipment have been checked for completeness and the instrument has been checked mechanically and electrically. Procedures for checking electrical performance are given in Section 4. If the contents are incomplete, if there is mechanical damage or defect, or if the instrument does not pass the electrical performance test, notify the nearest
Hewlett-Packard office. If the shipping container is damaged, or the cushioning material shows signs of stress, notify the carrier as well as the Hewlett-Packard office. Keep the shipping materials for the carrier's inspection.
2-3. PREPARATION FOR USE
Power
Requirements
To avoid the possibility o j hazardoirs cdcvtrical Jhock, do no1 opcwilc' lhiJ inJlrirmcnt than 66 at
Hz. linc volfages greatcr than 126.5 Vac wirh lint1 jkeqirtvcirs
Lcakagc citrrents at grcwlcr thcw linc sdtings may cxctvd 3.5 mA.
The Measuring Receiver requires a power source (+50/0 to -10%) to
- only). Power consumption is 200 VA maximum. of 100, 120, 220, or 240 Vac, 48
66 Hz single phase. Option 004 also operates from 48 to 440 Hz single phase, 120 Vac, (+5% to
2- 1
Installation Model 8902A
2-2
I
Operating voltage is shown in module window.
Selection of Operating Voltage and Fuse Replacement
1. Open cover door, pull the FUSE PULL lever and rotate to left. Remove the fuse.
2. Remove the Line Voltage Selection Card. Position the card so the line voltage appears at top-left corner. Push the card firmly into the slot.
3. Rotate the FUSE PULL lever to its normal position. Insert a fuse of the correct value
Close the cover door. in the holder.
Figure 2-1. Line Voltagc and Fitse St&>ction lWAR”Gj
This is a Safi‘ty Class I prodiict (that is, providcd with a protcclivcl eurth tcrmi- nal). A n iinintcrriiptihl~ safiVy carth groirnd miist ion. providc>d,ji-orn ths main power soiirce to thr proditcl inpiit wiring terminal.,, powcr cord, or .siipplid powcr the prodiict miist hr opcv-at hc cord set. Whencwr it is likcly ihat thz protection has hwn impaird, mudti inopcwtivc and he secirrcd uguinst uny iitiintc~ndc~l
If‘ this insfriimcnt is to hc cncrgi=cd via an cxtcrnal aiitotrun.~f~rmc~r, siirc thc aiitotran,~for~n~~r’.s
Of’thr powcr soitrcx common terminal i.s conncc-lcd to thc twlhcd polc
1 Model 8902A
;z
250V
I
250V
I
250V
125V fi
oov
(Same plug as above)
250V 8120-21 04 G T =
E
8120-4753
8120-4754
250V
Installation
Table 2-2. AC Power Cables Availiable
Cable
Number
8120-1351
8120-1703
Plug
Description
I
0 90°/STR BS1363A*
Cable
Length
(inches)
90
90
8120-1369
81 20-0696
STR/90°
Cable
Color
Mint Gray
Mint Gray
Gray
Gray
1
In Country
United Kingdom,
Cyprus, Nigeria,
Rhodesia,
Singapore
Austrailia,
New Zealand
81 20-1 689
8120-1692
81 20-1 378
8120-1521
8120-1751
STR/STR
STR/STR
STR/90°
1959-24507
STR/QOo
90
90
90
Mint Gray
Mint Gray
Jade Gray
Jade Gray
Jade Gray
Dark Gray
Dark Gray
Gray
East and West
Europe, Saudi
Arabia, Egypt,
(unpolarized in many nations)
United States,
Canada, Mexico,
Phillipines, Taiwan
U.S./Canada
~
Japan only
-I
I
Gray
Gray
Black
Canada
~ 250V r
250V
8120-2956
8120-2957
8120-3997
90°/900
STR/STR
8120-4600
Gray
Black
Gray t
~~
250V
Jade Gray
(Systems Cabinet Use)
59
Jade Gray
Jade Gray
Jade Gray
Part number shown for plug is industry identifier for plug only. Number shown 1 cable
is HP Part Number for complete
I
Installation Model 8902A
Line Voltage and Fuse Selection
BEFORE PLUGGING THIS INSTRUMENT into the he siirc thc corrtw volfagc and jiisc havc hwn sc'k.cfcw'.
Mains
(linc) volragc,
Verify that the line voltage selection card and the fuse are matched
Figure 2- I, Liiic Volfagc and Fiisc Sclcwion. to the power source. Refer to
Fuses may be ordered under HP part numbers 2110-0083, 2.5A (250V normal blow) for 115 Vac operation and 21 10-0043, 1.5A (250V normal blow) for 230 Vac operat.ion.
Power Cables
L\NARN'NGI
BEFORE CONNECTING THIS INSTRUMENT, thc profwfivc carfh tcrmi- na1.s of this insfriimcnl miisf hc conncctcd to fhc protcwivc condiictor of' the
(Muim) powrr cord. The Mains plug shall only he inserttw' in u providtd wirh
a
protscvive curlh cvnlact. The proteciivc con di ictor (groi i ii ding). action sockcf miis[ ouikv not hc ncgatcd by the itse q[ an cxixlensioii cord (power cahlc) tviihoiii u profcciive
This instrument is equipped with a three-wire power cable. When connected to an appropriate ac power receptacle, this cable groiinds the instrument cabinet. The type of power cable plug shipped
with each instrirment depends on the country of destination. Refer to Table 2-1 for the part numbers
of the power cables available.
HP-IB
Address
Selection
The HP-IB address switches are located within the Measuring Receiver. The switches represent a five-bit binary number. This number represents the talk and listen address characters which an HP-IB controller must generate. In addition, two more switches allow the Measuring Receiver to be set to talk only or to listen only.
2-4
In the Measuring Receiver, the HP-IB talk and listen addresses are selectable by an internal switch
This address can be read by selecting BUS ADRS (Blue
procedure explains setting of the switches. Refer to Table 2-2 for a listing of the talk and listen
addresses. In the factory, the address is set for a talk address of
(period). In binary, this is 01 110; in decimal it is 14.
Key,
"N"
LOCAL). The following and a listen address of "."
1. Disconnect the line (Mains) power cable.
2. Remove any HP-IB cables or connectors from the HP-IB connector.
3. Remove the Measuring Receiver's top cover
Model 8902A Installation a. Remove the two plastic feet from the rear of the top cover by removing the pan-head
Pozidriv screw within each foot. b. Unscrew the Pozidriv screw at the center of the rear edge of the top cover. This is a captive screw and will cause the top cover to pull away from the front frame. c. Lift off the top cover.
4. Locate tlie HP-IB address switch on the A14 Remote Interface Assembly near the front right of the instrument. The A14 assembly may be recognized as having one brown and one yellow printed circuit board extractor.
Figure 2-2. Thc
Thc Addrc>ss Shown
HP-113 Swilch Shown
(IS
Si>[ iJ 01110 in Uinury (14 in Dvcimul) Wilh Dolh Tulk Only and Lisicn Only O/r
5. Use a pencil to set the switches to the desired HP-1B address and Talk Only (TON) or Listen
Only (LON) condition. The switch is illustrated switch (marked with a “5”) is the most significant address bit toward the printed circuit board places it are both set to switch are measurement in
Facing the board, the left hand
(A5
Setting a switch in its “1” position. If the TON and LON switches
“I”, the Talk Only setting will override. If the address switches and the TON all set to “l”, the Measuring Receiver will output one byte (the status byte) each cycle. (Setting all switches to “ I ” defeats HP-IB operation.)
6. Reinstall the top cover by reversing the procedure in previous step 3.
7. Connect the line (Mains) power cable to the Line Power Module and reconnect the HP-IB cable to the HP-IB connector.
8. To confirm the address, turn on the instrument and select BUS ADRS (Blue Key, LOCAL).
To confirm a talk only or listen only setting, key in 21.0 SPCL. The display shows a binary
2-5
Installation Model 8902A
number in the form AAAAA.TLS where AAAAA is the HP-IB address in binary and T,L, and
S indicate talk, listen, and service request status.
-
-
0
0
0
0
-
-
0
0
0
0
-
-
0
0
0
-
-
0
0
S
-
A I Character c
0
0
I
0
Talk
Address
@
A
C
D
Listen
Address
Character
SP
!
#
$
Decimal
Equivaleni
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
P
Q
R
S
T
J
K
L
M
N
0
E
F
G
H
I
O/O
&
I
0
(
)
+
16
17
18
19
20
15
0
0
0
0
0
0
0
0
0
0
U
V
W x
Y
21
22
23
24
25
0
0
0
0
0
0
0
Z
[
\
h
Invalid
-
>
Invalid
26
27
28
29
30
31
Interconnections
Interconnection data for the Hewlett-Packard Interface Bus is provided in Figure 2-3.
Mating Connectors interface Connector screws are metric.
The HP-IB mating connector is shown in Figure 2-3. Note that two securing
Installation Model 8902A
SHOULD BE GROUNDED
NEAR TERMINATION
OF OTHER WIRE OF
TWISTED PAIR
StGNAL GROUND
P/O TWISTEO PAIR WITH 11
P/O TWISTED PAIR WITH 10
P/O TWISTED PAIR WITH 9
P/O TWISTED PAIR WITH 8
P/O
P/O
TWISTED PAIR WITH 7
TWISTED PAIR WITH 6
REN
Dl0 8
DIO 7
DIO 6
DIO 5
ISOMETRIC
- x 0.6
SHIELD -CONNECT TO
ATN
SRO
IFC
NOAC
NRFD
DAV
EARTH
GROUND
EO1
DIO 4
Dl0
DIO
3
2
DIO 1
24-PIN MICRO-RIBBON
(SERIES 57) CONNECTOR
Logic Levels
The Hewlett-Packard Interface Bus logic levels are and the false (0) state is 2.5 Vdc to +5 Vdc.
TTL compatible, that is, the true (1) state is 0.0 Vdc to +0.4 Vdc
Programming and Output Data Format
Refer to Section 3 "Operation".
Mating Connector
HP 1251 -0293; Amphenol 57-30240
Mating Cables Available
HP 10833A, 1 meter (3.3
HP 10833C 4 meters (13.2 e.), ft.)
HP 10833D. 0.5 meters (1.6 ft.)
Cabling Restrictions
1. A Hewlett-Packard Interface Bus system may contain no more than 2 meters (6.6 instrument. ft.) of connecting cable per
2. The maximum accumlative length of connecting cable for any Hewlett-Packard Interface Bus system is 20 meter
(65.6 ft.). rev.
15MA
Figure 2-3. Hewlett-Packard Interface Bus Connection
2-7
Installation Model 8902A
50R
Connectors Coaxial mating connectors used with the Measuring Receiver should be the
BNC male connectors or 50a Type-N male connectors that are compatible with those specified in US MIL-C-39012.
The application note, “Principles of Microwave Connector Care” (HP part number 5958-7442) can help you improve measurements and reliability. Suggestions in the application note will help you get the best performance from all microwave connectors. It will show what to look for when cleaning and inspecting connectors (in order to preserve their precision and extend their life) and how to make the best possible microwave connections (improving the accuracy and repeatability of all yoiir measurements).
Operating Environment
The operating environment should be within the following limitations:
Temperature
Humidity
Altitude
.......................................
.................................. .4570
-0°C to +55”C
~ 9 5 % meters (15 000 feet)
Bench
Mounting
The instrument cabinet has plastic feet and fold-away tilt stands for convenience in bench operation. (The plastic feet are shaped to ensure self-aligning of the instruments when stacked.) The tilt stands raise the front of the instrument for easier viewing of the front panel.
Rack Mounting
[WARNING]
The Measiiring Rcccivc>r is hc>avy,jbr exercised when lijiing rack rnoiinting. siz-e (23.6 kg, 52 lh). Caw mirsl hc to avoid pusonul injiiry.
Us12 eqiiipment slides when
Rack mounting information is provided with the rack mounting kits. If the kits were not ordered with the instrument as options, they may be ordered through the nearest Hewlett-
Packard office. (Refer to paragraph 1-8, A ddi(ioirtr1 Gqiiipment In$mnation under Mcchunicul
Eqiiipmenf A vailahlc. Before rack mounting the Measuring Receiver, the Opcrating lnjhrma- tion pull-out tray (attached to the bottom of the instrument) must first be removed. To remove the pull-out card assembly, refer to the procedure that follows.
Removal
and
Installation of Operating Information Pull-Out Cards
Steps for Removal Follow the procedure below to remove the OptIraling /nJbrma/ion pull-out card assembly:
1. Remove the two front feet of the instrument.
2. Remove the Operating Information tray assembly by sliding the tray toward the rear of the instrument and then down.
3. Remove the information cards by bowing them slightly in the middle and pulling it straight up (away from the tray).
2-8
Model 8902A Installation
Steps for Installation Follow the procedure below to reinstall the Operaling pull-out card assembly:
Znjormalion
1. Install the information card by bowing it slightly in the middle and carefully guiding the edges into the plastic guide slots near the front of the tray.
2. Push the information card all the way into the tray.
3. Place the information tray assembly between the rear feet of the instrument and slide it forward until the tabs are locked under the rear feet.
4. Replace the front feet of the instrument.
2-4. STORAGE AND SHIPMENT
Environment
The instrument should be stored in a clean, dry environment. The following environmental limitations apply to both storage and shipment:
Temperature
Humidity
Altitude
......................................
................................ .I5 300
-55°C meters (50 to +75OC relative
000 feet)
Packaging
Original Packaging Containers and materials identical are available through Hewlett-Packard offices. If the instrument is being returned to Hewlett-
Packard for servicing, attach a to those used in factory packaging tag indicating the type of service required, return address, model number and full serial number. Also mark the container FRAGILE to assure careful handling. In any correspondence refer to the instrument by model number and full serial number.
Other Packaging The following general instructions should be used for re-packaging with commercially available materials:
1. Wrap the instrument in heavy paper or plastic. (If shipping to a Hewlett-Packard office or service center, attach a tag indicating the service required, return address, model number and full serial number.)
2. Use a strong shipping container. A double-wall carton made of 2.4 MPa (350 psi) test material is adequate.
3. Use enough shock-absorbing material (75 to 100 mm layer; 3 to 4 in.) around all sides of instrument to provide firm cushion and prevent movement in the container. Protect the front panel with cardboard.
4. Seal the shipping container securely.
5. Mark the shipping container FRAGILE to assure careful handling.
WV.
16JUNE86 2-9
Model 8902A Operation
Section
3
OPE RATION
3-1. INTRODUCTION TO THIS SECTION
This section provides advanced operating information for the Measuring Receiver. Included in this section are descriptions of all front- and rear-panel controls, connectors, and indicators, remote and local operator’s checks, operating instructions, and operator’s maintenance.
Local Operation Section
Information regarding front-panel operation of the Measuring Receiver is provided in the sections described in the following paragraphs. To most rapidly learn the basic operation of the instrument, refer to the separate Basic Opcrafion and Applicaiion Giridc and/or perform the
Once familiar with the general operation of the instrument, use the
Opcraior’s Checks.
Dduilcd Opcraiing Inslriicliom for the most in-depth and complete information on operating the Measuring Receiver.
Remote Operation Section
The Measuring Receiver is capable of remote operation via the Newlett-Packard lnterface Bus (HP-
IB). Provided in this section are instructions pertinent to HP-IB operation including all specific considerations and instructions (including capabilities, address formats, input and output formats, the status byte, and service requests). At the end of the discussion is a complete summary of all codes and formats.
HP-IB information concerning remote information also appears in several other locations. Address setting is discussed in Section 2, a summary of HP-IB codes and output formats appears on the
Operating Iqlormalion pull-out card, and a list of relevant program codes for each function appears in the paragraph, Local Optralion Section
.>
(Detailed Operating Instructions are described above in the
Basic Functional Checks Section
Bahic Fiinc*lional Chccks are simple procedures designed to be performed by the operator. These checks verify the proper operation of the Measuring Receiver’s main functions and HP-IB capabilities. These checks can also be used to familiarize the first-time operator with basic Measuring
Receiver measurements and HP-IB capabilities. Two procedures are provided:
Basic Functional Checks of the Measuring Receiver
This procedure assures that most front-panel controlled fiinctions are being properly executed by the Measuring Receiver. The checks require the use of a sensor module, a signal generator, an oscilloscope, and interconnecting cables and adapters.
Basic Functional Checks
of
the Hewlett-Packard lnterface Bus (HP-IB)
This series of procedures requires only an HP-IB compatible computing controller and an HP-IB interface and connecting cable. The HP-If! FirwcYrultal Chccks assume that front-panel operation has been verified (for example, by performing the Basic J’itnclioual Chcwks).
3- 1
Operation Model 8902A
Detailed Operating Instructions Section
The Dctailcd Opcraf ing Ins/riitlions provjde a complete operating reference for the Measuring
Receiver user. The instriictions are organized into tabbed sections oriented toward specific measurement types. Besides information on the various measurements, the instructions contain individual discussions of nearly all controls, inputs, and outputs. Also included are instructions for using the many user special functions. A guide to using the Detaikd Opcrating ahead of the instructions themselves.
Instructions is provided
Other Sources of Operating Information
Pull-Out Cards
The Oprrating Informalion and Special Fitnction reference sheets attached to the Measuring Receiver by a tray located beneath the front panel.
They contain a
In.formation Piill-Oiit Cards are flexible plastic brief summary of front-panel operation and displays. Also included on the cards is a complete listing of HP-IB codes, data, and error output formats, error codes, and user special functions. The cards show a simplified block diagram for the Measuring Receiver and provide basic instructions for operation.
RF Power and Tuned RF Level Measurement operation. The pull-out cards are intended to be n reference for the user who already has a basic understanding of front-panel
Supplemental Information
Other information, pertinent to operating the Measuring Receiver to its fullest capabilities, are contained in
Op~wting
Swtion I .
1-10) is a fundamental description of what the Measuring Receiver is and how it works. This information supplements the block diagrams provided on the pull-out card and in the Dc.taikd
/n.striic/ion.s.
“Principles of Operation for a Simplified Block Diagram” (in paragraph
“Modulation Basics” (in paragraph 1-1 1) is a discussion about the basis for applying the Measiiring Receiver to various measurement situations. way the
Measuring Receiver makes modulation measurements. All of this information helps to provide a
3-2. OPERATING CHARACTERISTICS
OF
THE MEASURING RECEIVER
The major operating characteristics of the Measuring Receiver are provided in paragraph 1-6,
De~cription,
For information on HP-IB capabilities, refer to Rcmote section in this manual.
3-3.
OPERATOR’S INFORMATION
Fuses
(WARNINGI
For con(iniicd protcvlion u.gain.l.1 ,fire hazard, rcylacc lhc linc jiisc only wilh u s h
250 V norniul hlo w jitsc> qj’ (hc samc ruling. orr -circ*i it ed ji iseh olders.
Do not i i s c rcyaircd j i i ~ c s
The only maintenance the operator should normally perform is the replacement of the primary power fuse located within the Line Power Assembly (A30). For instructions on how to change the
fuse, refer to Figure 2-1, steps
1 and 3.
Fuses can be ordered using HP part number 21 10-0083, 2.5A (250V, normal blow) for 100/120 Vac operation or 21 1.5A (250V, normal blow) for 220/240 Vac operation.
3-2
Model 890214
Time Base
10 MHz
Input and Time Base
10 MHz
Output p v m i q
Do no1 apply grrafcr lhan 2OVpcak (ac
INPUT or damagc to
+ dc) into the instriimenl may resirlt. the TIME BASE 10 MHz
Do not apply grcaler rhan 3 Vdc or greatm than +20 dBm info Cht> TIME
BASE IO M f f z
OUTPUT
or darnage to thc insirirmcnt may rcsirlf.
Operation
Description
Time Base 10 MHz Input. Provides an input for an external 10 MHz time base reference. This input is ac coupled and requires an input signal level greater than approximately 500i2.
0.5 Vpp. The input impedance is
The time-base circuitry of the Measuring Receiver automatically switches when an external time base of sufficient amplitude is applied. to the external time base
When using an external time base reference, the acccuracy of all measurements depends on the accuracy of the external reference. Frequency-related measurements are most noticeably affected by time-base innacuracy.
To determine whether the Measuring Receiver has actually switched in the externally applied time base, select 15.1 SPCL. If an external time base time base is being used, the display will show a is being used, the display will show a
0.
1. If the internal
If the Measuring Receiver is using the internal, Option 002 time base, you can determine whether the time base oven is warm enough to create a stable source by selecting 15.0. The display will show a 0 if the time base oven is adequately warm. The display will show Error 12 if the time base is cold.
To drive several instruments from a single external reference, simply use a BNC tee at the Measuring
Receiver’s TIME BASE 10 MHz INPUT.
If the internal time base fails, an external time base may still be used. Connect the external time base to TIME BASE 10 MHz INPUT, then switch the instrument’s POWER switch to STBY and back to
ON.
Time
Base
10
MHz
Output. (This output is available only with the high-stability reference, Option
002.) Provides an output for the internal 10 MHz reference. The output is a output (OV to greater than 2.2V into an open circuit).
500, compatible
When driven from an external reference, the Measuring Receiver outputs the internal reference (not the external input signal). TIME BASE 10 MHz INPUT provides an input for an external 10 MHz time base reference. This input is ac coupled and requires an input signal level greater than
The input impedance is approximately 500Q.
0.5 Vpp. rev.
I6JUNEY6
3-3
Operation
3-4. TURN-ON PROCEDURE
Bejorc llie Meusiiring Rt.c.c‘iver is switchcd on, all protectivc earth tcrminals, extension cords, aiito-transformers, and deviccs connected conncclcd to a profcctivc> tjarlh socka. A ny inttwiiplion
of
groiindiirg will cairse u polential shock hazard thar coirld injirry. lo it shoidd bt2
[he protective earrh resirlt in pcrsonal
For corrtiniicd protection against fire hazard, replace the line jiise with
250V normal blow fiisc of the same rating. shorl-citwircd jirseholdm.
Do not irse
a
repaired jirses or
Model 8902A
Btforc. rhc Mcasirring Rcwivcr is switched
2-3, P0wt.r Reqiiirements.
on,
il mirst be set to the vollage oJ’ rhc powr soiircc: or damuyc lo the instrirment may r~wilt. RcIfL’r to paragraph
Do
not
apply greater fhan 40V (ac damage lo the instriiment may resiill.
+ dc) to the RF INPUT connector
or
The Measuring Receiver has a standby state and an on state. Whenever the power cable is plugged in, an internal power supply is activated. In instruments supplied with the high-stability reference (Option
002) the supply energizes the internal reference oven. If the Measuring Receiver is already plugged in, set the POWER switch to ON. If the power cable is not plugged in, follow these instructions:
1.
Check that the line voltage setting matches the power source. (See Figure 2-1,
Line Voltage and
Fiise Sckction .)
2.
Check that the fuse rating is appropriate for the line votage used. (See Figure 2-1,
and Firse Selection.) Fuse ratings are provided in the paragraph section.
3. Plug in the power cable.
Linc
Operator’s Muintcwance
Voltage in this
4. Set the POWER switch to ON.
NOTE
When the POWER swifch is approximately 10 seconds
set
to ON, all jront-panel ufrer which the instriiment is indicators lighl jor ready to he operatcd
3-5. INSTRUMENT FEATURES
Front-panel controls, indicators, and connectors are illustrated and referenced to text in Figure 3-1.
The text for this figure describes the various functions of the Measuring Receiver. At the end of each description is a reference to a detailed operating instruction that contains more details on this topic.
Rear-panel features are shown and referenced to text in Figure the rear-panel connections.
3-2. The text for this figure provides a quick reference for rear-panel signal levels and frequencies and also includes the impedances at
The information in parenthesis at the end of each feature summary provides the title of the Dctailcd
Operating Znstriidions relevant to the feature.
3-4 rcv. 1 6 JWhrEY6
Model 8902A
:e
. -
. I
'6
13
34
33
32
31
0 per at i o n
3 4 5 6 7 8
9
1C
3-5
Operation Model 8902A
Front-Panel Features
The following list provides a brief description of each feat.ure. The information in brackets provides the title of the Delailcd for the instructions.
Upcmling 1n.stri~ctions
1. MEASUREMENT keys enable the Measuring Receiver to make and display the selected measurement. [See AM,
Distortion, IF LtwL Tuned R
I:
@M, RF Powcv-, RF
Levi4,
Inflirt
RF I.it>qiiiwcy Error.
Frqirency, Aicdio Frcqirtwcy, A icdio
2. Numeric Display shows measurement results, error codes, or instrument or Special Function status.
3. Display Annunciators indicate the measurement result units. They also indicate that some measurement functions are enabled. All these annunciators are displayed when the Measuring
Receiver is first turned on.
4. AUTOMATIC OPERATION enables the Measuring Receiver to automatically tune and to autorange to make the selected measurement. [See A iifomalic Opwation. ]
5. INSTR PRESET (Blue Key) configures the Measuring Receiver
Inslrirmenl Preset. ] to its power-up condition. [See
6. TRACK MODE
Receiver. [See and AUTO TUNING
RF Frqiitwcy Tuning.]
(Blue Key) select the tuning mode of the Measuring
7. STORE (Blue Key) and RECALL (Blue Key) enable the Measuring Receiver to store and recall up to eight measurement states. [See Storc~/Rc.c.all.]
8. WATTS, pV, mV, and VOLTS keys (all used with the Blue Key) enable selection of different units for level measurements.
9. MHz completes the keyboard entry of frequencies for various functions. This key is also used to complete the entry of frequencies used with
Modc, R1: P0wc.r .I
RF Power calibration factors. [See Rf.’ 1;rcyircwc.y
10. MODULATION OUTPUT/AUDlO INPUT connector provides either an output for the modulation recovered from the RF INPUT connector to be processed by the audio circuitry. The MODULATION OUTPUT annunciators indicate the type of recovered modulation available as the outpiit. The AUDIO lNPUT key selects whether the internally demodulated signal or an external audio signal is to be processed by the
Measuring Receiver’s audio circuitry. [See Modirlation
A irdio Distorlion and Liwl, SINA
D.]
or an input for external audio signals
Oic/pirt/A
irdio Inpiit, A iidio I.iqiwncy,
11. Yo CAL FACTOR (Blue Key) causes the Measuring Receiver to display the current calibration factor for the selected measurement. This key is also used to complete the entry of calibration factors for various functions. [See AIM Culihrutiun, FM Culihruliun, RF Puwur, Tirncd RF Lcvc~l.]
12. DISPLAY FREQ (Blue Key) causes the Measuring Receiver to display the RF frequency that it tuned to last. [See E‘rqircwcy O[/iet Mu&, RI;‘ Powsr Calihrulion Faclor,. ]
13.
14.
SENSOR connector provides the input for the power sensor. [See RF Powcr. J kHz and kHz 4 change the frequency in the increments specified. [See RI: I:rcqitenc*y Ticning.] tuning, or
15. DISPLAY FREQ INCR (Blue Key) causes the Measuring Receiver to display the increment step-size. [See RI; Frtqricnt‘y Ticning.]
16. INPUT couples the RF input signal into the instrument. [See RF Inpiit Fwqi/cncy.]
I /.
SPCL completes entry of Special Function codes that access additional instrument operations.
Without a preceeding numeric entry, the SPCL key causes a display of the status of Special
Functions 1 through IO. [See Spc~.ial f*’i/nctiuns.
3-6
Model 8902A Operation
18. (-) (Blue Key) enables inpiit data to be entered as a negative value,
19. RANGE
Hold. 3
HOLD fieezes the current ranges being used by the Measuring Receiver. [See Range
20. Blue Key is a shift key that enables some keys to have two different functions. Any function printed in blue can be selected when the key associated with it is pressed after the Blue Key.
(The Blue Key flashes at the ciirrent measurement rate whenever it is pressed.)
21. DISABLE ERROR (Blue Key) disables Error 01 through Error
Control. J
04. [See Error McsJage Disablt.
22. LOG/LIN causes measurements to alternate between logarithmic and linear units. [See Rafio and Log/Lin.]
23. dB EXT ATTEN (Blue Key) enables level measurements to be offset with external attenuation or gain. [See External AItcniiation.1
24. RATIO and PREVIOUS RATIO (Blue Key) cause the current measurement to be compared to a reference. [See Ra/io and Log/Lin.]
25. Opcraling Infurmation pull-oiit cards are quick operating references that list Special Function,
HP-IB, and Error codes, show a simplified block diagram for the Measuring Receiver, and provide basic information for R F Power and Tuned R F Level operation.
26. DETECTOR keys select the audio detector used to measure the modulation. [See Airdio
Dctiv/or.s, A itdilio Dislorlion and 14rvel, SINAD. ]
27. 1 kHz DISTN (Blue Key) and 400 Hz DISTN (Blue Key) enable the Measuring Receiver to make audio measurements o n either 1 kHz or 400 Hz audio signals. [See A itdio Dis/or/ion and
Lrvd, SINAD. ]
28. CALIBRATION AM/Fh! OUTPUT makes available a precisely modulated signal used to improve the Measuring Receiver's AM or FM accuracy. [See A M Calibration, FM Calibration. J
29. CALIBRATE and SAVE CAL (Blue Key) enable the Measuring Receiver to calibrate and save the resulting calibration factor for either R F Power, AM, or FM. The CALIBRATE key also initiates tuned R F level Calibration operations. [See A M Calibralion, FM Calihrntion. RI: Power,
Titncd RF LAc~vcl.
30. CALIBRATION R F POWER OUTPUT makes available a 50 MHz, 1 mW power reference used to precisely determine the sensitivity of the external power sensor. [See RF Powc~.]
31. SET REF (Blue Key) enables the Measuring Receiver to accurately measure relative power changes; for example. in attenuator or amplifier measurements. [SeeA t/rnitator Mcawrc~mcws.]
32. POWER switch applies power to the Measuring Receiver when set to ON. [See In.i/ri/mcn/
Prcsct . ]
33. ZERO causes the Measuring Receiver to cancel any dc offset that may be present in the power sensor. [See RF Powtv-.]
34. PRE DISPLAY enables FM deviation to be measured before or after de-emphasis. [See FM
J
35. FM DE-EMPHASIS networks eqiialize pre-emphasized FM. [See FA4 I)c4hpha.~i.~.
36. HP (High-Pass) and LP (Low-Pass) FILTERS limit the demodulated signal bandwidth. [See
A iidio FiI/ur.\. J
37. LOCAL returns the Measuring Receiver to keyboard control from remote (HP-IB) control.
38. HP-IB Annunciators indicate remote operation status.
3-7
Operation Model 8902A
Model 8902A Operation
Rear-Panel Features
1. AM OUTPUT produces an ac signal, whose amplitude is proportional to the AM depth, with a dc component related to the IF level. The output is dc coupled with a 16 a 10 kit output impedance. [See AM Oirtpiri.] kHz bandwidth and
2. FM OUTPUT produces an ac signal, whose amplitude is proportional to the FM deviation, with a dc component related to the IF frequency. The output is dc coupled with a 16 kHz bandwidth and a 10 kR output impedance. [See FM Oictput.]
3. RECORDER OUTPUT allows user-access
Olrlpllf.
3
to all internal measurement voltages. [See Recorder
4. IF OUTPUT produces a 150 kHz to 2.5 MHz modulated IF signal. The output level ranges from -27 to -3 dBm (50R output impedance). [SeeZF Outpici.]
5. TIME BASE 10 external 10
MHz OUTPUT and INPUT. The input connector provides an input for an
MHz time base reference. The external input signal must be greater than 0.5V peak-to-peak (into a 500R input impedance). The output connector provides an output for the internal, high-stability 10 MHz reference. Output signal is TTL compatible (500 nominal output impedance). (Refer to paragraph 3-3. Timc Baw 10 MHz Inpiri and Timc Bajc 10 MHz Output.)
6. MODULATION OUTPUT/AUDIO INPUT is a rear-panel output and input supplied on
Option 00 I
Figure 3-1. instruments. Refer to MODULATION OUTPUT/AUDIO INPUT referenced from
7. SENSOR is a rear-panel input for the power sensor supplied on Option to SENSOR referenced from Figure 3-1.
001 instruments. Refer
8. INPUT is a rear-panel input for the RF input signal. This input is supplied on Option instruments. Refer to INPUT referenced from Figure 3-1.
001
9. Fuse. 2.5A (250V normal blow) for 100 or 120 Vac. 1.5A (250V normal blow) for 220 or 240
Vac.
10. Serial Number Plate. The first four numbers and letter comprise the prefix that denotes the instrument configuration. The last five digits form the suffix that is unique to each instrument.
11. Line Power Module permits operation from the window indicates the nominal line voltage to which the instrument must be connected.
Line Volrage and Firse
100,
Sdccrion)
120, 220, or 240 Vac. The number visible in
The center conductor is safety earth ground.
12. FREQ OFFSET TTL OUT outputs a voltage that can be and out of the path between a microwave input signal and the Measuring Receiver when the instrument is in Frequency Offset Mode. The TTL output is always OV if Frequency Offset
Mode is not selected or while Frequency Offset Mode is selected with an entered external LO value of output is +5V. If the entered external LO frequency is greater than 18 GHz, the TTL output is
3V. [See I;i-c.clirency used to switch an external mixer in
0 Hz. If the entered external LO frequency is less than or equal to 18 GHz, the TTL
Ol/w/ Conlrol. ]
13. HP-IB Connector connects the Measuring Receiver to the Hewlett-Packard Interface light as appropriate (REMOTE, LISTEN, TALK, SRQ).
BUS remote operations. When the HP-IB is being used, the annunciators next to the LOCAL key
14. REMOTE CONTROL can switch between the
R F Swifch. ]
RF SWlTCHES enable the user to build an internal sensor module that
RF INPUT connector and the SENSOR connector. [See RiwoIc Conrrol
15. LO OUTPUT and INPUT (Option 003 and Option Series 030 only). Option 003 provides an
LO output connector and an LO input connector. The LO output connector is provided to output the Local Oscillator signal. The output signal is 1.27 to 1301.5 MHz at approximately
0 dBrn
(Son)
nominal output impedance. The LO input connector provides an input for an external Local Oscillator. External input signal required is 1.27 to 1301.5 MHz at approximately
3-9
Operation Model 8902A
0 dBm (50n) nominal input impedance (LO Input and LO Output). Two jumpers are provided to allow the internal LO signal to be routed to the LO input connector when no external LO is in use.
The Option Series 030 instruments are provided with an LO input connector, an LO output connector and a remotely controllable switch which selects between them. If an external LO is connected but the signal is not in use, the switch routes the external LO signal back out the
LO output connector. [See High St>lwriviry .]
Do not apply rcwrsc powcr inlo Ihc LO OUTPUT or dumugc lo the instrrimcwl m a y rtwrII. the LO
Do
INPUT no( apply grcart’r lhan 40 Vdc or or damn@ to rhc
+5 dllm insrriimenf may rtwrlt. oj‘RF powcr info
16. CALIBRATION OUTPUT RF PWR and AMjFM prodiices a rear-panel output for RF Power and AM and FM calibrators. This oiitpitt is supplied on Option 001 instruments instead of the standard front-panel connection. Refer to both CALIBRATION R F POWER OUTPUT and
CALIBRATION AM/FM OUTPUT referenced from Figure 3-1.
3-10
HP
8902A
Measuring Receiver
Basic Operation and Application Guide
HP
8902A
Operation Made Easy!
HEWLETT
PACKARD
Table of Contents
1. Learning to Operate the HP 8902A
Chapter
1 provides an easy step-by-step guide to learning each of the HP 8902As basic measurement capabilities.
2. More about RF Frequency and
Frequency Error Measurements
Chapter
2 describes the HP 8902As special capabilites that enable you to adapt the RF Frequency and Frequency Error measurements to the special conditions of your application.
3. More about Modulation and
Audio Measurements
Chapter
3 describes the HP 8902As special capabilites that enable you to adapt the Modulation and Audio measurements to the special conditions of your application.
4. More about RF Level and Tuned
RF Level Measurements
Chapter
4 describes the HP 8902As special capabilites that enable you to adapt the RF Power and Tuned RF Level measurements to the special conditions of your application.
5. Measurement Examples
Chapter 5
contains specific measurement examples that demonstrate how the versatility of the HP 8902A enables you to use it in a wide range of measurement applications.
Appendix A
Appendix B
Appendix C
Appendix D
-
-
-
Installation
-
Calibration Factors
Index
Other Publications
Learning to Operate the HP 8902A
The Easy Way
This Basic Operation and Application Guide is designed to provide a quick and easy way to learn to operate the HP 8902A Measuring
Receiver. Chapter
(2
2 through will
4) provide you with all the information to use the HP 8902As basic measurement capabilities:
Modulation, Audio, RF Power, and RF
RF you need
Frequency,
Level. The subsequent reference chapters are devoted to the special functions and features that enable you to extend the operation of the HP 8902A. We strongly recommend that you first familiarize yourself with Chapter 1 before referring to the reference chapters. Once you are comfortable with the basic operation of the instrument, it will be easier for you to understand and implement the many additional features that the HP 8902A has to offer.
The HP 8902A Solution
The hands-on approach in this chapter demonstrates the extreme versatility of the HP 8902A. Placing the HP 8902A on your bench actually puts the capabilities of several instruments at your fingertips.
Many of the measurement capabilities of the following products are included in the HP 8902A.
0
0
0
0
0
RF Frequency Counter, to 1 Hz resolution
Modulation Analyzer, AM, FM, and @M ................
(1-5)
(1-9)
Audio Analyzer, frequency, distortion, and level ........ (1-15)
RF Power Meter, as accurate as the best
................
(1-18)
RF Level Meter, unprecedented accuracy to -127 dBm
.
(1-21)
The HP 8902A combines many of the capabilities required for calibration, troubleshooting, and design into a single instrument. In addition, the
HP 8902As many special function capabilities enable you to adapt its measurements to the demands of a wide range of test conditions.
1-2
The Setup
Diagram 1-1. Setup for Learning Basic Operation
To get ready to learn to use the HP 8902A, connect the HP 8902A, an
HP 11 722A Sensor Module, and a signal generator together as shown
The HP 8902A
If you are unpacking a new HP 8902A you will want to refer to the installation suggestions provided in Appendix A.
The HP 7 7 722A
The procedures in this guide are written for use with an HP 11 722A
Sensor Module. There are many power sensors that can be used with the HP 8902A as well. If you are using a power sensor
(rather than a Sensor Module), refer to your HP 8902A Operation and Calibration Manual for information on which power sensors can be used and how to operate them with the HP 8902A.
The Calibration Data
Once the HP 8902A is up and running, you will need to first determine if the calibration data for the Sensor Module you are using has been stored in the HP 8902A. Appendix B contains a procedure for determining whether the correct calibration data has been entered into the HI' 8902A.
(Refer to Appendix B if you are not certain that the calibration data for the Sensor Module you are using has been entered into the HP 8902A.)
1-3
The Signal Generator
The procedures in this guide are best performed using a signal generator that generates a single, stable steps from at least also have AM, FM
100 MHz
RF to signal that is tunable in 1
200 and (if available)
MHz.
@M
MHz
The signal generator should capability at a 1 kHz rate.
And You
Note
If you are now sitting comfortably in front of your HP 8902A, you are ready to begin. Start on the next page and follow the step-by-step guide to learning to operate the HP 8902A. You will soon discover how the
HP 8902A can increase both the ease and speed of many of your measurements.
If you plan to selectively refer to portions of Chapter 1, rather than perform all of the procedures in sequence, we recommend that you complete the procedures in the Frequency Counter portion
of
this chapter first. The Frequency Counter portion contains an introduction to the tuning and reset capabilities that are important to all of the
HP
8902A's measurements.
1-4
1. Take a look at the HP 8902A's Front Panel. Notice that label brackets have been placed over each key group to help you quickly find the function desired.
2. Note the gold and blue keys. These keys will enable you to select the
"shifted functions. As this guide will demonstrate, the shifted functions are selected by pressing the
gold
or blue key and then the desired function key.
3. Switch the HP 8902A from STBY to ON. Notice that as the HP 8902A powers up, it performs a self-test that includes turning on all front panel lights.
The Display
I r
I
- -
I
1
Input signal not sensed
~~
HP 8902A setting up measurement
1
I
J
The HP 8902A keeps you informed of its operating status by the dashes and error codes it places in its display.
Interpreting the Dashes
4. Adjust your signal generator to -40 dBm. This causes the HP 8902A to place two dashes in its display. Two dashes indicate that the level of the input signal is too low for the instrument to detect in its current measurement mode.
5. Set the signal generator to 0.0 dBm. Once the HP 8902A detects an input signal, it removes the two dashes from its display. Sometimes you will see the HP 8902A input signal. (The HP replace the two dashes with four dashes. Four dashes indicate that the instrument is involved in internally setting up the measurement. If the HP 8902A seconds, the instrument may be having difficulty tuning to an unstable
8902As displays four dashes for more than a few
Track Mode tuning, described later in this chapter, is typically a good choice for tuning to unstable signals.)
6.
Interpreting Error Codes
Press the CALIBRATE key. (See the adjacent instrument diagram for the key location.) The HP have attempted to select an operating condition that is not compatible with the measurement you are making. Error codes like this will keep you informed of both operator errors and input signal problems. The reference chapters (2,
8902A
3, and will display Error
4)
21 to inform you that you list the error codes that can be encountered for each measurement along with recommended recovery actions.
Frequency Counter 1-5
When your signal source testing requires an accurate RF frequency counter, the HP 8902A is a convenient solution. The HP 8902A makes it easy to tune to and measure the frequency of complex modulated signals.
If you haven't setup your HP 8902A, Sensor Module, and signal generator as
shown in Diagram 1-1 (page 1-2)
you will need to do the following procedures. so in order to perform
Adjust Your Signal Generator
RF Frequency
Frequency Increment
Amplitude
Modulation
....................
.......................
......................
100
.1 MHz
0.0
Off
MHz dBm
Measuring
1.
RF Frequency
Press the FREQ key and the green AUTOMATIC OPERATION key on the HP 8902A. That's all it takes to configure the HP 8902A as an RF counter. Notice that the HP 8902A automatically tunes to and displays the frequency of the input signal (approximately 100 MHz; the absolute value depends on the accuracy of your signal generator and the accuracy of the HP 8902A's time base reference.) Note also that
AUTO TUNING (the green LED on the front panel) is on. This LED lets you know that the instrument is in its automatic tuning mode.
1
Hz Resolution
2. To
7.4 increase the HP
SPCL *
8902A's display resolution to by pressing the digit keys 7
0
1
4 and the
Hz, key in
SPCL key (see the adjacent instrument diagram for key locations). If you enter a wrong digit, simply press the CLEAR key and begin again. Note that the SPCL key remains lit to show that a special function has been manually set.
I If the HP 8902A displays Error 23 when you enter 7.4 to provide 1 Hz counter resolution. Enter 7.1 display resolution.
SPCL, it is not equipped
SPCL instead to select 10 Hz
7-6 Frequency Counter
Measurement Ranges
That's all it takes to make an accurate frequency count on a stable signal throughout the following ranges:
I
150 kHz to 650 MHz
I
+30 to -25 dBm
650 MHz to 1300 MHz +30 to -20 UBm
Choosing a
Proper tuning is the key to making successful RF Frequency as well as other tuned measurements with the HP 8902A. The optimum tuning mode for your measurement will depend on the characteristics of the input signal.
3. Adjust your signal generator to 110 MHz. The HP 8902A should automatically tune to the new input signal. (Note that four dashes are placed in the display while the HP 8902A is tuning to the input signal.)
Manual Tuning Mode
4. Key 110
110
M H z
MHz. into the
HI'
8902A by pressing the digit keys 1 1 0 and the MHz key. Note that AUTO TUNING (the green LED) is now off. By keying in an RF frequency and pressing the MHz key, you have selected the instrument's Manual Tuning mode. The HP 8902As tuning is now set at
The Manual Tuning mode can also be selected by pressing the MHz key by itself. When you press the MHz key without keying in a frequency value, the HP 8902As tuning is set at the frequency currently being displayed.
5. Adjust your signal generator to 112 MHZ. The HP 8902A will display an Error 01 to let you know that the input signal is no longer within the tuning range set to. of the frequency (1 10 MHz) that the instrument was manually
Auto Tuning Mode
6. Press the key. is
You
Blue Shift key and the AUTO TUNING (TRACK MODE)
(Notice that the AUTO TUNING, green LED is on again.) The
HP
8902A now tuned to the frequency of the input signal. (The Auto Tuning mode is the right choice when measuring a single, stable input signal.)
Track Mode
7. Press the TRACK input signal.
MODE key. In Track Mode, the HP 890211 is locked to the
Frequency Counter 1-7
8. Increment your signal generator from 112 MHz to 100 MHz steps. The
HP
8902A in 1 MHz is now able to track the input signal as it changes frequency. (Track Mode is the right Choice when you are measuring a drifting or noisy signal.)
Remember
The HP 8902A makes checking RF frequency error a simple two-step process. Adjust your signal generator to 100 MHz.
1. Key 100 MHz into the
HP
8902A to manually tune it to the frequency of your signal generator (100 MHz).
2. Press the gold
(both keys should remain lit). The HP 8902A is now displaying the frequency difference (in kHz) between the manually tuned frequency (100
S key, and then the FREQ ERROR (FREQ) key
MHz) and the actual output frequency of your signal generator. (Note that the instrument displays a negative difference when the input frequency is less than the HP 8902As manual setting and a positive difference when the input frequency is greater.)
~ ~~
Manual tuning is always the right choice when measuring Frequency
Error because it establishes a knaon frequency reference. Also, the
Frequency Error measurement should only be made on a stable in pu t signa 1.
That’s all it takes to make Frequency Error measurements with the HP 8902A.
10 Hz Resolution
3. To display 10 Hz counter resolution, enter 7.1 SPCL by pressing the digit keys 7
0
1 and the SPCL key. Note that the key remains lit to indicate that a special function has been invoked.
7-8 Frequency Counter
Reset
The HP 8902A provides you with two ways to return its operating functions to their automatic operating condition. The following procedures demonstrate the two reset functions.
Automatic Operation
4. Press the instrument back in its Auto Tuning mode (green you have disabled Special Function 7.1 (SPCL key no longer lit).
1 the green AUTOMATIC OPERATION
Pressing the AUTOMATIC OPERATION key key. You have placed on) and through 10 to their Automatic Operation condition and returns the instrument to its Auto Tuning resets Special Functions mode (not the best choice for
Frequency Error measurements, remember). Note that the instrument is still in the Frequency Error measurement mode (gold S key lit).
instrument Preset
5. Now press the Blue Shift key and then the green INSTR PRESET
(AUTOMATIC OPERATION) key. Note that the instrument is reset to the Frequency measurement mode (gold S key off). INSTR PRESET resets the entire instrument to its power-up default condition.
1. Selects Auto Tuning
2. Resets special
1 through 10
Automatic to functions their
Operation can cause an error
TO Learn More...
Chapter 2
RF Frequency and Frequency Error measurements and the more about:
HP 8902As tuning capabilities. Refer to Chapter 2 when you want to find out
0
-
Further information about the HP 8902A's
0
Tuning Modes tuning modes.
Extending Operation
- enable you to adapt the
The speaal operating capabilities that
Frequency and Frequency Error measurements to the specific conditions of your input signal.
0
Help - Solutions to setup or operating problems encountered when making RF Frequency or Frequency Error measurements.
Refer to Chapter 5 for examples of RF Frequency measurement applications.
Modulation Analyzer 7 -9
The HP 8902A offers complete modulation analyzer capability to meet your AM, FM and +M measurement needs. Even difficult measurements such as signal-to-noise and incidental AM and FM can be made with ease and superb accuracy using the HP 8902A.
Set up your HP 8902A, Sensor Module, and signal generator as shown
Adjust Your Signal Generator
RF Frequency
Amplitude
Modulation
Depth
Rate
....................
.......................
......................
...........................
.............................
100 MHz
0.0 dBm
AM
.50%
1 kHz
Measuring AM
1. Press the AM key, the green AUTOMATIC OPERATION key, and the
PEAK+ detector-key. The instrument should display an AM index of approximately 50%. Notice that the instrument is in the Auto Tuning mode (green AUTO TUNING LED on). The HP 8902A automatically found and tuned to the modulated RF signal. (The Auto Tuning mode is a good choice for making most modulation and audio measurements.)
. . . . . . . . . . . . . . . . 2. Key in 100 MHz by pressing the digit keys 1 0 0 and the MHz key. The instrument is now manually tuned to the frequency of the input signal (green LED off). (Manual Tuning is a good choice when measuring modulation in the presence of multiple RF input signals.)
1-70 Modulation Analyzer
Selecting a Defector
The HP 8902A provides six detector functions for measuring your modulation and audio signals.
Peak Detector
3. Press allows the PEAK- key. Switching between the Peak+ and Peak- detector you to check modulation symmetry.
4. Press both the PEAK+ and PEAK- keys at the same time. Pressing both detector keys at the same time allows you to display the average value of the positive and negative peak readings. (PEAK f/2).
5. Press the PEAK+ key and then the PEAK HOLD key. The Peak Hold detector captures and holds the peak modulation level detected by the
Peak+ or Peak- detector.
6. Increase the modulation depth of the signal generator to 75% and then reduce it back to 50%. Notice that the HP 8902A continues to display the maximum modulation level. The Peak
Hold detector is ideal for detecting short modulation transients.
7.
Average Detector
Now press the AVG key to select the average-responding detector.
You have selected an average responding detector that is calibrated to read the rms value of a sinewave. The HP 8902A should be displaying approximately 35% AM with the signal generator set at 50% AM.
8.
RMS Detector
Press the Blue Shift below the RMS key key will and then the RMS
You
(AVG) key (the red LED have now selected a true-RMS detector. The Average detector and the RMS detector are good choices when measuring noise or residual modulation where the generally more desirable than the peak value. The true-RMS detector can be used to measure modulation rates up to 40 nns value is kHz and provides one more digit of resolution than the Average Detector. The true-RMS detector is also a good choice for measuring non-sinusoidal signals.
Simply select AM and any of the above detector functions to make AM measurements within the following ranges:
RF Carrier Frequency Modulation Rate Max. Depth
150 kHz to 9.999999
10 MHz to 1300 MHz
20 Hz to 10 kHz
20 Hz to 100 kHz
99%
Modulation Analyzer 7-7 7
Measuring FM
1. Turn off AM on the signal generator and turn on 25 kHz of FM deviation at a 1 kHz rate.
2. Press the FM key, the green AUTOMATIC OPERATION key, and the
PEAK+ detector key. The HP 8902A should display a reading of about
25 kHz. Notice that in the upper right comer of the instrument the yellow FM MODULATION OUTPUT LED is lit. This indicates that the demodulated FM signal is available at the front-panel MODULATION
OUTPUT/AUDIO INPUT port. (Connecting another audio analyzer to this port will enable you to make audio measurements on the demodulated signal while monitoring modulation with the HI' 8902A.)
To accomodate your pre-emphasized FM signals, the HP 8902A is equipped with four separate de-emphasis filters. (Each FM DE-EMPHASIS key is labeled with a time constant corresponding to the 3 dB comer frequency of that de-emphasis filter.)
3. Press the 75ps FM DE-EMPHASIS key (if the PRE-DISPLAY key is not lit, press it too). The display now shows the level of the demodulated signal after it has been de-emphasized. (The de-emphasized FM signal is now available at the front-panel MODULATION OUTPUT/AUDIO INPUT port.)
4. Press the PRE-DISPLAY key again to turn Pre-Display off.
Notice that the display now shows the level of the demodulated
FM signal before it is de-emphasized. The demodulated signal is now being applied to the de-emphasis filter after it is measured by the HP 8902A. (The de-emphasized signal is still present at the MODULATION OUTPUT/AUDIO INPUT port, however.)
5. Press the 75ps key again to turn off the FM De-emphasis function. Repeat step 3 to select any of the four de-emphasis filters.
Inserting Audio Filters
6.
To remove undesired signals such as harmonics, noise, and spurs from the demodulated signal, insert the selectable high-pass and low- pass audio filters when making modulation or audio measurements.
To minimize overshoot from square-wave modulation, such as frequency shift keying (FSK),
Press the 300 Hz key and the 3 kHz key to set a typical measurement bandwidth of 300 Hz to 3
kHz. Diagram 1-2 shows the typical frequency
response of each audio filter.
1-12 Modulation Analyzer
7. Press the 300 Hz key these filters. and the 3 kHz key again to remove lw)
Typical 50 Hz High-Pass Filter Response TypicSl300 H t High-Pass Filter Rwmse
L
90
I
5 8 0
80
f
$ 8 0 v.
40
0
70
0 1w iM
MOMJUTION RATE (Hi)
200
100
Typical3 kHt LOW-PaJS Filter Response
2%
1 2 3
MOWLATION RATE BHi]
4 5
80 p
40
1OO
0
I
200
I f rw 6w
MoDULA7loN RATE (HY)
I
800
Typical 15 kHt Low-Pass Filter Response
1 lob3
1W
Typical >20 kHt Low-Pass Filter Response
4 8 12
M0WUTH)N RATE
(wr)
16
I
w
$ 8 0 u.
40
0 20 40 w e4 io0 120
MOMJLATlON RATE (KHz)
140 ?e4
Diagram 1-2. The typical frequency response of each Audio Filter
That’s all it takes to make FM measurements and select audio filters out the following ranges: through-
RF Carrier Frequency Modulation Rates W D e r i a t i O n
150 kHz to 9.99999 MHz 20 Hz to 10 kHz 40 kHz peak
10 MHz to 1300 MHz 20 Hz to 200 kHz 400 kHz peak
Modulation Analyzer 1-13
Measuring #M
1. Turn off the FM on the signal generator and select 10 radians phase modulation at the rate of 1 kHz. (If your signal generator does not have
@M capability, set modulation to FM, 10 kHz deviation at a 1 kHz rate.)
In Radians
2. Press the @M key, the green AUTOMATIC OPERATION key, and the PEAK+ detector key. The HP 8902A should display a reading of about
OUTPUT
10 radians. Notice that the yellow @M MODULATION
LED is now lit to indicate that the demodulated @M signal is available at the MODULATION OUTPUT/AUDIO INPUT port.
(An audio measurement device, such as an oscilloscope, can be connected to this port for monitoring the demodulated audio signal.)
In Degrees
3. Key in 1.745 and then press the RATIO key. The HP 8902A is now displaying the phase deviation in degrees. reading in dB, press the LOG/LIN key to get '7'0. The instrument should display approximately 570 degrees for
(If
10 the display is radians of 9M.)
qiM
Select the @M measurement mode to simplify your phase modulation measurements throughout the following ranges:
MODULATION RATE (HZ)
1-14 Modulation Analyzer
TO Learn More...
Chapter 3 in this guide provides additional information about the modulation measurements. Refer to Chapter 3 when you want to find out more about:
0
0
0
Calibration - The procedure to calibrate your
FM measurements.
AM and
Extending Operation your input signal.
-
The special operating capabilities that enable you to adapt the Modulation measurements to the specific conditions of
Help - Solutions to setup and operating problems encountered when making modulation measurements.
Refer to Chapter 5 for examples of modulation measurement applications.
Audio Analyzer 1-15
The HP 8902A enables you to measure your audio signal sources as well as your RF signal sources. Use the HP 8902A to make audio frequency, distortion, and level measurements.
Set up your HP 8902A, Sensor Module, and signal generator as shown
Adjust Your Signal Generator
RF Frequency
Amplitude
Modulation
Depth
Rate
....................
...........................
100 MHz
0.0 dBm
AM
.50%
1 kHz
Audio Frequency
The HP 8902A enables you to accurately count the frequency of the internally-demodulated audio signal or of an external audio signal connected to the MODULATION OUTPUT/ALJDIO INPUT port.
1. Press the AM key and then the green AUTOMATIC OPERATION key.
Entering the AM measurement mode first, selects the AM demodulator for measuring the AM input signal. The HP 8902A uses the last demodulator selected before entering an audio measurement mode to make its audio measurements. (Notice that the yellow AM MODULATION OUTPUT is lit. When you are making audio measurements, the MODULATION
OUTPUT LEDs will show you which demodulator is selected.)
LED
1-76 Audio AnaIyzer
2. Press the gold S key and then AUDIO FREQ (AM) key (both keys should remain lit). The HP 8902A is now displaying the frequency of the demodulated audio signal (approximately
1 kHz). The demodulated audio signal is also available at the front-panel MODULATION OUTPUT/AUDIO INPUT port.
External Audio
3. Press the AUDIO INPUT key (key lit) to convert the MODULATION
OUTPUT port to an AUDIO INPUT port. The HP 8902A is now able to make its audio measurements on an external audio signal source connected to the AUDIO INPUT port. Press the AUDIO INPUT key again to convert the port back to a modulation output and continue measuring the internally demodulated audio signal.
That's all it takes to measure internally-demodulated or external audio frequencies throughout the following ranges:
---
Use the HP 8902A to measure distortion on either a 400 Hz or a 1 kHz signal. Distortion measurements can be made on either the internally demodulated signal or on an external audio signal connected to the
AUDIO INPUT port.
1. Press the gold S key and the AUDIO DISTN (FM) key (both keys should remain lit). The instrument is now displaying the measured distortion of the 1 kHz demodulated signal. Notice that in the display, the 1 kHz annunciator is lit. The true-RMS detector is used to make this measurement.
2. Press the Blue Shift key and the 400 H t DISTN (PEAK-) key (the 400 annunciator should be lit in the display). The instrument is now ready to measure the distortion level of a 400 Hz signal.
Hz
Audio Distorfion
That's all it takes to measure audio distortion throughout the following measurement ranges:
400 Hz and 1 kHz 0.01% (-80.0 dB) to
(0.00 dB)
Audio Analyzer 1-17
Measuring
Audio
Level
1.
The H p audio signals is able to measure the
rms
INPUT signals.)
When you need to measure audio level, connect to the AUDIO INPUT port. an audio source
2.
3.
Key in 30.0 SPCL. The instrument will display the rms of the input signal. (Press the Blue Shift key and the voltage unit keys pV (4), mV (5), or Volts (6) to select the desired voltage
units.)
Press any measurement measurement mode. function key to exit €he Audio Level
That's all it takes to measure audio level throughout the following ranges: a
To
Learn More.
..
I I
Chapfer 3 in this guide provides additional information about the HP 8902A
Audio measurement capabilities. Refer to more about:
Chapter 3 when you want to know
0
0
Extending Operation - The special operating capabilities that enable you to adapt the Audio measurements to the specific conditions of your input signal.
Help -
Solutions to setup and operating problems encountered when making Audio measurements.
Refer to Chapter 5 for examples of Audio measurement applications.
1-18 RF Power Meter
The HP 8902A provides you with the capability and accuracy of the best power meters. With a single keystroke, the HP 8902A autoranges to the input signal, measures its power, compensates for power sensor flatness, and displays the results in the units of your choice.
Adjust Your Signal Generator
RF Frequency
Amplitude
Modulation
....................
......................
100
0.0
Off
MHz dBm
Power
Like all power meters, the HP 8902A must first be calibrated. An internal RF Power Calibrator enables you to calibrate the Sensor
Module and the HP 8902As Power Meter to an internal 50 MHz,
1.00 mW reference signal. The following calibration procedure must be performed only one time to calibrate your Sensor Module. This means you do not need to perform this procedure again as long as you are using the same Sensor Module. To ensure the highest possible measurement accuracy, allow the HP 8902A to warm up for at least thirty minutes before performing the calibration procedure.
1. Press the RF POWER key on your HP 8902A.
Error 15
If the HP 8902A is displaying Error 15, it has not yet been configured to make RF Power measurements. (Refer to Appendix
Calibration Factor Entry procedure before going
B and perform the on with this procedure.)
The calibration factors for the Sensor Module you are using must be stored in the HP 8902A in order for it
RF to make calibrated, automatic
Power measurements. If you are not certain that the correct calibration factors are stored in the instrument, refer to Appendix B.
RF Power Meter 1-19
Remember
2. Connect the
HP
11722A
OUTPUT port on the
Sensor Modale to the
HP
8902A. This
RF POWER port outputs the 1.00 mW reference signal. (Disregard Error 11 when it is displayed.)
3. Press the ZERO key. Wait approximately 8 seconds for the zeroed sensor reading to be displayed briefly. The Hp 8902A is correcting for any dc offset error inherent within the measurement system.
As a good rule of thumb, press the mery 10 minutes when making RF
ZERO key approximately
Power or Tuned if the ZERO key is pressed with the HP 11722A
RF
Sensor
Module connected to the signal source being measured.
Level measurements to compensate for any changes in the ambient operating conditions. The zeroing process is most effective
4.
5.
Press the CALIBRATE key. Wait for a stable, calibrated reference reading to be displayed. The
1.00 mW reference.
HP
8902A is creating a correction factor that enables the instrument to equate its power measurement reading to the
Press the Blue Shift key and then the SAVE CAL (CALIBRATE) key.
This stores the calibrated reference in the instruments non-volatile memory.
6. Press the CALIBRATE key again. This turns completed the calibration procedure. off the calibrator. You have
7. Connect the Sensor Module to the signal generator. The HP 8902A
Module you are using. From now on, you need only repeat step 2 to maintain RF Power calibration. is now calibrated to make accurate power measurements with the Sensor
Measuring
1. Press the RF POWER key. The instrument should read approximately
RF Power
2.
1000 -06W (1000 pW) with the signal generator set to 0.0 dBm.
Press the LOG/LIN key to toggle the display reading between logarithmic (dBm) and linear (watts) units. The instrument also converts measurement readings to voltage units when you select the Blue Shift key and a voltage units key such as
Shift key and then the WATTS pV
(9)
(4), mV (5), or V (6). Press the Blue key to exit the voltage units mode.
Changing Frequency
3. Adjust the frequency of the signal generator to 119 MHz.
Manual Tuning
HP
the new output frequency
8902A of the signal generator into the by pressing the digit keys 1 1 9 and then the MHz key. The HP 8902A must be set to the same fiequency as the input signal to enable the instrument to select the correct calibration factor.
7-20 RF Power Meter
5.
Auto Tuning
You can also allow the HP 8902A to automatically tune to the new input frequency, by pressing the FREQ key, the Blue Shift key, and the AUTO TUNING (TRACK MODE) key. After the HP 8902A displays the new input frequency, press the MHz key and then the RF POWER key to re-enter the RF Power measurement mode.
If the frequency of the input signal changes, always change the frequency setting of the HP 8902A as well.
6. To verify that the frequency setting of the HP 8902A is the same as the frequency of the signal and then the DlSP FREQ (kHr fr) key. You
Blue Shift key can use this method to check frequency tuning when in any of the measurement modes.
RF Power
Measurement Ranges
From now on, simply select RF Power to make accurate, calibrated measurements throughout the following ranges using an HP 11
Sensor Module:
RF Power
722A
To Learn More
...
Chapter 4 in this guide provides information about the HP 8902A's additional capabilities when in the you want to find out more about:
RF Power mode. Refer to Chapter 4 when
0
0
Calibration - The RF Power calibration technique.
Extending Operation you to adapt the RF your input signal.
- The special operating capabilities that enable
Power measurement to the specific conditions of
0
Help - Solutions to setup or operating problems when making
Power measurements.
RF
Refer to Chapter 5 for examples of RF Power measurement applications.
Rf Level Meter 1-21
The HP 8902A offers unprecedented low-level measurement capability.
Select the Tuned RF Level measurement to make precise, narrowband
RF level measurements down to -127 dBm. The Tuned RF Level measurement is an excellent choice for performing low-level accuracy tests.
Set up your HP 8902A, Sensor Module, and signal generator as shown in
Adjust Your Signal Generator
RF Frequency
Amplitude
Amplitude Increment
Modulation
....................
......................
119
Off
MHz
0.0 dBm
............ 10 dB
Tuned RF Level
To make accurate low-level measurements down to -127 dBm, the HP 8902A uses a precise, IF signal substitution technique. This technique creates three RF measurement ranges within the full measurement range of the tuned RF Level measurement (0 to -127 dBm).
Tuned RF Level calibration involves the creation of a calibration factor for each of the three ranges at the tuned frequency. The following simple procedure creates these calibration factors. (More information about the calibration technique is provided in Chapter 4.)
1. Press the FREQ on the
HP
key
8902A. and then the green
This tunes the HP 8902A to the input signal. When the
HP 8902A displays the input frequency, press the MHz key (to select Manual
Tuning), the gold S key, and then the TUNED RF LEVEL (RF POWER) key.
(Both the gold S key and the TUNED RF LEVEL key should remain lit.) You may see the HP 8902A place six
AUTOMATIC OPERATION key dashes in its display prior to displaying the measurement reading. The instrument displays six dashes only when in the TRFL measurement mode. Six dashes indicate that the HP 8902A is searching for an input signal at the frequency that it has been tuned to.
1-22 RF Level Meter
2. Press the that the
HP
generator (119 in 11 9 MHt.
8902A key and the
If it is
DISPLAY FREQ (kHz not, manually tune it
(Manual Tuning is the right choice for fi) is tuned to the output frequency of the signal
TRFL key to check measurements.)
3. Both the RECAL and the UNCAL annunciators should be lit in the display.The UNCAL annunciator indicates that the displayed reading is not yet calibrated. The RECAL annunciator indicates that calibration is
MHz,
(If the
HP 8902A has already been calibrated at 119 the annunciators will not be lit. You can enter 39.9 SPCL to clear the calibration factors for 119 MHz so that you can continue with
this
demonstration.)
4. Press the CALIBRATE key. After the instrument completes the calibration process, both annunciators will go out. You have just calibrated Range 1
(0 to -40 dBm). (No further calibration is required to accurately measure input levels within this range.)
Note
I t is very important that the level of the input signal remain stable during the calibration process (while the CALIBRATE key is lit).
5. Press the LOG/LIN
(dBm) units. key to select either linear (Watts) or logarithmic
6. Decrement the signal generator level in 10 dB steps down to
-40 dBm. Note that neither the RECAL or UNCAL annunciator is lit until you get to -40 dBm. This means that each of the displayed readings down to -40 dBm is a fully calibrated measurement.
7. At -40 dBm, the instrument displays the RECAL annunciator again. The RECAL annunciator indicates that the HP 8902A needs to be recalibrated now in order to make accurate level measurements within its next RF measurement range (approximately -40 to -80 dBm).
Note that the UNCAL annunciator is not displayed. This means that the displayed reading is still a fully calibrated measurement.
Range 2
8. Press the CALIBRATE key. After the instrument completes the calibration, the RECAL annunciator will
Range 2 (-40 to -80 dBm). go out. You
TRFL have now calibrated
9. Continue decrementing the signal generator to
RECAL annunciator will be displayed again.
-80 dBm. The
Range 3
10. Press the CALIBRATE key again to calibrate Range 3. The instrument is now calibrated to make level measurements (at
119 MHz) over its entire measurement range (0 to -127 dBm).
You can now adjust the output level of the signal generator to any level between 0 and -127 dBm and no further calibration will be needed to measure the 119 MHz signal.
RF Level Meter 1-23
Measuring
The following information is provided to help you q u i d y complete your
Tuned RF Level measurements.
Changing
Frequency
Achieving the accuracy of the Tuned RF Level
(TRFL)
requires that the calibration procedure be repeated at each frequency to be measured. The following chart will help you remember the key steps to performing TRFL measurements.
..*.........
RECAL UNCAL
is uncalibrated. The HP 8902A displays the UNCAL change in the frequency or level of the input to use an RF measurement range that is signal annunaator when a requires the instrument not yet calibrated. The RECAL a m c i a t o r is displayed when the input signal is at a level where it can be used to calibrate the next (uncalibrated), RF measurement range. The following chart will help you to quickly interpret these annunciators.
ON ON next measurement range is possible.
The displayed measurement is the next RF measurement range.
Press the CALIBRATE key to calibrate the
RF measurement range you are in.
1-24 RF Level Meter
That's all it takes throughout the following frequency and level ranges using an
Sensor Module: to make accurate Tuned RF Level measurements
HP 11722A
To
Learn More...
Chapter 4 in this guide provides additional information about the TRFL measurement and the extended capabilities that will help you adapt the measurement to your needs. Refer to more about:
Chapter 4 when you want to find out
0
Calibration - Understanding the TRFL calibration technique.
0
0
Extending Operation - The special operating capabilities that enable you to adapt the TRFL measurement to the specific conditions of your input signal.
Help -
Solutions to setup and operating problems encountered when making TRFL measurements.
Refer to Chapter applications.
5 for examples of Tuned RF Level measurement
Special Function Operation 1-25
To
-mbm extend instrument
Most measurements made with the to
HP
8902As
HP 8902As
HF'
8902A require only a keystroke invoke. There is no need to adjust levels, or select ranges because the
The microprocessoF determines the optimum instrument settings automatically. However, in some applications it is desirable to override the automatic selection. Speciai functions provide you with manual control of instrument operation, selection special functions are described in the of additional measurement modes, and the ability to extend measurement ranges. following chart. codes
1
to
10 These special functions enable you to select and adiust specific
The SpeCjd Display
Special function modes are selected first by entering the appropriate code
(prefix, decimal point, suffix) and then pressing the SPCL key (lower right comer on the front panel).
1. Key in 7.2 SPCL. The SPCL function has been invoked. key remains lit to indicate that a special
1-26 Special krnction Operation
2. Now press the SPCL key alone. Pressing the SPCL key without entering a number causes the HP have been set. If
8902A to display which special functions you previously entered the 7.2 special function, a
(1-10)
2 should now appear in the seventh display digit position. The display shows a zero in each of the other display positions to indicate that these special functions are still set to their automatic (default) operating condition. Use this capa- bility to review or verify the special function settings that you have selected.
3. Press the SPCL key again. Pressing the SPCL key twice without entering a number causes the instrument to display the special function setting (1-10) currently in. actually being used. (Note that a 2 still appears in the seventh display digit position.) The other digits represent the settings automatically selected for the measurement mode the
Use
HP this capability when you are interested
8902A in is knowing what settings the instrument is currently using to make its measurements.
4. Press the CLEAR key to exit the special function display and return to the previously selected measurement mode.
FUnCfiOn
The Speck/
PU//-OUf
Card
The Special Function Information pull-out card enables an experienced user to quickly access special function operating information. diagram on the card shows which portions of the circuitry are controlled by special functions special function functions 11-39
1-10.
(1-10)
A table of operating conditions for each is provided below the block diagram. Special are listed above the block diagram along with a brief description of their function. (Refer to the measurement reference chapters (2 through 4) and the applications chapter special functions can help you
(5)
A block to find out how expand your measurement capabilities.)
Errors, Dashes and Other Help
The HP status by placing error and dash codes in its display. The Operating
Information pull-out card enables of each code. The measurement reference chapters chapters
8902A you to quickly access a brief description
(2 through 4) in this guide provide a listing of the errors and problem conditions for each of the measurement modes. Each code listing includes a description and recommended recovery action. (Refer to reference
(2
Measuring Receiver keeps you informed of its operating through 4) for help in solving your measurement problems.)
Congratu/ations
You are now familiar with each of the basic measurement capabilities of the HP 8902A. From now on, you can rely on the HP 8902A for making your frequency, modulation, audio, power, and level measurements.
The rest of this guide will enable you to expand and extend the
HP 8902A's the HP measurement capabilities even further. your applications goes beyond the contents of this guide, refer to
8902A
If the scope of
Operating and Calibration Manual for further details.
/n This Chapter
This chapter introduces the HP 8902A's special operating capabilities that enable you to tailor its RF measurements to your specific test conditions. capabilities effectively, you should first become familiar with the basic operating capabilities and measurement ranges described in
Chapter
I
for the RF
Frequency and Frequency Error
(To use these special
Frequency and Frequency Error measurements.)
This chapter enables you to reference directly to the information you are interested in. The information is organized into three subject areas.
0
0
0
Tuning Modes
-
Refer here for tuning modes.
Extending Operation - further understanding of the
Refer here for the special operating capabilities that enable you to adapt the conditions of your input signal.
HP
8902A to the specific
Help - Refer here for help encountered in in solving setup or operating problems
RF Frequency or Frequency Error measurements.
The Directory
Use the directory diagram below to quickly locate the subject you are interested in. A look-up table is located on the first page of each subject area. Use the look-up table to reference to the topics included for that subject.
2-2 Tuning Modes
Tuning Modes
If
Y m
Need
to
K n m
e
How
the Auto
0
How
the
Refer
to:
Auto
Tuning
Auto tuning allows the HP 8902A to automatically find and tune to the input signal. It is automatically selected on Power-Up, or when the
AUTOMATIC OPERATION or INSTR PRESET key is pressed. Auto Tuning mode is also selected by pressing the Blue Shift key and then the AUTO
TUNING key.
When the HP 8902A enters the Auto Tuning mode, it first checks for an input signal below instrument then begins sweeping down to 2.5 MHz. created by the
2.5
The mixing
MHz.
LO
If no signal is detected below its local oscillator continues sweeping
LO and the RF until
(LO) a
2.5
1300 different frequency, the IF passband. If no signal is detected after multiple sweeps, the the
MHz input signal, appears within instrument places two dashes in its display while it continues to sweep.
When a signal does appear within the IF passband, the instrument performs a series of tests to determine whether the signal it has found is the appropriate signal to tune to.
Tune to the fundamental in harmonically-rich spectrums or to a carrier with high-depth AM.
This testing enables the HP 8902A to Auto the correct frequency, the HP 8902As LO is locked to an internal crystal oscillator to ensure high-stability, low-noise measurements. If the input signal changes after the LO has been locked to the crystal oscillator in Auto
Tuning mode, the LO
Once the instrument determines that it is tuned to automatically begins the sweep search again. Auto
Tuning mode is a good choice when measuring a single, stable input signal.
Keep in mind that certain input signal conditions can make it difficult for the HP 8902A to Auto Tune. The Manual Tuning mode is a good choice when these conditions exist. For a refer to
Input Conditions that listing of these conditions,
may
Require Manual Tuning.
Tuning Modes 2-3
Table 2-1. Input Conditions That May Require Manual Tuning.
If the desired signal is the desired frequency. a low pass filter at frequency or rem auto tuned to the signal.
I
* dBc = decibels referenced to the carrier level.
Dr it may alternately display hes then four dashes
Manually tune to the carrier frequency to increase measurement sensitivity. (Refer to
Incmashg Sensitivity in this chapter to extend the measurement range further.)
2 4 Tuning Modes
Manual Tuning
The Manual Tuning mode allows you to set the HP 8902A’s tuning at a desired frequency. This is done by keying in the desired frequency and then pressing the MHz key. The manual tuning mode can also be entered by pressing the MHz key by itself. This locks the instrument at the frequency it is currently tuned to.
In Manual Tuning mode, the HP 8902A‘s local oscillator (LO) is locked to the HP 8902A‘s internal crystal oscillator whether an input signal is present or not. Once the LO is locked to the crystal oscillator in Manual
Tuning mode, tuning does not change unless a new frequency is keyed in and the MHz key is pressed, or tuning is incremented up or down using one of the increment keys, tkHr or VkHz. (Set an increment by keying in the desired increment value and pressing one of the increment keys. The instrument will increment by the keyed-in value each time one of the increment keys is pressed.) Press the AUTO TUNING key or the AUTOMATIC OPERATION key to exit the Manual Tuning mode.
Manual Tuning is a good choice when measuring an input signal whose amplitude is less than -25 dBm or unstable, or where multiple RF signals are present. If the input signal is drifty, however, it may be necessary to select the Track Mode function.
Track
Mode
The Track Mode function enables the HP, 8902A to track drifting input signals from 10 MHz to 1300 MHz. Track mode can be selected with either
Auto Tuning or Manual Tuning by pressing the TRACK MODE key. (A drifting signal will cause the HP 8902A to place four dashes in its display when Auto Tuning is selected or Error 01 when the instrument is manually tuned.)
In Track Mode the Local Oscillator (LO) is locked to the input signal.
The instrument remains locked to the signal throughout each of the
LO’S tuning octaves. When an input frequency change causes the LO to cross into a new octave, lock may be broken. If the instrument is in Auto Tuning Track Mode, the HP 8902A will relock to the input signal. If the instrument is in Manual Tuning Track Mode, the LO will return to the manually tuned setting after lock is broken. The octave boundaries occur at 2.5, 5, 10, 20, 40, 80, 160, 320, 640, and 1280 MHz.
Track Mode is the right choice when measuring drifty input signals.
However, certain operating limitations are present when using Track Mode.
These limitations are listed below:
0
Not allowed below 10 MHz
0
Not allowed with 455 kHz IF
0
Raises residual FM level
0
Attenuates low-rate FM on input signal (use for FM rates >1 kHz only)
Extending Operation 2-5
Increasing Se/ectiv
rv
The HP 8902As Auto Tuning mode is able to automatically find and tune to the fundamental in a harmonically-rid is at least 10 dB above the level
HP 8902A will also not meet these criteria, the desired input signal.
Hp desired input signal, manually tune the spedrum
8902A may have as long as the fundamental the second and third harmonics. The auto tune to the input signal all non-harmonically-related
If
RF signals. If, if it is at least difficulty
30 dB above however, your input signal does auto tuning to the the instrument does not display the frequency of the
HP
8902A to the input frequency by keying in the frequency of the input signal and then pressing the MHz key.
To minimize the possibility of unwanted low-frequency, harmonic, or spurious signals entering the IF passband, a high-pass RF filter and bandpass IF
filters can be selected. Table 2-2
shows the possible filter
2-6 Extending Operation
Table 2-2. Filter Configurations
RF H i g h - h s s
Fitter
15-25
rn
OUT
W&
IF fUter
Narrow IF
(30
F i b kHz Bw)
Automatic Selection
Kw
3.0 SPCL
Changing
frequency
Although the input signal.
HP for the input signal after the frequency of the input signal is changed. The instrument will place four dashes in its display while it is searching for the lmage Signals
8902A is not designed for swept measurement applications, its Auto Tuning mode does enable it to automatically search
If the frequency of the signal is increased by an increment equal to twice the IF signal frequency (for example, 2 frequency will appear within the of the input signal is too fast, the
IF x passband.
HP
If
8902A will
MHz), the image the switching speed not detect a change in the input frequency and will continue to erroneously display the previous frequency.
Shift key and then the AUTO TUNING key after the input frequency has changed. This
If you suspect that this has happened, press the causes the HP
Blue
8902A to retune to the input signal.
IF
30 kHz filter can reduce the possibility of image signals appearing in the passband (refer to increasing Selectivity in this chapter for filter selection information). (For details on the capabilities and limitations of Auto Tuning mode operation, refer to Auto Tuning in this chapter.)
Noisy
Signal
Excessive noise or low-rate (below 20
400 the carrier signal can make to auto tune to the carrier. the kHz)
HP on
If you
Hz), know that it difficult for the HP 8902A your input signal is noisy, or if by continuously displaying four dashes, manually tune the HI’ 8902A to the frequency of the input signal. Simply key in the frequency of the input signal and then press the MHz key. If the HP 8902A does not display a measurement reading, press the TRACK MODE key.
Extending Operation 2-7
Drifty Signal
A drifty or noisy input signal can cause the instrument to continuously display four dashes (Auto Tuning mode) or display Error 01 (Manual Tuning mode). Press the TRACK MODE key to select the wide-IF-bandwidth track mode function. Track Mode can be selected with either the Auto or Manual tuning modes. Note that the Track Mode function reduces the low frequency response of modulation measurements and increases the level of residual modulation. (For details on the capabilities and limitations of Track Mode operation, refer to Track Mode in this chapter.)
Frequency Overrange
There are three techniques for extending the HP 8902A's frequency range above 1300 MHz: internal harmonic mixing, external local oscillator and mixer down-conversion, and down-conversion with a spectrum analyzer. All three techniques extend the measurement capabilities of the HP 8902A to microwave frequencies. (Refer to
Chapter 5 for measurement examples using these tuning techniques.)
Frequency Underrange
If the input frequency is below the HI? 8902As frequency measurement range, the instrument will display Error 10. The specified low frequency limit of the RF Frequency measurement is 150 kHz. However, you can extend this measurement range to 20 Hz by simply selecting the
Audio Counter. Connect your signal source to the MODULATION
OUTPUT/AUDIO INPUT port and press the AUDIO INPUT key (key should remain lit). Press the gold S key and the AUDIO FREQ key. The
Audio Counter will accurately count input signals from 20 Hz to 250 kHz.
Increasing Sensitivity
Two dashes or 0 MHz in the display indicates that the level of the input signal is below the HP 8902As present measurement range. However, the
HP 8902A's special function capabilities enable you to make RF Frequency and Frequency Error measurements on input signals down to -100 dBm.
The special function codes and their respective ranges are shown in
Diagram 2-1. Keep in mind that these special functions add gain in the
RF and IF paths. If the input signal level exceeds the designated range for
the special function you select (as shown in Diagram 2-1)
the instrument may overrange and display Error 02. Therefore, if you do not know the output level of your source, simply sequence down through the special function range settings until Error 02 is replaced by a measurement reading.
2-8 Extending Operation
+20
-
E?
0
-20
5
-40
I-
z
-60
-80
-1 00
25 40 100
INPUT FREQUENCY (MHz)
Diagram 2-1. Typical Frequency Measurement Ranges lo00 1300
Unstable Signal
If you are measuring an input signal whose RF level does not remain above -20 dBm to -25 dBm, (for example, a low level signal with high-depth AM or a signal that is being pulsed on and
Manual Tuning mode by keying in the frequency of off), your select the input signal and pressing the MHz key. In Manual Tuning mode, the instrument will remain locked at the manually tuned frequency after the input signal is turned off.
Help
No
Sensor
Module
A Sensor Module is not required for making
HP
8902A’s INPUT
RF Frequency or
Frequency Error measurements.
Sensor Module, simply
COM& a 500 cable and Type-N adapter the port
To make measurements without a to the output of your signal source. from
HP-/B
The
HP
890214 enables you to fully automate your measurements. Refer to your Hp 8902A Operation and Calibration Manual for setup and programming information.
Time Base
A time base input is provided on the rear panel of the
HP
8902P.. This input allows you to connect the Hp 8902A to an external 10 switches to the external time base and turns
MHz time base. The time base circuitry within the HP 8902A automatically when an external time base of off its time base output suffiaent amplitude (0.5 Vpp) is applied at the input. To verify that an external time base is being used, key in 15.1 SPCL. The instrument will display a 1 if the external time base is being used or a 0 if the internal time base is being used.
2-10 Help
The
HP
8902A has been designed to feed back information about operating status. When the 8902A its detects that the input signal or operating conditions are preventing it from making accurate, reliable measurement, it alerts you by placing an error or dash code in its display.
The circumstances that can cause the HP 8902A to display an error code are classified into one of two categories:
0
Input Problem, caused by input signal conditions, or
0
Operating Problem, caused operating functions. by the selection of incompatible
Certain errors are caused only by an input problem, other errors are caused only by an operating problem, and some errors can be caused by either.
The errors that can be caused only by can be caused an input problem and the errors that only by an operating problem are listed in the chart below.
If your instrument is displaying one of these errors, proceed directly to
Table 2-3. RF Frequency and Frequency Error, recovery action recommended.
Error Codes, and take the
If you did not find your error listed in the chart or
if
your instrument displaying dashes or a questionable measurement, continue with the following procedure. is
1. Press the green function settings that can cause the
HP
key. This cancels all
8902A to display an error code.
2. Compare the operating status
AUTOMATIC OPERATION key of your
HP
8902A after pressing the with the following condition descriptions.
After you have identified the description that best describes your instrument's condition, take the action recommended for that condition.
Help 2-1 1
Same
Error
If the error or reading remains the same after the AUTOMATIC OPERATION key has been pressed, the error is being caused by an input problem. Look
up the error code in Table 2-3 and take the action recommended for
"Input Problem".
No
Error
If the error goes away after the AUTOMATIC OPERATION pressed, the error was caused by an operating problem.
code in Table 2-3 and take the action recommended for
"Operating Problem". key has been
Look up the error
New
Error
If the error is replaced by a different error or dash code after the AUTO-
MATIC OPERATION key has been pressed, the caused by a combined input problem and operating problem. Look up the error code displayed by the instrument after original the error was being
AUTOMATIC OPERATION key was pressed. Take the action recommended for "Input Problem".
Remember
Because of the wide variety of input s i p l s and the operating flexibility of the HP 8902A, it is not possible to list all recovery actions for each error code. After
using
the table to determine the cause of the problem, you may discover other error recovery procedures that are better suited to your application.
2-3. RE Frequency and Frequency Error, Error Codes (1
of
2)
2-72 Help
RF Frequency and Frequency Error, Error Codes (2 of 2)
More about Modulation and
Audio Measurements
/n This Chapter
This chapter introduces the HP 8902A’s special operating capabilities that enable you to adapt its modulation and audio measurements to your specific test conditions. (To use these special capabilities effectively, you should first become familiar with the basic operating capabilities and measurement ranges described in Chapter 1 for the Modulation and Audio measurements.)
This chapter enables you to reference directly to the information you are interested in. The information is organized into three subject areas.
0
Calibration - Refer here for the procedure to calibrate your AM and
FM measurements.
0
Extending Operation - Refer here for the special operating capabilities that enable you to adapt the of your input signal.
HP 8902A to meet the specific conditions
0
Help - Refer here for help in solving setup or operating problems encountered in Modulation or Audio measurements.
The Directory
Use the directory diagram below to quickly locate the subject you are interested in. A look-up table is located that subject. on the first page of each subject area. Use the look-up table to reference to the topics included for
117 OPERATION 34
3-2 Calibration
Calibration
The HP 8902A meets its specified AM and FM measurement accuracy without needing any additional calibration other than the recommended procedure performed annually to re-calibrate the entire instrument. The following calibration procedure allows you to further enhance the accuracy of your AM and FM measurements, however.
AM
and
FM Calibration
By making comparative measurements against a known modulation level (provided by the AM/FM CALIBRATION output port), the instrument creates a calibration factor that can be used to minimize measurement error. Once the calibration factor has been created, you have control over when it is used by the instrument.
(There is not a calibration procedure for the <PM measurement.)
The following chart lists the special function codes for enabling, disabling, or displaying the calibration factor. After you have enabled the calibration factor, the HP 8902A will automatically apply it to its AM or
FM measurements.
Note
To ensure the highest possible measurement accuracy, allow the
HP 8902A to warm up at least thirty minutes before performing the calibration procedure. Also, to ensure that the measurement circuitry is fully settled, allow the HP 8902A to update the calibration factor at least three times before completing the calibration procedure. (The calibration factor is updated approximately every 17 seconds while the Calibrator is on.)
Calibration 3-3
Remember
1. Connect the HP 11722A Sensor Module (or a 50 ohm cable and Type-N adapter) from the INPUT 50R port to the AM/FM
CALIBRATION output port (lower left corner on front panel).
2. Press the AM or FM key to select the measurement you wish to calibrate. You will need to repeat this entire procedure twice if you wish to calibrate both your AM and FM measurements.
3. Press the CALIBRATE key to turn on the Calibrator. Wait for the
Calibration Factor to be displayed. The calibration factor will be displayed as a percentage. This percentage indicates the relationship between the HP 8902A's measurement and the actual output of the Calibrator. (For example, a calibration factor of 100% indicates that the measured value is exactly the same as the calibrator output value. Likewise, a calibration factor of 100.17% indicates that the
HI' 8902A is measuring .17% above the Calibrator's actual output.)
While the HP 8902A is in the Calibration mode (Calibrator key lit), the calibration factor is stored in the instrument's non-volatile memory each time it is updated (approximately every 17 seconds). To ensure that the measurement circuitry is fully settled, allow the instrument to update the calibration factor at least three times before proceeding.
4. Press the Blue Shift key and then the SAVE CAL key (only when in the Calibration mode) to enable the calibration factor
(the same as entering 16.1 or 17.1 SPCL when not in the
Calibration mode). Wait for the calibration factor to be displayed.
5. Press the CALIBRATE key to turn procedure is complete. You can off now the Calibrator. The calibration connect the HP 8902A to your signal source and be assured that you are making the most accurate modulation measurements possible with the HI' 8902A.
3-4 Extending Operation
Check Tuning
For most applications, the HP 8902A’s Auto Tuning mode enables the instrument to automatically tune to the input signal. (Auto Tuning mode is the right choice for measuring modulation on a single, stable carrier.)
The HP 8902A will inform you that it is having difficulty tuning by placing dashes, error codes, or a very inaccurate reading in its display.
Extending Operation 3-5
You can check what frequency the HP 8902A is currently tuned to at any time during the measurement by pressing the Blue Shift key and then the
DISPLAY FREQ (fikHt) key. A way to ensure that the instrument is tuned to the desired frequency is to manually tune it by keying in the input frequency and then pressing the MHz key. (If you are interested in details on how the instrument operates in its Manual Tuning mode, refer to Chapter 2.)
increasing Selectivity
The selectivity of your modulation and audio measurements above 10 MHz can be increased by selecting the 455
455 kHz kHz IF. Key in
IF with a 200 kHz bandwidth, or key in 3.7
3.1 SPCL to select the
SPCL to select
IF with maximum selectivity of 30 kHz. (Note that the 455 kHz
455 kHz
IF should only be selected for measuring modulation rates below 10 kHz.) To further increase the selectivity of your measurement, select low-pass, high-pass, or bandpass audio filtering using the Audio Filter keys on the front panel.
The HP 8902A's Auto Tuning mode is able to automatically find and tune to the fundamental in a harmonically-rich spectrum as long as the fundamental is at least 10 dB above the level of the second and third harmonics. The HP 8902A will also auto tune to the carrier if the carrier is at least 30 dB above all non-harmonically related RF signals. If, however, your input signal does not meet these criteria, the HP 8902A may have difficulty auto tuning to the carrier. If the HP 8902A tunes to a signal other than the carrier, it will cause the instrument to display modulation and audio readings for that signal rather than the carrier.
To check what RF frequency the HP 8902A is actually tuned to, press the FREQ key. If the instrument does not display the correct carrier frequency, manually tune the HP 8902A to the carrier frequency; key in the frequency of the carrier and then press the MHr key. (Refer to
Chapter 2 for details on the Auto Tuning and Manual Tuning modes.)
Changing
Frequency
Although the HP 8902A is not designed for swept measurement applications, its Auto Tuning mode does enable it to automatically search for the carrier signal when carrier frequency is changed. (For details on the capabilities and limitations of Auto Tuning mode operation, refer to
Chapter 2.)
3-6 Extending Operation
Noisy Carrier
Excessive noise or low-rate (below 20 Hz), high-deviation (greater than 400 kHz) FM on the carrier signal can make it difficult for the HP 8902A to auto tune to the carrier. If you know that your carrier is noisy, or if the HP 8902A indicates it is having difficulty setting up the measurement by continuously displaying four dashes, manually tune the HP 8902A to the carrier frequency. Simply key in the frequency of the carrier and then press the MHz key. If the
HP 8902A does not display a measurement reading, press the TRACK
MODE key. (Refer to Chapter 2 if you are interested in details on how the instrument operates in Manual Tuning mode and Track mode.)
Drifty Carrier
The HP 8902A is able to track drifting or noisy RF signals without sacrificing measurement bandwidth or level sensitivity. A drifting input signal can cause the instrument to continuously display four dashes (Auto Tuning mode) or display Error 01 (Manual Tuning mode). Press the TRACK MODE key to select the wide IF-bandwidth track mode function. Track Mode can be selected with either the Auto or Manual tuning modes. Note that the
Track Mode function reduces the low frequency response of modulation measurements and increases the level of residual modulation. (For details on the capabilities and limitations of Track Mode operation, refer to Chapter 2.)
Frequency Overrange
There are three techniques for extending the HP 8902A's frequency range above 1300 MHz: internal harmonic mixing, external local oscillator and mixer down-conversion, and down-conversion with a spectrum analyzer. All three techniques extend the AM, FM, and @M measurement capabilities of the HP 8902A to microwave frequencies. Refer to Chapter 5 for measurement examples using these tuning techniques.
Frequency Underrange
The specified low frequency limit of the HP 8902A is 150 kHz.
However, you can extend this measurement range to below 50 kHz. The procedure is simple. First, manually tune the HP 8902A to 100 MHz and override Error 01 by keying in 8.1 SPCL. This enables the input signal to pass directly through the input mixer without frequency conversion. Next, suppress IF feedthrough by selecting the 3 kHz or
15 kHz low-pass filter. The analyzer is now ready to make modulation measurements. If you wish to display the carrier frequency, key in 34.0
SPCL (press the AM key to return to the AM measurement mode).
Extending Operation 3-7
lncreasing Sensitivity
Two dashes or 0 MHz in the display indicates that the level at the input signal is below the HP 8902A's present measurement range.
However, the HP 8902A's special function capabilities enable you to make modulation and audio measurements on carrier signals down to -75 dBm.
The special function codes and their respective ranges are shown in
Diagram 3-1. (Keep in mind that these special functions add gain in
the RF and IF paths. Enabling them for an input signal that exceeds the
designated range for that special function (as shown in Diagram 3-1)
may cause the instrument to overrange and display Error 02.) If you do not know the output level of your source, sequence through the ranges until the HP 8902A displays a measurement reading.
-
+20
0
9
>
-20
-40
-60
"1 25
1.7
I
40
9.3 SPCL
'
(20 i
1
100
INPUT FREQUENCY (MHz)
A
1000 1300
Diagram 3-1. Typical Modulation and Audio Measurement Ranges
Unstable Carrier
If you are measuring modulation on a carrier signal whose RF level does not remain above -20 to -25 dBm (for example, a carrier that is being pulsed on and off), select the Manual Tuning mode by keying in the frequency of your carrier signal and then pressing the MHz key. In Manual
Tuning mode, the instrument will remain locked at the frequency of the carrier after the carrier is turned off. (For details on the instrument's operation when in the Manual Tuning mode, refer to Chapter 2.)
3-8 Help
Help
No Sensor Module
A Sensor Module is not required for making modulation or audio measurements. To make measurements without a Sensor
Module, simply connect a 50 R cable and Type-N adapter from the HP 8902A's INPUT port to the output of your signal source.
HP-IB
The HP 8902A enables you to fully automate your modulation and audio measurements. Refer to your HP 8902A Operation and
Calibration Manual for set-up and programming information.
Time Base
A time base input is provided on the rear panel of the HP 8902A. This input allows you to connect the HP 8902A to an external time base. The time base circuitry within the HP 8902A automatically switches to the external time base and turns off the time base output when an external time base of sufficient amplitude at the input. To
(0.5 Vpp) is applied verify that an external time base is being used, key in 15.1 SPCL. The instrument will display a 1 if the external time base is being used or a 0 if
10 MHz the internal time base is being used.
Solving Measurement
Problems
The HP 8902A has been designed to feed back information about its operating status. When the HP 890214 detects that the input signal or operating conditions are preventing it from making an accurate, reliable measurement, it alerts vou bv Dlacine an error or dash code in its disdav.
Help 3-9
The circumstances that can cause the HP 8902A to display an error code are classified into one of two categories:
0 input Problem, caused by input signal conditions, or
0
Operating Problem, caused by the selection of incompatible operating functions.
Certain errors are caused only by an inpuf problem, other errors are caused only by an operating problem, and some errors can be caused by either.
The errors that can be caused can be caused only by an input probIem and the errors that only by an operating problem are listed in the chart below.
If your instrument is displaying one of these errors, proceed directly to
3-1. Modulation and action recommended.
Audio Error Codes and take the recovery
If you did not find your error listed in the chart, or if your instrument is displaying dashes or a questionable measurement, perform the following procedure.
1. Press the green AUTOMATlC OPERATION key. This cancels all function settings that can cause the €4" 8902A to display an error code.
2. Compare the operating status
AUTOMATIC OPERATION key of your with
HP
the
8902A
after
list pressing of the conditions.
After you have identified the description that best describes your instrument's condition, take the action recommended for that condition.
Same
Error
If the error or reading remains the same after the AUTOMATIC OPERATION key has been pressed, the error is being caused by an input problem.
Look up the error code in Table
"Input Problem".
NO Effof
If the error goes away after the AUTOMATIC OPERATION key has been pressed, the error was caused by an operating problem. Look
and take the action recommended for
"Operating Problem".
3-70 Help
New Error
If the error is replaced by a different error or dash code after the
AUTOMATIC being caused
OPERATION key has been pressed, the by original
Look up the error code displayed by the instrument after the error was a combined input problem and operating problem.
AUTOMATIC OPERATION key was pressed. Take the action recommended for “Input Problem”.
Remember
Because of the wide variety of input signals and the operating flexibility of the recovery actions
HP
it is not possible to list all error code. After using the table to determine the cause of the problem, you may discover other error recovery procedures that are better suited to your application.
Table 3-7 Modulation and Audio Error Codes (1 of 3)
-mY
02
Table 3-1 Modulation and Audio Error Codes (2 of 3)
Input circuits overdriven.
. . I tnpuz- increase RF input operating-
3-12 Help
~ ~~~
and Audio Error Codes (3 of 3)
More about RF Power and
/n this Chapter
This chapter introduces the
HP
8902As that enable you to adapt its RF Power and Tuned measurements to with the basic operating capabilities and measurement ranges described in your
Chapter 1 s p e d operating capabilities specific test conditions. for the you
RF Power and
(To
RF use these should first become familiar
TRFL
Level (TRFL) measurements.)
This chapter enables you to reference directly to the information you are interested in. The information is organized into three subject areas.
0
Calibration
-
Refer here for information about the
TRFL calibration technique.
RF Power and
0
0
Extending Operation that enable you to adapt the of your input signal.
- Refer here for the special operating capabilities
HP 8902A to meet the specific conditions
Help
-
Refer there for help in solving setup or operating problems encountered in RF Power or TRFL measurements.
The Directory
Use the directory diagram below to quickly locate the subject
Use you the look-up table to reference to the topics included for are interested in. A look-up table area. that subject. is located on the first page of each subject
In
OPERATION
4-2 Calibration
Calibration
RF Power Calibration
The RF Power calibration procedure is shown in Chapter 2 of this guide. Once the procedure has been completed it does not need to be repeated again unless you change Sensor Modules or the calibration factors for the Sensor Module you are using change (due to repair or recalibration of the Sensor Module). (If the Sensor Module or the calibration factors are changed, you will need to complete the calibration factor entry procedure provided in Appendix proceeding with the calibration procedure shown in
B before
Chapter 1.)
To Maintain Accuracy
To maintain calibration accuracy, it is necessary to periodically press the
ZERO key (approximately once every ten minutes while making RF Power measurements is recommended and each time you connect the sensor to a different output port). Pressing the ZERO key enables the HP 8902A to compensate for any inherent, dc-offset error in the measurement system caused by changes in the ambient operating temperature.
Tuning
You may remember that in Chapter 2 you were told that the HP 8902A should be tuned to the frequency of the input signal when making RF
Power measurements. Even though the RF Power measurement is not a tuned measurement, the instrument uses the frequency setting to determine the appropriate calibration factor to select from the table of power sensor calibration factors stored in its memory. (If a calibration factor is not stored for the specific frequency being measured, the HP 8902A derives a calibration factor by linear interpolation between the closest cal factors in the storage table on both sides of the measurement frequency.)
TRFL
Calibration The TRFL calibration procedure is described in Chapter
will help you remember the key steps to calibrating your TRFL measurements.
Table 4-1. Tuned RF Level Calibration Procedure
Cafibrdon 4-3
The IF Synchronous Defector
The calibration procedure described measurements using the HP in Chapter
8902As IF
I enables you to make
Synchronous
Synchronous detector makes a very narrow band (200 measurement and provides the greatest
(-127 dBm). (The
HP
8902A.)
IF Synchronous
TRFL detector is detector. The
Hz)
IF measurement sensitivity
TRFL
the default selection for the
The
IF
Average Defector
A second detector is also available for making TRFL measurements.
This detector
4.4 is the IF Average detector and it
to calibrated is
SPCL. After you have selected the IF Average detector, perform the your selected by keying in
TRFL measurements.
The measurement bandwidth of the IF Average detector is set by a 30 kHz IF filter. (A 200 kHz IF filter can also be selected, refer to Increasing Selectivity in this chapter for details). The ,increased measurement bandwidth of the IF Average detector reduces its measurement sensitivity to less than that of the IF Synchronous detector.
shows a comparison of the measurement ranges for the IF Synchronous detector and the IF Average detector.) Key in
4.0 SPCL when you wish to reselect the IF Synchronous detector.
Remember
Diagram 4-1. The Measurement and IF Average Detectors
Ranges for the IF Synchronous
The Calibration Technigue
You may remember, that in the
Chapter levels
I
(0, you were instructed
-40, and -80 dBm measurement ranges for the the input signal to each of
).
IF
TRFL to calibration procedure in adjust the input signal to specific
Note in
Synchronous detector. When you adjusted these levels the display was lit and you were instructed to
RECAL that each of the specified levels is within the overlap (calibration) region between two RF annunciator in the press the CALIBRATE key.
Range I
When you pressed the CALIBRATE key to calibrate Range 1, the flp measured the level of the input signal twice. Once using its RF Power
890244 meter circuitry and once using the IF Synchronous detector and the
Range 1 arcuit configuration. By comparing the two measurements, the
HP 8902A created a TRFL calibration factor for Range 1 that equated the Range 1 measurement to the calibrated RF Power measurement. This measurement to all Range 1 TRFL measurements made at that frequency.
This double measurement technique makes it very that the level of the input signal remain stable throughout the calibration process (while the CALIBRATE key important is lit).
Caiibraticm 4-5
Relative TRFL Measurements
The
This transfer uncertainty can be eliminated by using the HP 8902As
SET
RF Power measurement-to-Range 1 transfer uncertainty is f0.06
REF mode to make relative power measurements. When the dB.
REF key is pressed, the
HP
8902A
SET establishes the current level of the input signal as the enables the such as
HP
0 dB-reference for Range
8902A
1. The SET REF mode to measure relative level changes of linear devices, attenuators, directly and accurately. (Refer to example
Chapter 5 for of how the SET REF mode is used for attenuator testing.) an
Ranges2and3
The double measurement calibration technique is also used to transfer measurement accuracy from Range 1 to Range 2 and
Range 3. The Range uncertainty is f0.04
1 to Range dB.
2 and Range 2 from to Range 3
Range 2 to transfer
IF Ranges
In addition to the operating changes that occur within the to produce the three RF measurement ranges, changes that occur within each of the three
These changes occur as and as the selected IF
10 dB amplifiers in the range. Because the amplifiers and IF its than
15 i0.02
HP also
8902A operating measurement ranges.
IF path are switched in, dB measurement detector are very linear, the typical range-to-range error for the amplifiers is and detector linearity uncertainty (for the IF Synchronous detector) is less than f0.02 dB over each RF
RF less dB per change, measurement range (1 through 3).
TRFL
Accuracy
Although calculating precise measurement uncertainty for a
TRFL
measurement can involve several uncertainty factors, Graph 4- 1 demonstrates that even for worst case the total TRFL measurement uncertainty is minimal.
1.5 m^
9
1.0
2
0.5
0.25
-13 0 -20 -40 -60 -80 -100 -120
R f W E 1 (dBm)
'RSS = Root Sum of the Squares
Graph 4-1. Tuned RF Level Measurement Accuracy.
4-6 Extending Operation
Extending
Operation
Extending Operation 4-7
Tuning
HP
RF Power and TRFL calibration techniques require that the
8902A is tuned to the frequency of the input signal.
As
shown in
Chapfer I, frequency there are of two ways to tune to the input signal. If you know the your input signal, the most direct way to tune is in the frequency of do not know the input frequency, set the input signal level to between
0 and -20 dBm, then press the FREQ key, the Blue Shift key, and the AUTO
TUNING key on the the input signal and then pressing the
HP 8902A. When the HP by keying key. If you
8902A displays the frequency of the input signal, press the MHr key to select Manual Tuning, and then re-enter the TRFL measurement mode and proceed with your measurement. increasing
Selecfivify
To minimize the possibility of unwanted
TRR.
low frequency and spurious signals entering the passband bandpass IF filter can of
IF Average detector, the the
shows the filter configurations possible for the TFGL measurement.) Remember that when using the
IF measurement, a high-pass
RF filter and filters determine measurement bandwidth. (Be sure to select the desired filters before performing the "RFL calibration.)
Table 4-2. Filter Configurations
, wHig- filter
(5925-1
OUT
. wide
IF
Nammr
Fitter
FaeY
(30-Bw)
Automatic Selection
IF
seqyenoe
3.0 SPCL
4-8 Extending Operation
You can quickly repeat TRFL measurements at various frequencies using the HP 8902A‘s eight storage registers. After you have completed the
TRFL calibration procedure at a given frequency, set the level of the input signal to between measurement Range and a digit key (1 -8)
1).
0 and -20 dBm
Then press the
(so that the HP 8902A is in
Blue Shift key, the STORE (7) key to store the instrument’s complete operating condition including calibration data into one of the instrument’s storage registers.
All of the HP 8902As current operating conditions including calibration data will be retained in the selected storage register through power down.
Whenever you wish to repeat the TRFL measurement at the given stored frequency, select the appropriate register by pressing the Blue shift key, the RECALL (8), key and the appropriate digit key. The instrument will restore all of its operating conditions to the configuration that existed when the storage register was selected. This means the instrument is once again configured to make TRFL measurement at the previously calibrated frequency. (Keep in mind that calibration is not source dependent; that is, once the HP 8902A has been calibrated at a given frequency it can be used to measure your other signal sources set at the same frequency as well.)
Noisy Signal
If the input signal is noisy, unstable, or has greater than 100 Hz FM, the narrow-band IF Synchronous detector may have difficulty remaining locked to the input signal. The instrument will indicate that the input signal is not stable enough for the by continuously displaying six dashes, or by alternating four dashes in its display. To measure the the wider-band IF
IF Synchronous detector to tune to
TRFL
Average detector by keying in 4.4 six
SPCL. dashes then of noisy signals, select
After the IF
Average detector is selected, the calibration procedure is the same as for the IF Synchronous detector (as shown in Calibration in this chapter). (Note that the IF Average detector must be selected prior to calibrating Range 1.)
The measurement bandwidth of the IF Average detector is determined by the IF filter selected (refer to lncreasing Selectivity for filter information).
For added noise correction when using the IF Average detector to measure low-level signals, key in 31.1 SPCL* when you select the
3 (-60 to -100 dBm) which it uses to
IF
Average detector (that is prior to calibrating Range 1). (This function should only be used when a Sensor Module is being used with the
HP 8902A.) This function causes the instrument to create an additional calibration factor for Range compensate for any residual noise inherent within the measurement system.
The noise correction function (3 1.1) is maintained through instrument power down. To turn off noise correction, key in 31.0 SPCL.
* This capability is available on instruments serial prefixed 2535A and above.
Extending Operation 4-9
Drifty Signal
If the input signal is drifting, the IF Synchronous detector may have difficulty remaining locked to the input signal. The instrument will indicate that it is having difficulty by placing six dashes or Error 01 in its display.
The wider measurement bandwidth of the IF Average detector makes it more tolerant of signal drift. Press the green AUTOMATIC
OPERATION key and then key in 4.4 SPCL to select the IF
Average detector for your TRFL measurements. (Note that the
Track Mode function is not available for TRFL measurements.)
Frequency Overrange
There are three techniques for extending the HP 8902A's frequency range above 1300 MHz; internal harmonic mixing, external local oscillator and mixer down conversion, and down-conversion with a spectrum analyzer. All three techniques extend the measurement capabilities of the HP 8902A to microwave frequencies. Refer to
Chapter 5 for measurement examples using these tuning techniques.
Frequency Underrange
The specified low frequency limit of the TRFL measurement is 2.5 MHz.
However, you can extend this measurement range to approximately 900 kHz; the procedure is simple. Connect your signal source to the HP 8902A and adjust the source level to between 0 and -20 dBm. Press the Blue
Shift key and the INSTR PRESET key on the HP 8902A. Manually tune the HP 8902A to 5 MHz. When Error 01 is displayed, select the TRFL measurement. Manually tune the HP 8902A to the frequency of the input signal. When the signal level is display, proceed with TRFL calibration.
Low-Level Signa/
To measure the between 0 and
TRFL
-20 can be set between of a signal source that can not be set to a level dBm, simply use a second signal source whose level
0 and -20 dBm to perform the calibration procedure.
Connect the HP 8902A to the second signal source and adjust the signal source frequency to the frequency of the signal to be tested. After you have completed the calibration procedure using the second source, reconnect the HP 8902A to the signal source to be tested and measure its TRFL.
Input impedance
To improve the SWR characteristics of your TRFL measurements, an internal, fixed
Inserting this pad enables the HP 8902A to maintain a constant input impedance over its entire measurement range. Key in 1.9 SPCL to insert the fixed
10 dB pad can be inserted at the INPUT of the HP 8902A.
10 dB pad. (Note that the SPCL key does not remain lit.) The instrument continues to operate in its Automatic Operation mode except that the 10 dB pad is now always inserted. (Note that
Special Function 1.9 decreases the sensitivity of Range 3 by 10 dB.)
4-1 0 Help
Help
bw
Term
If you are replacing the Sensor Module with another Sensor Module, refer to Appendix calibration data
B
in this guide for the procedure for entering the for the new Sensor Module into the
HP
890214.
Short Term
If you are only using the new Sensor Module temporarily, you can manually enter the appropriate cal factor for each RF Power measurement.
(Refer to your
HP
8902A Operation and Calibration Manual for the procedure and considerations for manually entering cal factors.)
Help 4-11
Interchangeably
If you plan to use table is available in the HP is designed to be used in the instrument’s Frequency Offset Mode.
(In this mode an external local oscillator (LO), a microwave down- converter, and a mixer are typically used to extend the frequency range of the HP two sensors interchangeably, a second storage
8902A.
8902A’s non-volatile memory. This table
Refer to your HP 8902A Operation and
Calibration Manual for details on using the Frequency Offset Mode.)
By specifying an offset frequency of zero, the Frequency Offset table can also be accessed for measurements when an external used. Simply key in 27.3 SPCL and then 0 MHr (the fOFS annunciator will light in the display). The instrument is now ready to store the calibration factors (up to 22)
LO is not being for the second Sensor Module in the
Frequency Offset table using the entry procedure shown in Appendix B.
Once the cal factors have been stored, key in 27.0 SPCL when you wish to exit the Frequency Offset Mode and use the first Sensor Module. To re-enter the Frequency Offset Mode and use the second Sensor Module, key in
27.1 SPCL.
No Power Sensor
RF Level (uncalibrated)
To make an uncalibrated sensor, connect a
INPUT port to the output of your signal source. Press the RF POWER key. The HP 8902A measurement using its lights the SPCL key rather than the the uncalibrated RF will make an uncalibrated broadband power
RF Peak detector. (Note that the HP
RF POWER
8902A key when it is using
Peak detector to measure power.) Although the accuracy of this measurement is significantly lower than a calibrated power measurement made using a power sensor, it can be useful as a means
HP of
50R
RF power measurement without a power cable and Type-N connector from the HP determining if there is any input signal present at the
8902A’s input. If a Sensor Module is connected to the HP the RF Peak detector can be selected by keying in 35.0 SPCL.
8902A‘s
8902A,
Tuned Level (uncalibrated)
To make an uncalibrated Tuned Level measurement (either with a Sensor
Module connected to the HP 8902A or with a BNC cable and Type-N connector connected at the INPUT port) tune the HP 8902A frequency of the input signal and key in 36.0 SPCL. The HP to the
8902A make an uncalibrated Peak Tuned Level measurement. Although the accuracy of this measurement is significantly lower than a calibrated will
TRFL measurement, it can be useful for measuring input signals that are drifting.
4-12 Help
TRFL (calibrated)
The relative power measurement mode (SET REF) allows you to make calibrated TRFL measurements without using a power sensor.
An example of this measurement technique is provided in Chapter 5.
HP-/B
The HP 8902A enables you to fully automate your RF Power and
TRFL measurements. Refer to your HP 8902A Operation and
Calibration Manual for set up and programming information.
Time Base
A time base input is provided on the rear panel of the HP 8902A. This input allows you to connect the HP 8902A to an external 10 MHz time base reference. The time base circuitry within the HP 8902A automatically switches to the external time base and turns off its time base output when an external time base of sufficient amplitude (0.5 Vpp) is applied at the input. To verify that an external time base is being used, key in 15.1 SPCL. The instrument will display a 1 if the external time base is being used or a 0 if the internal time base is being used.
The fundamental difference between the RF Power and TRFL measurement is their measurement bandwidth. The measurement bandwidth for the RF
Power measurement is set by the bandwidth of the power sensor being used. For instance, the measurement bandwidth of the power sensor used in the HP 11722A Sensor Module is 4 GHz, therefore the RF Power measurement bandwidth of the HP 8902A is 4 GHz when used with the
HP 11 722A. Select the RF Power measurement when you wish to measure total power of all modulation, sidebands, harmonics, and spurious on the signal (as you would using an HP 436A or HP 438A type power meter).
The measurement bandwidth of the TRFL measurement is much narrower than that of the RF Power measurement. When the IF Synchronous detector is used to make a TRFL measurement, measurement bandwidth is 200 Hz.
When the IF Average detector is selected, measurement bandwidth is determined by the bandwidth of the IF filter being used (30 kHz or
200 kHz). (The 30 kHz filter is automatically chosen by the instrument when the IF Average detector is selected; refer to increasing Selectivity in this chapter for filter selection information.) The IF Average detector measures the total power of the signals and noise present within the IF filter passband. Select the TRFL measurement mode when you want to make calibrated tuned level measurements of discrete input signals.
HeJP 4-13
Sensitivity
The most apparent difference between the TRFL measurement and the RF offered by the measurement bandwidth, is the increased measurement sensitivity
TRFL measurements detector offer the greatest measurement sensitivity you select the IF measurement sensitivity is determined
IF filter. That is, the 30 than
Power measurement the 200
TRFL measurement. Since sensitivity is directly related to
IF by filter offers using
TRFL the IF Synchronous
(-127 measurements, the bandwidth of
8 dB greater sensitivity measurement sensitivity with the automatically selected 30 the selected kHz dBm
Like other
HP
8902A's RF- measurement is determined by the dynamic range of the power sensor the
+40
HP
RF power meters, the sensitivity of the being used. The dynamic range of the
RF Power measurement can be extend from -70 to dBm. (Refer to your
HP
instance, is -20 to f30 dBm. Using other
8902As
HP
11722A sensors,
Power
Sensor Module, for the sensitivity of
8902A Operation and Calibration Manual for information on which power sensors can be used with the HP 8902A.)
The HP 8902A has been designed to feedback information about its operating status. When the or operating conditions reliable measurement, it to display an are
HP
preventing it from alerts
8902A detects that the input you by making an code in its display. The circumstances that can cause the error code are classified into one of two accurate,
HP
signal
8902A categories:
0
0
Input Problem - caused by input signal conditions, or
Operating Problem operating functions.
- caused by the selection of incompatible
Certain errors are caused only by only by an inpuf problem, other errors are caused an operafing problem, and some errors can be caused by either.
The errors that can be caused can be caused only by an input problem and the errors that only by an operating problem are listed in the following chart.
If
4-3. RF is
Power and action recommended.
TRFL Error Codes errors, proceed directly to and take the recovery
08, 10, 13, 01, 09, 12, 14, 15,
4-14 Help
If you did not find your error listed in the chart, or if your instrument is displaying dashes or following procedure. a questionable measurement, perform the
1. Press the green AUTOMATIC OPERATION key. This cancels all function settings that can cause the HP 8902A to display an error code.
2. Compare the operating status of your HP 8902A after pressing the AUTOMATIC OPERATION key with the conditions described below. After you have identified the description that best fits your instrument’s condition, take the action recommended for that condition.
Same Error
If the error or reading remains the same after the AUTOMATIC OPERA-
TION key has been pressed, the error is being caused by an input problem.
Look up the error code in Table 4-2
and take the action recommended for
”Input Problem”.
No Error
If the error goes away after the AUTOMATIC OPERATION key has been pressed, the error was caused by an operating problem. Look
up the error code in Table 4-2
and take the action recommended for
”Operating Problem”.
New Error
Remember
If the error is replaced by a different error or dash code after the AUTO-
MATIC OPERATION key has been pressed, the original error was being caused by a combined input problem and operating problem. Look up the error code displayed by the instrument uffer the AUTOMATIC OPERATION key was pressed. Take the action recommended for “Input Problem”.
~~ ~~ ~ ~~ ~
Because of the wide variety of input signals and the operating flexibility of the
HP
8902A, it is not possible to list all recovery actions for each error code. After using the table to determine the cause of the problem, you may discover other recovery procedures that are better suited to your application.
Table 4-3. RF Power and TRFL Error Codes (1 of 2)
TRFL circuits being overdriven.
4-16 Help
RF Power and TRFL Error Codes (2 of 2)
5
Measurement Examples
/n
This Chapter
This chapter contains examples of measurement applications using the HP 8902A. The intent of this chapter is to demonstrate the flexib~ty
HP
the measurements,
8902A’s an operating capabilities as measurement capability. understanding described in of the
HP
(To perform
8902As is basic necessary.)
This chapter enables you to reference directly to the measurements you are interested in. The examples are organized into the three measurement groups.
0
0
0
RF Frequency and Frequency Error measurements
Modulation and Audio measurements
RF Power and Tuned RF Level (TREL) measurements
The
Directory
Use the directory diagram below to quickly locate the measurement you are interested in. A look-up table measurement group. Use provided for that group. is located on the first the look-up table to reference page of each to the examples
5-2 RF Frequency and Frequency Error
Low-Level Frequency
Here is a convienient way to measure the frequency stability of low-level signals, below -60 dBm (remember that the Manual measurement sensitivity to -60 dBm). the special function
You
Tuning mode provides may remember that in Chapter 2 codes were given for setting up the instrument for low- level RF frequency measurements. This procedure allows the instrument to automatically select the appropriate special function settings for you.
1. Set the signal source to the desired output frequency and connect it to the to between 0 and
HP
8902A. be adjusted to between dBm. (If the source under test cannot
0 and -20 dBm, use a second source that can be adjusted to perform the
TRFL
of the source measurement first.)
2. Manually tune the HP 8902A to the frequency of the input signal and then select the TRFL level measurements. measurement. In the TRFL, automatically selects the appropriate measurement range settings for low-
3. Decrease the input signal to the level at which you wish to make the frequency measurement. It is not necessary to calibrate the measurement measurement. if you are only interested in making an
TRFL
RF frequency
4.
5.
When the
HP
8902A displays the input signal level at which you wish to measure frequency accuracy, press the RANGE HOLD key on the
HP
8902A.
Select the Frequency measurement on the
HP
8902A. to check frequency error, select the Frequency Error measurement.)
RF Frequency and Frequency Error 5-3
Output Flatness
The following procedure demonstrates a way to use the HP 8902A to characterize the frequency response of RF devices. This technique enables you to accurately characterize output flatness from
100 kHz to 2.6 GHz at levels between -20 and +30 dBm.
1. Connect the HP 8902A and Sensor Module to the output of your
RF signal source. Adjust the source to the frequency at which you wish to establish the reference level.
2.
3.
Select the RF Frequency measurement and press the green AUTOMATIC
OPERATION key on the HP 8902A.
When the HP 8902A displays the frequency of the input signal, select RF Power on the HP 8902A. The previous frequency measurement enables the instrument to automatically select the correct calibration factor for its power measurement. (Use the
LOG/LIN key if you wish to toggle between Watts and dBm units.)
4. Press the RATIO key. This establishes the current measurement level as the reference level.
5. Change the frequency of the signal source, and re-select the RF
Frequency measurement on the
HP
8902A.
6. When the HP 8902A displays the input frequency, select RF Power.
7. Press the Blue Shift key and then the PREVIOUS RATIO (RATIO) key to reference this measurement to the reference level previously set in step 4.
8. Repeat steps 5, 6 and 7 to check output flatness across the output frequency range of your device.
Multi-channel Testing
Use the HP 8902A to quickly measure an evenly spaced multi-channel transmitter (such as a CB radio).
1. Adjust the transmitter to its first (lowest) channel and connect its output to the HP 8902A.
2. Select the desired measurement on the HP 8902A and manually tune it to the frequency of the transmitter's first channel. If the
HP 8902A displays Error 01 (IF Frequency not centered), key in
8.1 SPCL to disable the error so you can read the measurement.
3. Key an increment value into the HP 8902A equal to the channel spacing of the transmitter and then press keys 25 and then the on just press the fi fi kHz kHz fr kHz key. (For example, press the digit key to increment in 25 kHz steps.) From now key each time you want to increment up by 25 kHz.
4.
5.
Adjust the transmitter to its next channel. The HP 8902A will display the measured value for the next channel. (Press the Blue Shift key and the
DISPLAY FREQ key if you wish to check the HP 8902A's tune setting.)
Continue to adjust the transmitter and then increment the HP 8902A to check each of the remaining channels.
5-4 RF Frequency and Frequency Error
frequency Error (PPM)
The HP 8902A's Ratio Mode allows you specifications given in parts-per-million. to verify frequency accuracy
1. Connect the tune €he €3"
HP
8902A to the output of your signal source, and manually
8902A to the expected output frequency of the source.
2. Select Frequency Error on the
10
Hz,
7.1 SPCL.
HP
8902A. To increase display resolution to
3. Key one-tenth into the press the
HP
the manually
8902A and then
RATIO key.) tuned press input the frequency value (from
RATIO step key. (%r example, if the manually tuned frequency was 179.0 MHz, you would key in 17.9 and
1) then
4. The
HP
8902A is now displaying frequency error in parts-per-million.
Frequency Offset Mode
This procedure demonstrates
Offset Mode allows how the Hp you to measure input
8902As signals
Frequency above 1300 MKZ using an external oscillator and mixer. (This is one of three techniques available for extending the RF frequency range of the HP 8902A.
5-1
The other two are shows the setup for also
this
in this chapter.) down-conversion technique.
Diagram 5-1. Setup for Frequency Down Conversion
1. Set the signal source to the desired frequency at an amplitude of about -5 dBm. (The optimum level will depend on the mixer being used; select a level that will prevent mixer compression.)
2. Set the external LO to equal €he output frequency of the signal source plus 120.53 MHz. (For instance, if the signal source frequency was 2.5 GHz, the LO should be set to 2620.53 MHz.) This positions the HP 8902A's internal IF in the center of a tuning octave.
3.
4.
Set the output level of the external LO to +8 dBm.
Press the the external LO frequency, and the key
MHz and then key key on the in
HP
27.3 SPCL,
8902A. you make a mistake, press the CLEAR key and re-enter the keystrokes.
Moduleton and Audio 5-5
5. Manually source by tune the keying
HP in
8902A to the expected frequency of the source frequency and then the signal pressing the MHt key.
The Manual Tuning Mode is always the right choice for this measurement technique.
6. Now select the desired measurement on the or Tuned RF Level measurements, the calibration factors for the
Sensor Module that you are using need to be stored in the Frequency Offset cal factor storage table. Refer to Appendix B
HP 8902A. for the storage procedure.
7. When you want to exit the same external LO the Frequency Offset Mode, key in
If you wish to re-enter the Frequency frequency set in
Offset step
Mode
4, and key in maintain
27.1 SPCL.
SPCL
Tone
Bursf
FM
This procedure enables you to configure the
HP
890244 as a
Tone Burst receiver by setting a time delay between when the
HP 8902A senses an RF signal at its INPUT and when it enables the output at the MODULATION OUTPUT/AUDIO INPUT port.
1. Conned y o u transmitter (modulated source) to the HP 8902A’s
Connect an audio counter to the MODULATION OUTPUT/AUDIO port.
INPUT
2.
3.
Press the FM key on the Hp 8902A.
Select a detector, and filter. if desired, Audio Filters, and an FM De-Emphasis
4. Key on the transmitter. Allow the HP 8902A to range and tune automatically.
5-6 Moduiation and Audio
5.
6.
Press the RANGE HOLD key to hold all ranges and tuning.
Key in 18." SPCL to set the time delay. Where NN equals the desired delay in milliseconds (from 1 to 99). (For instance, if a 5ms delay is desired, enter 18.5 SPCL, if a 50ms delay is desired, enter
18-50 SPCL.) The speaal function value will remain in the display.
7. Key on the transmitter. The audio counter should display the modulation rate present at the end of the delay period.
Residual Modu/afjo#
FM
is a measure of the hum and noise of the unmodulated transmitter. For as the ratio of mobile the output of transmitters, hum and noise is defined a standard receiver with de-emphasis when the transmitter is modulated and then unmodulated. (Hum and noise is usually expressed in dB referenced to 3
1. Connect your transmitter to the kHz peak deviation.)
HP
8902A and turn off FM modulation.
2. Press the 50 Ht HP filter key. The 50 for this measurement. The Hp
Hz
8902As high-pass filter is recommended that it can measure the hum and noise of most transmitters directly.
shows the typical residual FM is low enough characteristics for the HP 8902A.
3. Press the filter attenuates a 1 kHz key and then the 750ps 750ps signal by 13.66 dB (a factor of 0.2076).
4.
5.
Press the FM key on the
HP
8902A to measure residual FM.
RMS
Blue Shift key and the RMS (AVG) key. This selects the true
6. Key in .44 and then the ratio reference is
RATfO
0.440 (that is, key. For standard modulation, the
3.0 X 1/fi X 0.2076 = 0.440).
7. Use the LOG/LfN key to select dB units. The display now indicates FM hum and noise in dB relative to 3 kHz peak deviation.
0 200 400
FREQUENCY (MHz)
600
-40
2
p
-50 k!
N
3
-M)
E),
W % cd
f
-70
-80
0 t 1 I I I I
200 400 600 800
FREQUENCY (MHz)
1000 1200
15 kHz Low-Pass Filter
Diagram 5-2. Typical HP 8902A Residual FM Characteristics
Modulation and Audio 5-7
SlNAD
The HP 8902A allows you to make SINAD measurements (at 1 kHz or
400 Hz) on the internally demodulated audio signal or on an external audio signal applied to the MODULATION OUTPUT/AUDIO INPUT port.
Demodulated Audio
1. Connect your modulated signal source to the HP 8902A's INPUT port.
2. Select the appropriate modulation mode (AM, FM or QM).
3. Key in 29.0 SPCL,
DISTN (PEAK+) the Blue Shift key, and then the 1 kHz or 400 Hz DISTN (PEAK-) key. An annunciator in the display indicates which frequency is being measured.
4. Use the LOG/LIN key if you wish to toggle between % and dB units.
5. Press the appropriate Audio Filter keys to set the desired measurement bandwidth for the internally demodulated audio signal.
External Audio
6. Connect your audio source to the MODULATION OUTPUT/AUDIO
INPUT port on the HP 8902A.
7. Press the AUDIO INPUT key (key should remain lit).
8. Perform steps 3 and 4 above to measure the SINAD of the external audio signal.
Signal-to-Noise
The HP 8902As such
FM transmitters.
Ratio Mode makes it easy to make relative measurements as signal-to-noise on AM transmitters or hum and noise on
1. Connect your signal source to the the modulation off.
INPUT
2. Select the appropriate modulation measurement on the HP 8902A, (AM, or FM) and the RMS detector.
3. Press the RATIO key to establish the unmodulated input signal as the reference measurement.
4. Press the LOG/LIN key if you wish to toggle between % and dB units.
5. Turn on the modulation at the modulation source. The HP 8902A will compute and display the signal-to-noise ratio.
5-8 Modulation and Audio
Modulation Flatness
The Hp 8902As Ratio Mode makes it easy to make relative measurements such as modulation flatness.
1. Connect your modulated source to the
HP
8902A’s INPUT.
2.
(AM, FM, @MI. on the
HP
8902A,
3. Key in a reference modulation and press the RATIO key. (For instance, press or 3
3 kHz FM signal
RATIO deviation.) Or, key to establish a reference of 3% AM depth, simply press the present at the
RATIO
8902A’s key by itself to as the reference.
4.
5.
Press the LOG/UN key if you wish to toggle between
O h and dB units.
Vary the modulation rate of your source across the audio spectrum. The
HP
8902A will display modulation flatness as the change in measured modulation relative to the reference.
SA DowfiConversion
The measurement range
HP of the HP 8902A can be extended above
1300 MHz for modulation and audio frequency measurements by using a spectrum analyzer as of three techniques available for extending the of the 8902A. a fixed-tuned receiver.
The other two are also
(This is one
RF frequency range shown in this chapter.)
1. Connect the signal shown above. source, spectrum analyzer and
HP
8902A as
2. Tune the spectrum
MHz). analyzer to the output frequency of the signal source.
Set the spectrum analyzer in its zero span mode with linear detection, and select a resolution bandwidth that is wide enough to pass the input signal
(e.g. 3
3.
4.
Adjust the spectrum analyzer fine frequency control to peak the signal on the spectrum analyzer display.
Tune the
HP
8902A to the IF output frequency of the spectrum or audio measurement.
(Note that residual FM measurements will generally be limited by the phase noise characteristics of the spectrum analyzer’s local oscillator.)
RF Power and TRFL 5-9 and
TRFL
This measurement technique will enable you to measure the relative level change of devices, such as attenuators, directly and accurately.
Diagram 5-3.
1. Tune the signal source to the desired frequency.
2. Set the level of and connect it to the
HP
signal
8902A. from the device under test to 0 dBm
3. When the
HP
8902A displays the input signal frequency, press the key, the gold S key, and then the Tuned RF Level key on the
HP
MHt
8902A.
5-10 Rf Power and TRfL
4. After the measurement has settled, press the Blue Shift key and the SET REF (ZERO) key. This establishes the current input level as the 0 dB reference for the TRFL measurement.
Note that the RECAL and UNCAL annunciators are now off.
Press the LOG/LIN key if you wish to toggle between % and dB. 5.
6. Begin stepping down the output level
RECAL annunciator is displayed. of the device under test by increments of 10 dB or less. Press the CALIBRATE key each time the
7. When you want to exit the relative measurement mode, key in 26.0
SPCL. Key in 26.1 SPCL if you wish to re-enter the relative measurement mode and continue to use the previously established 0 dB reference.
Low-Level Signals
This procedure will enable you to measure low-level signals that can not be adjusted to between 0 and -20 dBm (such as spurs) down to
-110 dBm; even in the presence of larger signals as close as 2 MHz.
This example also demonstrates how the Store and Recall functions help you quickly repeat TRFL measurements at various frequencies.
1. Connect the HP 8902A to a signal generator and adjust its output to 0 dBm at the frequency of the spurious signal.
2. Manually tune the HP 8902A to the input signal and perform the
TRFL calibration. Performing TRFL calibration is actually optional.
If you do not perform the calibration, the HP 890214 will make uncalibrated measurements with approximately f
3. When the TRFL calibration to between 0 and -20 dBm. is complete, return the signal generator level
4. Press the Blue Shift key, the STORE (7) key, and the 1 digit key. This stores the current frequency setting and calibration data in register 1.
Repeat steps 1 through 3 at the frequency of each spur to be tested
(up to eight). (If you wish to check more than eight frequencies, use an external controller and the 38.N special functions to create a TRFL calibration factor data base and the 39.N special functions to re-enter the calibration factors as they are needed to check each frequency.)
5. Connect the HP 8902A to the spur source, and press the the RECALL (8) key and the 1 digit key. This causes the instrument to spur. Press the dBm units.
LOG/LIN
Blue Shift key if you wish to toggle between Watts and key, recall the frequency setting and TRFL calibration data stored in register 1.
The HP 8902A now automatically ranges to and displays the level of the
RF Power and TRFL 5-11
Noisy Source
5-4 TRFL extremely noisy signal source. Using measurements for an
this
setup, signal levels with many MHz of residual FM deviation can be measured to -100 dBm.
Diagram 5-4. Setup for Measuring the
Noisy Source.
TRFL of an Extremely
The only requirement on the signal source is that it have an auxiliary output. The awilliary output is down-converted and substitutes as the
(LO) for the HP 8902A. With this setup, the same residual
FM,
drift,
or instablilty present at the signal source output input to the is also present
HT
890214. This enables the IF Synchronous detector in the HP 8902A to automatically track the noisy input signal.
Harmonic Mixing
In normal operation, the HP 8902A its internal local oscillator (LO) harmonic mixing of the internal to make measurements to
You can extend the measurement range to 2.1 produces higher conversion loss, measurement sensitivity degrade above 1300
LO. of three techniques available for extending the RF frequency range of the HP
MHz to
8902A. The other
-105 dBm at 2.1 two uses the fundamental mixing of
GHz by using
(Because harmonic
GHz.)
1300 mixing
MHz. begins to
This is one are also shown in this chapter.
1. Connect the
HP
8902A to the signal source and set the source level to between 0 and -20 dBm. Disregard Error 10 if it is displayed.
2.
3.
4.
Press
TUNED RF
Shift
LEVEL key, the key.
INSTR PRESET key, the gold S key, and the
Key in 3.6 SPCL to select the narrow-band 455 kHz filter.
Press the Blue Shift key and the DISABLE ERROR (RANGE
HOLD) key to disable Error 01 if it remains in the display.
5.
6.
Manually tune the less than one third to tune to a 2100
HP
MHz
699.6867 MHz: (2100/3)
8902A signal
- to a frequency equal to to be measured. (For example, manually tune the HP 8902A to
0.30333 MWZ =
0.30333
699.6967
MHz
MHz.)
Decrease the level of the input signal and perform the TRFL calibration.
Press the LOG/LIN key if you wish to toggle between Watts and dBm units.
Installation
Unpack Your
Inspect the shipping container for damage. If the shipping container is damaged or the cushioning material inside is stressed, keep them until you have checked the shipment for completeness and proper operation.
If components are missing from your shipment, or if there is mechanical damage or defect, notify the nearest Hewlett-Packard office. If the shipping container or cushioning material shows signs of stress, notify the carrier as well as the Hewlett-Packard office. Keep the shipping materials for inspection by the carrier.
Connect Power
If you are not sure of the power or fuse requirements for your instrument, refer to Section 2 of the HP further information.
8902A Operation and Calibration Manual for
Connect the
Connect the Sensor Module to the SENSOR and INPUT ports. (Refer to
Appendix B in this guide for information on configuring the HP 8902A to operate with your Sensor Module.)
Turn On
Instrument
If you are operating this instrument in extreme environmental conditions, refer to Section 2 of the HP 8902A Operation and Calibration Manual for specific operating limitations.
Calibration Factors
What to Do
The calibration data for the Sensor Module you are using must be entered into the HP 8902A before it can make calibrated RF Power measurements.
To determine the appropriate action to take, find the description below that best describes your circumstances and take the action recommended.
Descriptions
If your HP 8902A and Sensor Module were ordered together as an Option
021, E02, E04, or as part of a system, the calibration factors for the
Sensor Module have already been entered into the HP return to Chapter 2
8902A. (You can to begin making measurements with the HP 8902A.)
If the HP 8902A displays Error 15 when you press the RF Power key, no cal factors have been entered. Perform the Entry Procedure now.
If you are changing sensor modules or if the cal factors for your Sensor
Module have changed (due to repair or calibration), perform the Entry
Procedure to enter the new cal factors.
Not Certain if Correct
Cal Factors Entered
If you are not certain that the cal factors in the HP 8902A match the cal factors of the Sensor Module you are using, perform the Verification
Procedure provided in this section. If the cal factors in the instrument do not match those listed on the label of your Sensor Module, perform the
Procedure.
Entry
If you are entering calibration data for a microwave Sensor Module, such as the HP 11792A, key in
Mode and then perform the
27.1
Entry
SPCL to enter the Frequency Offset
Procedure. (When you get to step 7, enter the calibration data directly from the Sensor Module’s label.)
5 2 Appendix B Calibration Factors
Entry Procedure
1. Find the Reference Calibration Factor on the label of your Sensor
Module of this
(REF procedure.
Record that value in the space provided in step 6
2.
3.
Find the Calibration Factors listed on the Sensor Module label (CAL
FACTOR %). Record each value in the appropriate space provided in step 7 of
this
procedure.
Connect the Sensor Module to your key and of the then
HP
the
890%. green
8902A and press the
AUTOMATIC OPERATION
Blue Shift key on the front panel
4. Key in 37.9 key, lower right corner). This clears the HP 8902As cal factor
SPCL storage
(press the 37.9 digit keys and then the SPCL table in case it contained any incorrect data.
5. Press the RF POWER key. The instrument will display Error
15. (Error 15 will go away once the calibration data is entered.)
Enter Reference
Cal Factor
6. Key in key.
37.3 SPCL,
Remember
, Blue Shift key, and then the MHr
Press the CLEAR
key
if you mishy a digit. If you suspect that you have entered wrong data, complete the Entry Procedure and then perform the Verification Procedure to check the stored data. The Error
Correction Procedures will enable you to change any incorrect data.
Pairs
7. Enter
Entry Code, Frequency, then Cal using the key sequence
Factor%)
shown in the table below. Repeat the procedure for each frequency/& factor pair listed. a a
.l
3 f
3
10
30
MHz
MHt e e e e e e e
8. Press the green AUTOMATIC OPERATION key to reset the instrument to normal operation. You have completed the cal factor
Entry Procedure. The following VeriFcafion Procedure will enable you to venfy that the data in the cal factor storage table is correct. e
0
Appendix 6 Calibration Factors 5 3
Verifica fion
Procedure
1. Press the green AUTOMATIC OPERATION key and then the
RF POWER key. If the HP 8902A displays Error 15, there is no calibration data stored in the instrument; perform the Enfry Procedure.
2. Key in 37.5 SPCL, the Blue Shift key, and then the MHr key. If the displayed Reference Cal Factor does not match the Reference Cal Factor
(REF CAL FAC) on your sensor module, perform step 1 and step 6 in the
Entry Procedure.
3. Repeat the key than once, enter sequence shown below to display each frequency and Cal Factor stored the
HP
8902A’s
Check each frequency and cal factor sensor module. (If you want to review the non-volatile memory. pair against those listed on your cal factor storage table more
37.5 SPCL to return to the beginning of the table.)
4. Press to normal operation.
You the will green
You have completed the verification procedures. not need to repeat the
Entry
key to reset the instrument
Procedure again unless you use the HP 8902A with another Sensor Module or change the cal factors for this Sensor Module (due to repair or recalibration).
Procedures
Ca/ kctor
0
If the frequency is correct but the cal factor in the Enfy Procedure factor only. (The HP for that frequency and enter its correct cal
8902A will is not, perform step 7 place the new entry in the correct position in the table and remove the incorrect cal factor.) (Fur example, if an incorrect cal factor value was entered for 10 you would correct it by entering 37.3 SPCL, 10 MHz, the correct cal factor value, Blue Shift key, MHz.
MHz
The HP 8902A automatically positions the new cal factor in the 10 MHZ position in the table.)
Frequency
0
If an incorrect frequency is stored in the table, remove the incorrect frequency by performing step 7 of the entry procedure using the incorrect frequency and entering 0 as the cal factor.
Both
0
If you need to add both a frequency and its cal factor to the storage table, perform the entry procedure (step 7) for the correct frequency and cal factor.
(The HP 8902A will place the new entry in the correct position in the table.)
c
Index
A
C
Calibration,
Calibration Factors, B-1
F
(See also RF Frequency),
H
Dashes, 1-4 two, 1-4 four, 1-4
Detectors,
Drift,
RF Frequency Measurements, 2-7
Modulation and Audio Measurements, 3-6
E
RF Frequency and Frequency Error, 2-10
M
MODULATION OUTPUT/AUDIO INPUT, 1-11,
Noise,
RF Frequency Measurements, 2-6
Modulation and Audio Measurements, 3-6
0
Phase Modulation, 1-13
Power (See RF Power),
R
Relative TRFL Measurements, 4-5
calibration factors, B-1
Selectivity,
RF Frequency Measurements, 2-5
Modulation and Audio Measurements, 3-5
RF Frequency Measurements, 2-7
Modulation and Audio Measurements, 3-7
Sensor Module, 8-1
microwave, B-1
Special Functions, 1-26 special display, 1-26
T
calibration, 1-21, 4-3 detectors, 4-3
U
z
D
Other Publications
Precision Measuring Receiver,
(Data Sheet) November 1985
5953-8437 Spokane Di3ision
HP 8902A Measuring Receiver,
(Flyer) March 1983
5953-8380
Accurate Characteristics at Millimeter- Wave Frequencies
(Product Note) November 1985
5953-8436
,
HP 8902A Measuring Receiver Operation and Calibration Manual,
December 1985
08902-90029
HP 8902A Measuring Receiver Service Manual,
08902-90031
HP 89028 Microwave Measurement System Manual,
December 1985
08902-90046
HP 8902A Microwave Signal Generator Calibration System
Option E04 Manual,
08902-90048
HP 7 7 722A Sensor Module Operating and Service Manual,
11722-90009
HP 7 7 792A Sensor Module Operating and Service Manual,
March 1983
11792-90008
For information about Hewlett-Packard products and services, telephone the local Hewlett-Packard sales and support office listed in your telephone directory.
Or write to the appropriate address listed here.
United States
Hewlett-Packard Company
Microwave and
Communications Group
3000 Hanover Street
Palo Alto, CA 94304
Hewlett-Packard Company
4 Choke Cherry Road
Rockville, MD 20850
Hewlett-Packard Company
5201 Tollview Drive
Rolling Meadows, IL 60008
Hewlett-Packard Company
5161 tankershim Blvd.
North Hollywood, CA 91601
Hewlett-Packard Company
2000 South Park Place
Atlanta, GA 30339
Canada
Hewlett-Packard (Canada) Ltd.
6877 Goreway Drive
Mississauga, Ontario
Canada, L4VlM8
Europe and Africa
Hewlett-Packard S.A.
P.O. Box 529
1180 AM Amstelveen
The Netherlands
Australasia
Hewlett-Packard Australia Ltd.
3 1-4 1 Joseph Street
Blackbum, Victoria 3130
Australia
Japan
Ltd.
29-21, Takido-Higashi, 3-Chome
Suginami-ku, Tokyo 168
Japan
Far East Area
Hewlett-Packard Asia Headquarters
47th F, China Resources Bldg.
26 Harbour Road, Wanchai
Hong Kong
Latin America
Hewlett-Packard Company
3495 Deer Creek Road
Palo Alto, CA 94304 U.S.A.
Printed in USA
08902-90049
6/86
Model 8902A Operation
LOCAL OPERATION
This space is provided for you to store the HP Y902A Basic Opunlion and Applicalion Giiide (HP part number
This guide contains all basic information about the local and remote operation
Receiver. of the Measuring
If you have not yet operated the Measuring Receiver, you should use this document to become familiar with basic operation
Measuring Receiver, you may want to of the instrument. After you learn basic operation put that supplement here for easy reference. of the
(Put this page behind the “Local” tab in the Operalion aiid
Calihrarion Maniral.)
Model 8902A
Operation
Remote Section Contents
0
0
0
0
0
0
0
0
0
0
0
0
THE HEWLETT PACKARD INTERFACE BUS (HP-IB)
...........................................................................
MEASURING RECEIVER REMOTE CAPABILITIES (IEEE.488)
0
0
0
0
0
0
0
..................................................
.................................................................................
Code String Syntax (Sequence Dependency)
.................................................................................
.............................................................................
0
0
0
How to Use this Section to Make a Measurement
.............................................................................................
.....................................................................................
.......................................
.................................................................................................
..........................................................................
Reading the HP-IB Address Switch and
TALK and LISTEN Status Descriptions
Code Execution in the Measuring Receiver
.................................................
..........................................................
3-1 1
Model 8902A Operation
3-6. REMOTE OPERATION VIA THE HEWLETT PACKARD INTERFACE BUS (HP-18)
Introduction to the Section
This section documents how the instrument interacts with a controller over HP-IB in remote operation. This section is intended as a reference document for operators who are familiar with their controller protocol and programming language, and been introduced to is designed basic front-panel and remote operation by the to be used after you have
HP 8902A Basic Optwtion and
Application Giridc. (HP part number 08902-90049) which is included with this documentation package.
Accurate measurements are dependent on the proper functioning of the both the
Measuring Receiver. The
Checks of
Basic Fiinctional Checks of the Mcasiiring Rtwivcr and the Basic Fitnc/ional
(he Hewlt>ft Packard intt>flact' are operating properly and can respond to
(HP-iB) or
HP-IB and the verify that the Measuring Receiver and send bus messages.
HP-IB
How
to Use this Section
to
Make a Measurement
Beginning Users: You will need to read the and perform the procedures described there instrument. Then read the portions of the to
HP 8902A Basic Operation and Application Giiide become familiar with the basic operation of the
Detailed Operating Instriictions (in this manual) describing the measurement you want to make. Then return to this section and read "Programming the
Measuring Receiver", paragraph 3-7. This information should be enough most measurements. to enable you to make
Intermediate Users: If you are familiar enough with programming the instrument to feel you can skip the above steps, you may be interested in more specific information. In this case read the paragraphs titled, "Data Output", "Hewlett Packard lnterface Bus", "Measuring Receiver Remote
Capabilities", and/or "Additional Information" as appropriate to your needs.
Advanced Users: You may be able to program the instrument just using the tables in the back of this section which list the codes required to make measurements, the modifiers for each measurement, and other related information. Specific subjects such as Triggering, the Service Request Message and the Status Byte may be of interest. Explanations can be found in paragraphs of the same name.
3-7.
PROGRAMMING THE MEASURING RECEIVER
Overview
All Measuring Receiver functions are fully programmable, except the POWER switch.
The Measuring Receiver can be externally triggered (Refer to "Triggering Measurements", under paragraph 3-10.) Triggering can be used to allow the Measuring Receiver to a measurement. It can be used to control when the Measuring Receiver takes outputs the result. settle before making a measurement and
Valid Programming Codes
The HP 8902A will execute:
0
The function codes described in Table 3-1
I, "Measuring Receiver Function to Code Summary"
0
Valid special functions (refer to page 3-275 for a list of special functions). All special function
codes are formed by the special function number followed by the code "SP"
0
The HP-IB commands described in Table 3-7,
"Measuring Receiver Remote Capabilities
Table".
3-13
Operation Model 8902A
As a convenience, all lower case alpha characters are treated as upper case. Commas and spaces between program codes are ignored by the instrument and therefore may be used readability in programming. to improve
Measurement Codes All front-panel keys except the LOCAL key have corresponding instrument- dependent program codes. These codes consist of either two alphabetic characters, character and a number; e.g.,
- or
M3. list of programming codes required or an alphabetic
The underlined letters on the front-panel key labels are both
AUTOMATIC OPERATION is AU, and the codes for TRACE MODE are to make measurements with the
functions) are contained in Tables 3-1 1
and 3-12.
HP
K1 and KO. The entire
(not incliiding special
Turning Off Functions When operating in local operation, many of the functions toggle on and with successive keystrokes.
Codes turning
In remote operation, a specific code turns
these functions are given in Table 3-1,
"Turning Off Functions". off
HP-IB
Tahk 3-1. Turning Oif Functions
Functions Off
Audio Input Off (Mod. Output On)
Calibrate Off
Disable Error Function Off
Range Hold Off (Auto Range On)
All HP Filters Off
Track Mode Off (Lock Mode On)
All LP Filters Off dB Ext. Attenuator Off
Pre-display and De-emphasis Off
Ratio Off
KO
LO
NO
PO
Code
A0 co
BO
GO
HO
RO
Invalid Characters
The following Table 3-2, "Response to Unused ASCII Characters" lists the Measuring Receiver's response to various ASCII characters not used in its code set. The characters in the left-hand column are ignored unless they appear between two characters of a program code (e.g. the characters of a function code); in which case, they generate Error 24. The characters in the right- hand columns, if received by the h4easuring Receiver, will always cause and a Service Request message to be generated.
Error 24
M 3, space between
(invalid HP-IB code)
3-14
Model 8902A Operation
Ignored *
!
#
O/O
Generates Error 24
@
J
Q
1
Y
DEL
I
'ExceDt when inserted between two characters of a Drwram code.
I
Programming
Syntax
Function Code Syntax The function code syntax is typically equivalent to the front-panel keystroke sequence used in local operation. (Refer to Basic Operalion and Application Gitidc.
Optv-ating Instrrtctions for keystroke sequences.) or the Dvlailed
There are three different syntax which execute functions. Refer to Table
Examples" for examples.
3-3, "Function Code Syntax
1) Using a two character code or suffix alone, which is the common case.
2) Using a number and a suffix.
3) Using a prefix (usually a special function), a number and a suffix.
Code
MZ
100 MZ
27.3SP 100 MZ
CF
98 CF
37.3SP 98 CF
Operation Performed
Center I.F. Frequency
Tune to 100 MHz
Enter and enable external L.O. frequency of 100 MHz
Read current Calibration Factor
Enter a Calibration Factor of 98%
Enter an automatic RF Power calibration factor of 98%
3-15
Operation Model 8902A
3-16
Number Entered in Code
,1234567899999
1234567890
Number Accepted by Instrument
0.1234567
12345678 E02
Code String Syntax (Sequence Dependency)
For accurate measurement results, functions should be programmed in the following order to insure proper sequencing of events and switching in the instrument as appropriate to the measurement.
The letter X in the following example represents a number.
Function codes that have the same alpha-character should be entered in numeric order to ensure proper execution; e.g., P1 should come before P4.
Mode of
Tuning
Operation
Input Freq Units (Manual Tuning)
Measurement
Detector
De-emphasis
Filters
Special Functions
Ratio
Trigger
OUTPUT714;" AU XXX.XX MZ M X DX PX HXLX XX.XSP RX TX"
T T ~ ~ ~ i ~ ~ b
+
The following information should be considered in addition to the information above when writing programming strings.
~1
0
AU (Automatic Operation). When Automatic Operation is used, it should appear at the beginning of a program string. Automatic Operation sets all special fiinctions prefixed 1 through
10 to their zero-suffix mode. Most other special functions are also set to zero-suffix.
PO (Pre-Display Off and De-Emphasis off.
Off). When pre-display is turned off using PO, all FM
Model 8902A Operation
Pre-Display selected. In (his case, FM Dtwmphasis will be tiirned be Icfl
is
no1 tiirned of if on. Prtvhplay is rcqiiircd
NOTE the Audio
by thc A
RMS Detector iidio RMS
(OS)
ofl
birt is
on
when PO
Pre-display is
0
T2 and T3 (Trigger Immediate and Trigger With Settling). Trigger codes should always appear at the end of a program string, and the triggered measurement results must be read before any additional program codes are sent the trigger codes T2 immediately initiated. or T3 to ensure an accurate measurement. When either of
Programming Examples
Code String Example Function codes may be sent to the instrument in a continuous string as shown below. The code string shown will program the instrument to determine the positive peak de-emphasized (75 ps) FM deviation of an input signal at 104.5 MHz. The measurement is triggered with T3, Trigger with Settling.
OUTPUT714;" AU 104.5 MZ M2 D1 P1 P4
I
Automatic Operation
Frequency (Manual Tuning)
Units
FM
Peak+ Detector
1
FM De-emphasis and Pre-display
75 ps FM De-emphasis
Trigger w/Settling
Example Measurement Program The following example provides you with a sample of how the previous information might be used to program the HP 8902A
This example demonstrates measuring AM in the using Trigger Hold and Trigger with Settling.
50 Hz to 15 to
KHz make a particular measurement. bandwidth of a 100 MHz carrier
10 OUTPUT 714; "IP"
20 OUTPUT 714; "M1 100 MZ H1 L2 T1"
30 OUTPUT 714; "T3"
40 ENTER 714;A
50 PRINT A
60 END
Instrument Preset to configure instrument to a known state.
Send code to configure instrument for measurement.
Trigger settled measurement.
Read data into variable A.
Print variable A
Reference Tables
Table 3-1 1, "Measuring Receiver Function to Code Summary"
This table lists the instrument- specific fLinction code for each Measuring Receiver function described in the Detailed Operating
Inslriictions of this manual.
Table 3-12, "Code to Measuring Receiver Function Summary" This table has the same information
as Table 3- I I, "Measuring Receiver Function to Code" but is organized alpha-numerically by code.
3-17
Operation
NOTE
The following tables are intended as a rtj2riwce for advanced itsm who arc familiar with the HP 8902A meastrrement capabilities.
Model 8902A
"Measurement Modes and Codes" All of the functions listed on this table are defined as "measurement modes" in the instrument. The instrument can only be in one Measurement Mode at a time. If a measurement mode is volatile, pushing the CLEAR key will return the instrument to or entering the last selected, non-volatile measurement mode,
CL over the bus,
This table lists all the measurement modes of the programming codes. This table also lists whether or not the measurement mode is volatile, whether the receiver section of the HP
HP 8902A Measuring Receiver and their
8902A is used to make the measurement, and whether the
Demodulation Output is blanked during the measurement.
4, "Measurement Modifiers" Whenever a measurement is selected, the Measuring
Receiver sets up its internal circuitry so it can make the most accurate measurement possible. These settings can be altered by the operator to modify the measurement.
This table lists the measurement modifiers for the primary measurement modes listed in Table
"Measurement Modes and Codes".
3-13,
To see what modifiers are being automatically selected,
0 use the Special Special display to read the Range in use,
0
0 read the front-panel lights for the Detectors, Filters and De-Emphasis in use and see Table 3-15 or -16, "Enabling/Disabling Variable Parameters (Front Panel
Attenuation, the Limits set, and whether Ratio has been selected. or Remote)" for a summary of how to read the Calibration Factors, the Frequency Offset, the dB external
Table 3-1 5, "Enabling/Disabling Variable Parameters (Front Panel)"
This table lists ways of verifying from the front panel the values of the Calibration Factors, Frequency Offset,
Attenuator, Limit/Ratio and Set Reference functions. dB External
6, "Enabling/Disabling Variable Parameters (Remote)" This table is the same as Table
3-15 except that it shows the programming codes required instead of the front-panel keystrokes.
7, "HP 890lA/02A Code Differences" This table lists the function code differences for identical fiinctions of the HP 8902A and the HP 8901A, and should be usefitl in modifying existing
HP 8901A control programs to drive an HP 8902A.
3-8.
DATA OUTPUT
Data Output Format
Numeric Data constant. Data
As shown below, the output data is always in the form is always output in fiindamental units (for example, Hz, Yo, etc.), and the decimal point (not sent) is assumed to be to the right of the tenth digit of the mantissa.
Data values never exceed +9 000 000
Output data is displayed using the following format: first the sign, then 10 digits (leading zeros not suppressed) followed by the letter E and a signed two-digit exponent. The last two characters string are a carriage return (CR) and a line feed
"Data Output Examples" for examples.
(LF) of the
in string positions 16 and 17. Refer to Table
3-18
Model 8902A Operation
Table 3-5. Oiitpiil Examples instrument Display
969.21346 MHz
34.92 kHz
Data Output
+0096921346E+01
+0000003492E+01
<CR><LF>
<CR><LF>
*
Error Messages Error message format and syntax are described in the
Error Mtmages Sirmmary
3-9. HP-16 INFORMATION
HP-IB
Capabilities
The interface functions that the HP 8902A
implements are defined in Table
488 Interface Function Capabilities". The Measuring Receiver's compatible with the IEEE Standard 488, and the identical ANSI
HP-IB
Standard MC1.l.
"IEEE Std command capabilities are
For more information about the Hewlett-Packard Interface BUS to:
0
IEEE Standard 488,
0
ANSI Standard MC I. 1,
0 the Hewlett-Packard Electronic Systems and Instruments catalog,
0 the booklets, "Improving Measurements in Engineering and Manufacturing" (HP part number
5952-0058), and "Tutorial Description of HP-IB" (HP part number 5952-0 156).
Table 3-6. 488 Interface Firnclion Caoahililies Table
Bus Command
Source Handshake
Acceptor Handshake
Talker Function
Extended Talker
Listener Function
Extended Listener
Service Request
Remote Local
Parallel Poll
Device Clear
Device Trigger
Controller
Driver Electronics
Capability
SHI Complete Capability
AH1 Complete Capability
T5 Complete Capability including Talk Only *
TEO No Capability
L3 Complete Capability including Listen Only mode
LEO No Capability
SR1 Complete Capability
RL1 Complete Capability
PPO No Capability
DCI Complete Capability
DT1 Complete Capability
GO No Capability
El Open Collector Drivers
* Instrument also has a Talk Status Only mode
3-1 9
Operation Model 8902A
HP-I6
Address
Factory Set Address
The Measuring Receiver's HP-IB address is set to decimal 14 at the factory with Talk Only and
Listen Only modes disabled. The address can be changed by following the instructions in paragraph
2-3
Reading the Address
To display the HP-IB address in decimal on the front panel, select BUS ADRS by pressing the Blue key and then the LOCAL key. The displayed address is in the form:
Addr=NN
Where NN is the two-digit address in decimal. The display will time out after a few seconds.
Refer to "Additional Information", paragraph 3-1 1 for more information about HP-IB address.
3-20
Model 8902A Operation
3-10.
MEASURING RECEIVER REMOTE CAPABILITIES (IEEE-488)
The capabilities of the HP 8902A in remote operation and their related IEEE Std 488 terms are
described in Table 3-7, "Measuring Receiver Remote Capabilities Table". The twelve capabilities
described there are further described in the paragraphs following the table.
Capability
Data
Trigger
Clear
Remote
Local
Local Lockout
Clear Lockout/
Set Local
Yes
Yes
Yes
Yes
Yes
Tahk 3- 7. Mtwwring Rtwivcjr Remoie Capahiliiies (1 o
Enabled
Yes
Measuring Receiver Capabilities
Response
All front-panel functions, special functions, and remote-only functions are programmable, except the POWER switch. The
Measuring Receiver can send the Status Byte, and message and setting information. All measurement results, special displays, and error outputs (except dashed displays) are available via the bus.
MLA
MTA
IEEE Stc
Commands and Control
Lines
I88 '
Interface
Functions
AH1
SH1
T5
L3
Yes DTl If in remote and addressed to listen, the Measuring Receiver makes a settled measurement. It responds equally to bus command GET and program code T3, Trigger with Settling.
GET
Clears Status Byte, issued), and sets the
RQS
SRQ bit, Service Request message (if
Mask to the 22.0SP equally to DCL and SDC bus commands. Resets many additional parameters as shown in Table 3-8, "Response to a Clear
Message."
DCL
SDC
The Measuring Receiver's remote mode is enabled when the
REN bus line is true. However, it remains in local (Le., the front panel is active) until it is first addressed to listen. The output signal and internal settings are unchanged when the Measuring
Receiver enters remote mode. All front-panel keys are disabled except LOCAL and CLEAR, unless the instrument is in Local
Lockout.
REN
M LA
The Measuring Receiver returns to front-panel control when it receives the Local message. No instrument settings or functions are changed except Trigger is set to Free-Run (TO). Responds ei- ther to the GTL command or the keyboard Local key. The LOCAL key will not work if the instrument is in LOCAL LOCKOUT.
GTL
All front-panel keys including the LOCAL and CLEAR keys are disabled during Local Lockout so that only the controller or the
POWER switch can return the instrument to Local.
LLO
The Measuring Receiver returns to Local and Local Lockout no longer true when the REN bus lines go false. is
REN
DC1
RL1
R L1
RL1
RLl
* Commands, Control Lines, and Interface Functions are defined in IEEE Std 488 (and the identical ANSI Standard MC1.l). F )wledge of these might not be necessary if your controller describes its capabilities in terms of the HP-IB capabilities shown in the left column.
3-2 1
Operation Model 8902A
Capability
Pass Controll
Take Control
Service Request
Enabled
No
Table 3- 7. Measiiring Receiver Remote Capuhilifies (2 of 2)
Measurina Receiver Capabilities
Response
The Measuring Receiver cannot pass or take control of HP-IB.
~ ~~
IEEE Std 488=
Commands and Control
Lines
Interface
Functions co
Yes SR1 The Measuring Receiver sets the SRQ bus line true if any of the conditions defined in the Status Byte occurs and has been enabled by the SRQ Mask (Special Function 22) to send the
Service Request message.
SRQ
Status Byte Yes The Measuring Receiver responds to a Serial Poll Enable (SPE) bus command by sending an 8-bit byte when addressed to talk.
Bit 6 is true if the instrument has sent the Service Request
Message.
SPE
SPD
MTA
T6
Status Bit
Abort
No
Yes
The Measuring Receiver does not respond to a parallel poll.
The Measuring Receiver stops talking or listening. IFC
PPO
T6
L3
* Cornmancis, Cor ,I Lines, and Interface Functlons are deflned In IEEE Std 488 (and the identical ANSI Standard MC1.l). Knowledge of these might not be necessary If your controller describes Its capabilities in terms of the HP-IB capabliitles shown In the left column.
Triggering Measurements
In remote operation, two triggering modes are available: Free-run and Trigger Hold. In Free-run mode, measurements are continually, automatically taken. In Trigger Hold mode, the instrument sets up for the measurement and then waits for a trigger to be received. Valid triggers to use in
Trigger Hold are: T2, T3, GET or the CLEAR key.
The instrument goes into Trigger Hold mode after it receives a trigger (except the if it was in Free-run before it received the trigger.
CLEAR key) even
TRIGGER MODES (TO and T1)
Free Run Mode (TO) This trigger mode is in effect in local operation, and is also in effect in remote when Trigger Hold mode has not been selected. Measurements are made and measurement data updated as rapidly as settings can be changed without regard for settling of ANY internal or external circuitry or setting changes.
3-22
Model 8902A Operation
Trigger Hold Mode (Tl) In Trigger Hold mode, internal settings can be changed by the instrument itself or by the user via the bus; however, the instrument is inhibited from outputting any data to the front-panel key lights and display, or to the HP-IB until it receives a trigger. The following data can be sent before the trigger is received:
0
A Service Request message if an enabled LIMIT is reached, or if an HP-IB code error occurs.
0
The Status Byte if the instrument is serial polled. (A serial poll, however, will trigger a new measurement, update displays and return the instrument to Trigger Hold.)
Measurement data is replaced with data acquired from subsequent triggered measurement cycles.
NOTE
When a trigger is rC.c.civcd, fhr Mcawring Rcwivcr will not allow its
mcasirrcmenr cyck lo hc infcrrirpk>d. (Indccjd, handshakc of hiis commands is inhihiled irnlil lhc mc’t2sirrtvnenl cycle iJ cornplclle)
Entering Trigger Hold The instrument is placed in this mode after it receives the programming code T I or after a triggered measurement has been executed. This mode can then be used to set up the instrument for new measurements which are executed by a trigger.
Triggering Measurements from Trigger Hold When a measurement is triggered from Trigger
Hold mode, the instrument makes the measurement. The display is updated as the new measurement cycle begins. The Status Byte will be updated (and the Service Request message issued if required) by the events that occur during the new measurement cycle.
Any of the following events will trigger
Trigger Hold: a new measurement cycle when the instrument is in a. instrument receives a trigger, b. instrument receives its listen address, c. instrument receives GTL (Go To Local),
After the measurement is made, the instrument waits for the measurement results to be read.
While waiting, the instrument can process most bus commands without losing the measurement results. Once the data (measurement results) are read onto the bus, the Measuring Receiver returns to the Trigger Hold mode.
Leaving Trigger
Hold
The instrument leaves Trigger Hold mode when it receives a trigger until the measurement is complete. The Measuring Receiver also leaves Trigger Hold when it receives: a. the Free Run code (TO), or b. when it is returned to local operation, c. a Device Clear Message (DCL or SDC), or d. Instrument Preset (IP).
TRIGGERS (T2, T3, GET,
and
the CLEAR Key)
All triggers are available in both Free Run and Trigger Hold modes, but after a trigger is received
(except the CLEAR key), the instriiment enters Trigger Hold mode.
Trigger Immediate (T2) When the Measuring Receiver receives the Trigger Immediate code, it makes one measurement and displays the result without a settling time delay.
Measurement results obtained via Trigger Immediate are normally valid only when the instrument is in a steady, settled state. The first result received fiom the instrument (using T2) may not be accurate.
3-23
Operation Model 8902A
Trigger With Settling (T3)
NOTE
0
Thc iise of Trigger With Settling docs the normal warm-up precairfions when iising either the RF Power, AM, or FM Calibrator. Refir
Instructions
not
remove the need to the procediires
"RF
to observe
Power Calibration",
"AM Calibration", or "FM Calibration" in the Detailed Operating
0
If the settling time povidcd with T3 is not adequate rnc>ascrrernents, compares measirrement valiies iinfil they are within
(Delays, not inclirded in the T3 settling time. in the soiirce and/or the thermocoi~ple in use the to
a
prodiice accirrate specijed tolerance.
Power Sensor can prevent acciirafe measirremenfs.)
Trigger With Settling is identical to Trigger Immediate except the Measuring Receiver inserts a settling-time delay before taking the requested measurement.
Group Execute Trigger (GET) Message When in remote and addressed to listen, the Measuring
Receiver responds to a Trigger message (GET) by executing a settled-measurement
Measuring Receiver responds exactly as if it had received the program
Settling). code T3 cycle. The
(Trigger With
Triggering Measurements With the CLEAR Key (CL) When the Measuring Receiver
Hold mode (TI) and not in Local Lockout, the front-panel CLEAR key may be used to issue a
Trigger With Settling. Each time the CLEAR key is pressed, the Measuring Receiver performs a settled-measurement cycle. The CLEAR key will not cause the instrument mode. to is in Trigger enter Trigger Hold
In Free Run mode the CLEAR key will clear the display, but not affect the timing of measurements and will not cause the instrument to enter Trigger Hold.
NOTE
The CLEAR key message (DCL or
(CL)
SDC). does not ptvjbrm any of' the
fiinctions
of the Clear
3-24
Model 8902A Operation
Clear
The Measuring Receiver responds to the Clear message (DCL and SDC) the same way it responds to Instrument Preset (IP). The Clear message clears any pending Service Request message and clears the SRQ Mask (22.0SP). The settings the instrument will assume after receiving the Clear message
3-8. Refer to "Instrument Preset" in Dctaikd Operating
3-239 for more information on the Instrument Preset default conditions.
Instrirctions on page
The Clear message also clears any incomplete message or entries.
Frequency Measurement, been entered.
For example, "M5100" (RF
100, no terminator) would be cleared because no units terminator has
Parameter
High-Pass Filters
Low-Pass Filters
FM De-emphasis
Pre-display
Calibration
Measurement
Detectors
Ratio
Limit
Lower Limit Reference
Upper Limit Reference
Limit Measurement Mode
Automatic Operation
Manual Operation
SPCL
MHz Input Frequency
9
and l,l Step Size
Modulation Output
Service Request Mask
Status Byte
Trigger Mode
Setting
All Off
All Off
Off
Off
Off
Frequency
Peak
+
Off
Not Enabled
150 kHz
1300 MHz
Frequency
On
Automatic Tuning
0 kHz
Special Functions prefixed 1 through 10 in zero- suffix mode; all others off
FM (least sensitive range)
HP-I6 code error enabled only (22.2SP)
Cleared
Free-run (TO) or after power-up, the Measuring Receiver will tune to 100 MHz.
3-25
Operation Model 8902A
Remote/Loca I
Mode Descriptions
Remote Mode In remote, the Measuring Receiver’s front-panel controls are disabled except for the LOCAL and CLEAR keys. The LOCAL and CLEAR keys are only disabled by Local Lockout.
However, front-panel displays and the output signal at MODULATION OUTPUT/AUDIO INPUT remain active and valid. Two triggering modes are available in remote operation: Free Run and
Trigger Hold.
Displays which time out in Local do not time out in Remote. In Remote operation, the CLEAR key will clear the display and works as a trigger when Trigger Hold is used.
Local Mode In local, the Measuring Receiver’s front-panel controls are fully operational. When the Measuring Receiver goes to local operation, the front-panel REMOTE annunciator turns off,
However, when the Measuring Receiver is being addressed (whether in remote panel LISTEN operation. or or local), its front-
TALK annunciator lights. Free Run is the only triggering mode available in local
Mode Transitions
Local to Remote Transitions of the Remote message. No
The Measuring Receiver switches to remote operation upon receipt instrument settings are changed by the transition from local to remote.
The Trigger mode will always be Free Run (TO) on entry to remote operation.
Remote to Local Transitions The Measuring Receiver always switches to local from remote whenever it receives the Local or the Clear Lockout/Set Local message. No instrument settings are changed by the transition from remote to local, except the Trigger mode will always be reset
Free Run. to
If it is not in Local Lockout mode, the Measuring Receiver switches to local from remote whenever its front-panel LOCAL key is pressed.
NOTE
Remote to Local transitions will not slrtrr
a
Stv-vict.
Rcqiit>.Tf mtwage.
Local Lockout
Local lockout disables the LOCAL key (and the CLEAR key) and allows return-to-local only under program control.
When a data transmission is interrupted, which can happen if the LOCAL key is pressed, the data being transmitted may be lost. This would leave the Measuring Receiver in an unknown state. To prevent this, a local lockout is recommended.
3-26
Model 8902A Opera tion
Clear Lockout/Set Local
The Measuring Receiver returns to local operation when it receives the Clear Lockout/Set Local message.
NOTE
CIsav
Lockoirt/Sct
disadvan t agtx
Local can bc accomplished by switching lhc power 10 STBY and hack to ON. Rvlitrning lo Local optv-alion in lhis way has lhr following
0 e
II defiats [he pitrpose of Local Lockoitt (rhal is, the syslcm controller will
lose
conlrol of /he Measiiring Receiver). instrirment configitration is rtwt to Powcr-iip conditions listed in the
Detailed Operating Instructions
3-23 9. itndcr tYn.striimcnf Prtwt" on page
Service Request Message
(SRQ)
The Service Request Message (SRQ message) is being issued when the SRQ under following conditions: bus line is asserted and the SRQ light on the front panel is lit by the instrument. The Service Request message may be issued
0 the instrument requires re-calibration or is uncalibrated,
0 there has been a Frequency Offset mode change,
0 an enabled limit has been exceeded,
0 an instrument error has occurred,
0 an HP-IB code error has occurred, e measurement data is ready to be read.
The Measuring Receiver uses it.s Status Byte and the SRQ Mask (Special Function 22) to determine whether or not to issue a SRQ message. Refer to Figure 3-4, "Issuing a Service Request Message" throughout the following discussion of the Service Request Message, SRQ Mask and the Status Byte.
The Service Request Message is asserted when the RQS bit of the Status Byte is set by the instrument.
The RQS bit is set automatically when one or more of the other bits in the Status Byte are set. For the bits other than the RQS bit of the Status Byte to be set, those bits must be enabled by the SRQ
Mask before the instrument condition which will set them occurs.
The instrument can send the Service Request message in either local or remote operation.
Clearing the Service Request Message After the Service Request message has been sent, it will be cleared when the Status Byte is cleared which is described below under 5tatus Byte".
3-27
3-28
Operation Model 8902A
START 8902A 1
1
1
L
TEST OTHER 8902A
SRO CONDITIONS
READY
1
TRIGGER MEASUREMENT
CLEAR KEY)
1
1
FROM 8902A
RETURN FROM INTERRUPT
Figiirc 3-3. Exampkc Flowchart
Using
the Scv-vicv Rqiwst Mcwagc..
Using the Service Request Message The Service Request message can be used for detecting instrument conditions and instrument or HP-IB code errors.
The Service Request Message can also be used for signaling measurement data ready. Remote measurements are usually performed simply by triggering measurements, then reading the oiitput data. In certain applications, the controller must control other instruments while the HP 8902A is making a measurement. Using the instrument's ability to issue the Service Request message when data is ready, frees the controller to process other routines until the Measuring Receiver is ready with data.
See Figure 3-3, the SRQ message to signal the controller that the data is ready.
"Example Flowchart Using the Service Request Message" for an example of using
HP 8902A has completed its measurement and the
Operation Model 8902A
Definitions of the
Status Byte bits
SRQ Mask and
- - - - - - - - - - -
-
L
UNCALIERATED
User sets to 1 to unmask condition using Special Function 22. HP-IB
Code Error bit unmasked. is permanently
- - __
- - - - - - - - -
+
SRQ MASK
STATUS BYTE
1 if condition has occurred and -c
SRQ Mask bit has been set to 1.
1 if one or more other Status Byte
0
- - - - -
-c
I I
is/rl
I
I
Asserted if ROS bit is 1.
- - - - - - - - - -
+ m
ANNUNCIATOR
- - - - - -
*
F
4:::~
~ ~ ~ ~ ~
EXCEEDED
~ c v
1
-
3-29
Operation Model 8902A
SRQ MASK
(Special
Function 22)
Overview Special Function 22 is used to set the bits of the SRQ Mask. The set SRQ Mask bits unmask the bits of the Status Byte. At power-up or Instrument Preset, all Status Byte bits are masked except the HP-IB Error Code bit. The appropriate SRQ Mask bits must be set to 1 by the operator to unmask any other Status Byte bit. Refer to Figure 3-4, "Issuing a Service Request'' for a graphic example of these relationships.
NOTE
Bit I of'the
SRQ
Mask is ptwnancntly set lo
Service Rtqi[t>.sl rnt'ssagc CA NNOT bt. disahlcd.
I ; thtwfore, an HP-IB codc error will AL WA YS gtwerafe a Service Rcqimt mcwage. This means thal rhc
Setting the SRQ Mask Only bits 0, 2, 3, 4 and 5 can be set. Bit 1 (weight=2) is permanently set.
To set the SRQ Mask bits and unmask the Status Byte bits which you want to cause the Service
Request Message to be issued:
0
Sum the weights of the desired conditions using Table 3-9 below. Use this sum as the suffix of
Special Function 22.
NOTE
Sincc Bit I (HP-I13 Code Error) is pcrmancwtly enahlcd, if thc weight is eqirivaknl to 22.2SP.
not
summed in, it will he assirmczd by tht? instrirment, for c>xampk 22.0SP is
Enter the special function code (and suffix) via the front panel, then select SPCL; or, operation, enter 22.<sufix>SP.
Example To set the SRQ Mask corresponding weights. so that the Measuring Receiver will issue a Service Request message for all conditions except Data Ready, first compute the Special Function suffix by summing the
4 + 8 + 1 6 + 3 2 = 6 0
Key in 22.60SP. (22.62SP would also work because of the permanently set HP-IB Error Code bit.)
3-30
Model 8902A Operation
Bit
Number
0
1
2
3
4
5
6
7
Mask
Weight
1
2
4
8
16
32
Data Ready
Tahk 3-9. SRQ Mask and Statirs Byte Bif Dt>scriDtion.s
Condition Description
HP-I6 Code Error
(Permanently Set)
Instrument Error
Limit Exceeded
Frequency Offset Mode Change
Recalibrate or Uncalibrated
RQS (Request Service)
Unused
Asserted if unmasked when valid data outputs to the bus. is ready after a measurement. This can be used for any function which
Asserted when an invalid code is sent to the bus, or an error is made in programming the instrument. (Always unmasked.)
Asserted if unmasked when an error is displayed on the instrument. Note that invalid bus codes are also instrument errors
Asserted if unmasked when limits are enabled (14.XSP) and exceeded
Asserted if unmasked when in Frequency Offset Mode and
Manual Tune frequency is changed, or when entering or exiting the mode through 27.0/1/3 SPCL.
Asserted if unmasked when the RECAL or UNCAL annun- ciators turn on.
This bit will always be set if any of the other bits are set.
Alwavs 0.
Reading the SRQ Mask Read the SRQ Mask by entering the mask value which is displayed and available over the and can be interpreted using Table 3-9 "SRQ
22.64SP. bus. This
This value will
Mask and Status Byte Bit initiates a "measurement"
Descriptions". of be displayed in decimal
Clearing the SRQ Mask Clear the SRQ Mask by any of the following operations:
0 entering 22.0SP (Remember this will not clear the HP-IB Code Error bit.)
0
Sending the Device Clear (DCL) message, sending Instrument instrument
.
Preset (IP) the
3-3 1
Operation
Status Byte
Model 8902A
Overview
The Status Byte bits 0-5 reflect the status of the unmasked Instrument Conditions. Refer to Table
3-9, "SRQ Mask and Status Byte Bit Descriptions" for bit definitions. At power-up and Instrument
Preset, the only Status Byte bit which is unmasked is the HP-IB Error Code bit.
The RQS bit (bit 6) is automatically set if any other bit in the Status Byte is set true. When the RQS bit is set, the Service Request message is sent. The front-panel SRQ annunciator turns on at the next front-panel display update. Once any Status Byte bit has been set, it remains set until the Status Byte is read.
If one of these Instrument Conditions occurs, while it is masked by the SRQ Mask, NEITHER the
Status Byte bit corresponding to the condition NOR the RQS bit will be set, and the Service Request message will not be sent.
Reading the Status Byte
NOTE
0
A Statirs Byte Bit that read as be read
as
a
one,
is not irnmnskcd by the SRQ Mask will AL WA and then only (fits initiating Instrirment Condition
occiirs
AFTER it is irnmasked.
YS is read. Only an irnmasked bit can
0
Reading the Statirs Byte is the only accirrate way
to
the SRQ hiis
h e .
to determine the condition of the SRQ biis line (Service Request message). The SRQ annrinciafor is only irpdafcd as the front panel is updated. If is ticd directly
NOT
0
The Measuring Rtwivtv cannot mode; thertgore, if is not waitingjor a condifion fo caiise
a k r a bit
the Sfatirs Byte while in stjrial poll
to
be sd. a
Rcading Stuf
11s of non-cxisftw f dcvim (HP-IB addrc.ssc>s hang the HP 8902A HP-IB and rtyirircs to clear the birs.
a
in irse) will
Device Clear (DCL) message
The Status Byte can be read using a serial poll, only if the instrument sends a Service Request
Message. Only those bits which are unmasked by the SRQ Mask can be read accurately.
Talk Status Only causes the instrument to only output the Status Byte. Refer to "TALK and
Status Descriptions" for more information.
LISTEN
3-32
Model 8902A Operation
Clearing the Status Byte
NOTE
Remolt>-to-Local transitions will not clear the
Status
Byte.
Once bits in the Status Byte are set, they can be cleared by the following operations.
0
Reading the Status Byte by serial polling AFTER the condition is cleared. If the condition which set the bits persists, those. bits and the RQS bit will again be set.
0
Sending the Device Clear (DCL) message, presetting or powering up the instrument.
0
In Talk Status Only, the Status Byte is cleared each time the one-byte Data message is issued to the bus
0
Sending the Serial Poll Disable
Sending the Abort message.
Abort
Abort abruptly terminates all listener/talker activity on the interface bus and prepares all instruments to receive a new command from the controller. Typically this is an initialization command used to place the bus in a known starting condition. The Measuring Receiver stops listening it receives the Abort message. or talking when
Pass Control/Take Control
The Measuring Receiver does not respond to the Pass Control/Take Control message because it cannot act as a controller.
Status Bit
The Measuring Receiver does not implement parallel poll operations and therefore cannot send the
Status Bit message. The Status Bit should not be confused with the Status Byte which was discussed previous1 y under "Status Byte".
3-1
1.
ADDITIONAL INFORMATION
Annunciators
REMOTE Light: Lights when the instrument is operating in remote mode. When the Measuring
Receiver goes to local operation, the front-panel REMOTE annunciator turns off.
LISTEN Light: Lights when the instrument is addressed to Listen.
TALK Light: Lights when the instrument is addressed to Talk.
SRQ Light: Lights when the Service Request message has been sent (SRQ line true), and the front panel has been updated.
3-33
Operation Model 8902A
Reading the
HP-IB
Address
Switch
and
SRQ Status
The HP-IB display the state of the HP-IB address switch and the SRQ 21.0SP.
To
This display does not time out. To clear the instrument display, press the CLEAR key.
The format of the display is as follows;
AAAAA.TLS where AAAAA is a five-bit binary address with leading zeros blanked and TLS represent the status of the TON switch, LON switch and SRQ
NOTE
IJT und L urc holh I , rhc instriimcwl is s d lo Talk Only (Tulk Only overrides Lislen Only ).
Ifall A hits arc I and T is I , the instriimcnt will Talk Sfafiis Only (that is. oiitpirl the sta1ii.s hyle only).
A list of possible conditions of the TLS digits of the display is provided in the following table:
Operating Mode
Talk and Listen
Talk Only
Talk Status Only
Listen Only
T Digit
0
1
I *
0
L Digit
0
1 or 0
1 or
1
0
S Digit
1 or0
1 o r 0
1 o r 0
1 or 0
Example If 11 10.001
Talk and Listen. The is the address displayed, then the
S digit is and the L digit is
1
"0"
HP-IB address is 11 10 in binary (that is, 14 to indicating that the instrument is issuing a Service Request Message.
For the same example, if the about Talk Only, Listen Only, SRQ is displayed.)
= 14 will be displayed. (No information
Setting the HP-IB Address The Measuring Receiver's talk and listen addresses are switch selectable
as described in paragraph 2-7. Refer to Table
address codes.
for a comprehensive listing of all valid HP-IB
Updating the HP-I8 Address Display The HP-IB address display is continuously updated. When the switch setting is changed, the result is immediately visible on the display.
3-34
Model 8902A Operation
TALK and LISTEN Status Descriptions
Talk Only Mode If the internal address switches are set to a valid address and the TON (Talk Only) switch is set to "i", the Measuring Receiver is placed in the Talk Only mode. This mode causes the instrument to output data each time a measurement is made. Each time the measurement is completed, data will be output to the bus unless the listening device is not ready for data. If the listener is not ready, and the Measuring Receiver is in Free Run mode (TO), another measurement cycle is executed. to "l",
Mode If the five internal address switches and the TON (Talk Only) switch are set the Measuring Receiver is placed in the Talk Status Only mode. In this mode the instrument is configured to send a one-byte data message whenever the bus is in the data mode. The byte sent is an exact copy of the Status Byte. Each time this byte is successfully sent on the bus, the internal
Status Byte is cleared. The Data Valid (DAV) handshake line is pulsed each time the one-byte Data message is sent.
Listen Only Mode Listen Only mode is provided to allow the Measuring Receiver to accept programming from devices other than controllers (for example, card readers).
If the internal LON (Listen Only) switch is set to "1" and the TON (Talk Only) switch is set to "0, the Measuring Receiver is placed in the Listen Only mode when the remote enable bus control line
(REN) is set true. The instrument then responds to all Data messages, and the Trigger, Clear, and
Local Lockout messages. However, it is inhibited from responding to the Local and from responding to a serial poll with the Status Byte message.
Abort messages
Code Execution in the Measuring Receiver
Some things to consider when programming the HP 8902A are listed below. The following discussion of the Software Supervisor is included to elaborate on these considerations.
Every two-letter command is acted upon, in order, in software state.
Hardware State equals the Software State only after the end of the code string AND a pause occurs allowing the instrument to implement the commands it has received (e.g., time delay between code strings when data is read from the instrument).
HP-IB
Only one measurement mode may be loaded from Software state e.g., D2 PI to Hardware state at a time;
HI L2. For fail-safe operation, only use one measurement code per code string
Modes and Codes" for a complete list of all the functions defined as Measurement Modes.
Keyboard or HP-IB commands may not be implemented in hardware stat.e during a measure- is not significant to a particular measurement. Re-
fer to Table 3-13, "Measurement Modes and Codes" and Table 3-
14, "Measurement Modifiers" for more information.
The Software Supervisor is the program that controlls overall instrument operation and controls the implementation of commands received from the external controller. (See Figure 3-5, 'Software
Supervisor Flowchart".) It is a loop that is continuously executed, with measurements made near the end after checks for proper frequency tuning, proper RF and IF level, and correct audio range.
After arithmetic manipulation (e.g., for the RATIO function), the program loops back up to display the measurement.
The Software Supervisor controls the setup of the instrument for a measurement by making use of two concepts called Software State and Hardware State. Each of these is updated independently.
The Software State is located in RAM and contains a software image of the state of the instrument.
On power-up, the initialization procedure loads the initial Software State from ROM. (Refer to
3-35
Operation Model 8902A
“Instrument Preset“ in the made to
Detailed Operating Instrirctions instrument condtions.) The conform with the on page 3-239 for a description of the intial block in the supervisor is where the hardware state is
The. hardware state is the actual, current state of the internal settings of the instrument and is only updated when enough time loop to is allowed between commands for the Software Supervisor measurement be completed successfully without interruption; e.g., when a trigger is received. made and
1-1 to blocks manipulate hardware as well and also make an accurate measurement. until all blocks are successfully completed in succession. If a block measurement is not not completed, a negative decision after that block then forces the program back for that loop. to the top of the supervisor, bypassing
In a normal, stable measurement cycle, the program takes the of the supervisor and so if the program loops back before taking a measurement,
INon-Measurement Dlsplay]
1‘-
”,
1 1-
1 1branch at the top block. However, if an error condition exists, the branch will be traversed. This will light an appropriate display, which is usually block.
After power-up, the external system controller can be thought
7 1 .
of state. Controller commands ( Keyboard or HP-IB interrupts] ) are treated as non-returnable interrupts and break the flow around the So are Supervisor loop, forcing the internal microprocessor to execute a short program to change the software state and then return to the loop as shown in the diagram.
The commands applicable to the measurement mode are implemented in software state and then in hardware state at the next
NOTE
Controller roirfines modfy only the sojlware state and do not a@ct the hardware immedia tcly.
Since a IKeyboard or HP-IB interrupt] and retirrn it to the point in the can loop infcw’irpf before
-1, the Sirptv’visor af any point these inft’rnipts abort thc cirrrcnf mt’asiircmcnt and start a new measiirc~ment cycle.
The adiral insfriimenf sdirp
is
guarankw/ lo only at the rnomcnl a mcaasirrcmcnl is lakcw (
F l ) .
Keyboard ri~qi~iW
3-36
Model 8902A
I
CHANGE
SOFTWARE STATE
I
I
HARDWARE
DISPLAY
I
Operation
I GNAL
I , , , ,
MEASUREMENT
T
YES
I I
Figiirc 3-5. Sofi warc Siipervisor Flowcharl
3-37
Operation
Function
MEASUREMENTS
AM
FM
WvI
RF POWER
FREQ
AUDIO FREQ
AUDIO DISTN
IF LEVEL
TUNED RF LEVEL
FREQ ERROR
DETECTORS
PEAK+
PEAK
-
PEAK HOLD
AVG (RMS Calibrated)
1 kHz DISTN
400 Hz DlSTN
RMS
PEAK 342
DISPLAYS
Display LOG Result
Display LIN Result dB EXT ATTEN off dB EXT ATTEN on
RATIO Off
RATIO On
PREVIOUS RATIO
FILTERS
HP (High-Pass) FILTERS Off
50 Hz FILTER On
300 Hz FILTER On
LP (Low-Pass) FILTERS Off
3 kHz FILTER On
15 kHz FILTER On
>20 kHz FILTER On
FM DE-EMPHASIS
PRE-DISPLAY Off and
FM DE-EMPHASIS Off
PRE-DISPLAY On and
FM DE-EMPHASIS On
25 /./.S DE-EMPHASIS
50
/IS DE-EMPHASIS
75
/./.s
DE-EMPHASIS
750
/AS
DE-EMPHASIS
1. Mcasirring Rcwivcr Firncfion
fo
Codc Sirmmary
Code
~~~~
Function
M1
M2
M3
M4 s1 s2 s3
54
55
CALIBRATION
CALIBRATE Off
CALIBRATE On
GAL FACTOR
O/o
SET REF
ZERO
SAVE CAL
LG
LN
NO
N1
RO
R1
R2
D1
D2
D3
D4
D5
D6
08
D9
MANUAL OPERATIONS
AUTO TUNING
ENABLE ERRORS
DISABLE ERRORS
CLEAR (KEY)
DISPLAY FREQ
DISPLAY INCREMENT
INPUT FREQUENCY (Hz)
11.
Hz
U Hz
TRACK Mode Off (Lock Mode)
TRACK Mode On
4
MHz (INPUT FREQ)
RECALL
STORE
SPECIAL FUNCTION
SPECIAL, SPECIAL mV Units
FV
V
Units
Units
W Units
P1
P2
P3
P4
P5
HO
HI
H2
LO
L1
L2
L3
PO
MISCELLANEOUS
MODULATION OUTPUT
AUDIO INPUT
AUTOMATIC OPERATION
Auto-Ranging (RANGE HOLD Off)
RANGE HOLD
Identify Instrument
INSTR PRESET (same
Trigger Off
Hold
Trigger Immediate
Trigger with Settling
Hexidecimal A
Hexidecimal
Hexidecimal
B
Hexidecimal C
Hexidecimal D
Hexidecimal E
F as DCL)
Model 8902A
Code co
CF
RF
ZR sc
HD
KO
K1
KU
KD
MZ
RC
TR
SP
AT
BO
B1
CL
FR
FN
HZ
HU ss
MV uv
VL
WT
G1
ID
IP
TO
A0
A1
AU
GO
T1
T2
T3 xo x1 x2 x3 x4 x5
3-38
Model
11YUZA
1
Code
A0
A1
AT
AU
BO
61
HO
H1
H2
HU
HD
HZ
ID
IP
FR
FN
GO
G1
CF
CL
D1
D2
D3
D4
D5
D6
D8
D9
LO
L1
L2
L3
LG
LN
KO
K1
KU
KD
Tnhk 3- 12. Codc lo
Function
Mensitring
Rtwivcv
Flintlion Summary
Code Function
MODULATION OUTPUT
AUDIO INPUT
AUTO TUNING
AUTOMATIC OPERATION
ENABLE ERRORS
DISABLE ERRORS
CALIBRATE Off
CALIBRATE On
O/o
GAL FACTOR
CLEAR (KEY)
M1
M2
M3
M4
M5
MV
MZ
NO
N1
PO
AM
FM
(PM
RF POWER
FREQ mV Units
MHz (INPUT FREQ) dB EXT ATTEN Off dB EXT ATTEN On
PEAK+
PEAK
PEAK HOLD
AVG (RMS Calibrated)
1 kHz DISTN
400 Hz DISTN
RMS
PEAK 342
DISPLAY FREQ
DISPLAY INCREMENT
Auto-Ranging (RANGE HOLD Off)
RANGE HOLD
HP (High-Pass) FILTERS Off
50 Hz FILTER On
300 Hz FILTER On fi Hz
U Hz
INPUT FREQUENCY (Hz)
P1
P2
P3
P4
P5 s1 s2 s3 s4 s5 sc
SP ss
RO
R1
R2
RC
RF
PRE-DISPLAY Off and
FM DE-EMPHASIS Off
PRE-DISPLAY On and DE-EMPHASIS On
25 /AS DE-EMPHASIS
50 /AS DE-EMPHASIS
75 /AS DE-EMPHASIS
750 /AS DE-EMPHASIS
RATIO Off
RATIO On
PREVIOUS RATIO
RECALL
SET REF
AUDIO FREQ
AUDIO DISTN
IF LEVEL
TUNED RF LEVEL
FREQ ERROR
SAVE GAL
SPECIAL FUNCTION
SPECIAL, SPECIAL
Identify Instrument
INSTR PRESET (same as DCL)
TRACK Mode Off (lock mode)
TRACK Mode On
4 kHz kHz
LP (Low-Pass) FILTERS Off
3 kHz FILTER On
15 kHz FILTER On
>20 kHz FILTER On
Display LOG Result
Display LIN Result
TO
T1
T2
T3
TR uv
VL
WT x2 x3 x4 x5
ZR
Trigger Off
Hold
Trigger Immediate
Trigger with Settling
STORE pV Units
V Units
W Units
Hexidecimal A
Hexidecimal B
Hexidecimal C
Hexidecimal D
Hexidecimal E
Hexidecimal F
ZERO
Operation
3-39
Operation
Model
8902A
~~ ~
Measurement Mode
Tahk 3-13. Measirremmf M0de.s and Codes (I of 2)
A M
AM Calibration
AM Calibration Actual
AM Residual Calibration
AM Peak Residual Calibration
Read AM Calibration Factor
Program Code
M1 co, c1
13.0SP
13.1SP
13.2SP
16.2SP
Receiver
Used?
Yes
Yes
No
Yes
Yes
No
Volatile?
No
No
NO
No
No
Yes
Blanks
Demod.
Output?
No
No
Yes
No
No
No
FM
FM Calibration
FM Calibration Actual
FM Residual Calibration
FM Peak Calibration
Read FM Calibration Factors
M2 co, c1
12.0SP
12.1SP
12.2SP
17.2SP
Yes
Yes
No
Yes
Yes
No
No
No
No
No
No
Yes
No
No
Yes
No
No
No
M3 Yes No No iPM
RF Power (Power Sensor)
RF Power Zeroing
RF Power Calibration Factor Status
RF Power Calibration Factor Table Size
RF Level (RF Peak Detector)
M4
ZR
37.2SP
37.4SP
35.XSP
No
No
No
No
No
No
Yes
Yes
Yes
No
Yes
Yes
No
No
Yes
Tuned RF Level
Tuned RF Level (Synchronous and Average)
Peak Tuned RF Level s4
4.XSP
36.XSP
Yes
Yes
Yes
No
No
No
Yes
Yes
Yes s3 Yes No No IF Level
Frequency
LO Frequency
IF Frequency
Frequency Error
M5
33.XSP
34.XSP s5
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
~
Audio
Audio Frequency (External).
Audio Distortion (External)*
Audio SINAD (External).
Audio RMS Level (External)
S1 A2
S2 A2
29.0SP A2
3O.XSP
..
A1 to select internal audio measurements. Internal audio measurements use I
The demodulated Output Is not blanked during internal Audio measurements.
No
No
No
No
~~~
Recelver .
No
No
No
No
Yes.'
Yes **
Yes **
Yes **
3-40
Model 8902A Operation
Measurement Mode
Tahlc 3-13.
Measirrcment
Modcs and Codcs (2 of2)
~ Other Measuring Capabilities
Squelched Tone Receiver
Timebase Oven Hot/Cold
'
Timebase Internal/External
Reading Internal User Information
HP-IB Address
Display Ext. LO Freq
Display Operator Selected Special Functions
Display Instrument Selected Special Functions
Display Ext. Atten.
HP-IB Identify (89018
Display SRQ Mask
Software Date Code or 8902A?)
Read Ratio Reference
Read Lower Limit
Read Upper Limit
Read Lower Limit Measurement Code
Read Upper Limit Measurement Code
18.XSP
15.0SP
15.1SP
21 .XSP
27.2SP
SP ss
25.2SP
ID
22.64SP
42.XSP
11.2SP
14.5SP
14.6SP
14.7SP
14.8SP
Receiver
Used?
Yes
No
No
No
No
No
No
No
NO
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Volatile?
Yes
Yes
Yes
Blanks
Demad. output?
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
3-4 1
Measurement and Code
AM Measurement (Mi)
AM Calibration (CO, C1 and CF)
AM Calibrator (13.XSP)
FM Measurement (M2)
FM Calibration (CO, C1 and CF)
FM Calibrator (1P.XSP)
Ranges Detectors
(Dl -9)
3 (2.XSP)
N/A
Peak (+
Peak (+ or
Ava. or RMS or
-),
-)
Fixes (2XSP) Peak (+ or -)
4 (2.XSP) Peak (+
Avg, or or -),
RMS
N/A Peak (+ or -)
Fixes (2.XSP) Peak (+ or -)
I
Variable Parameters
Filters De-emphasis Calibration Frequency
(HO-2
LO-3
Yes and I (0-5)
N/A
I Factors
Yes
I Offset
~~
Tuning
T
~~ dB Ext.
Attenuator
N/A
N/A
N/A
Yes
N/A
N/A
Yes
Yes
N/A
Yes
N/A
N/A
Tuning
~
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Yes
N/A
N/A
N/A
N/A
N/A
(M3)
RF Power Measurement (M4)
4 (2.XSP)
5* (1O.XSP)
Peak (+ or -),
Avg, or RMS
I
RF Power Sensor
I
Yes
N/A
1
N/A
N/A
I
Yes (FM)
Yes
I
Tuning
Yes
Tuned RF Level Measurement (S4)
(includes Synchronous and Average)
IF Synch., IF Avg.
( 4 . x ~ ~ )
N/A N/A Yes Tuning
I
I
I
Peak RF Level (35.XSP)
I
Peak Tuned RF Level (36.XSP)
Set Reference (RF)
IF Level Measurement (S3)
+
1 (Power Sen- sor)
N/A
N/A
3 (1.XSP)
N/A
RF Peak
IF Peak
IF Synch., IF Avg.
(4.XSP) I
IF Avg
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Yes
N/A
Tuning
Tuning
RF Power has two completely independent tables for calibration factors. one used in normal operation and one used when Frequency Offset mode is active.
0.15--2.5 2.5-10 MHz, and 10--1300
I
N/A
Yes
Yes
Yes
Yes
Yes
~~
Limit/
-
Yes
Yes
-
-
w w
Measurement and Code
RF Frequency Measurement (M5)
LO Frequency (33.XSP)
IF Frequency (34.XSP)
Frequency Error Measurement (S5)
Ranges
Audio Measurements t
* I
Audio Frequency
Audio Distortion (S2)
External Audio
SlNAD (29.XSP)
(SI)
RMS Level (3O.XSP)
0 15-2.5 MHz, 2.5-1 0 MHz. and 10--1300 MHz.
N/A
N/A
N/A
N/A
3-
N/A
N/A
3**
N/A
1
1
N/A
N/A
RMS
RMS
RMS
Detectors
(Dl-9)
Variable Parameters
Filters De-emphasis Calibration
(HO-2
LO-3 and (0-5) Factors
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A N/A N/A
N/A
Yes
N/A
Yes
N/A
Yes (FM)
N/A
Yes (FM)
N/A
N/A
N/A
N/A
Yes
N/A
N/A
Tuning
Tuning
Tuning
N/A
Tuning
Frequency
Offset
N/A
N /A
N/A
NIA
N/A
N /A dB Ext.
Attenuator -1
Yes
Yes
Limit/
Ratio
Parameter and Code
Calibration Factors
Default Value To See Valuels To Re-enable Dis-able
AM (16.XSP)
FM (17.XSP)
100%
100%
16.2SP, or
AM/ o/o
Cal Factor *
17.2SP, or
FM/ o/o
Gal Factor
RF Power/
%Cal Factor *
*
16.1 SP
17.1SP
16.0SP
17.0SP
RF Power ** (37.XSP) N/A
Tuned RF Level
(38.XSP and 39.XSP)
ROM Table 38.1-3SPJ or Tuned RF Level/
%Cal Factor *
37.0SP
(Automatic)
37.1 SP
(Manual)
Freq back to valid point (Valid)
39.9SP (Default)
Auto Op, or
37.0SP
Change freq.,
Frequency Offset
(27.XSP) dB External Attenuation
(25.XSP)
Ratio
(11.XSP)
Limits
(14.XSP)
0 MHz
0 dB
100
27.2SP
25.2SP
11.2SP
0.15 and
(Code
1300 14.5SP,
5=freq) 14.6SP or
27.1SP dB EXT ATTEN
Previous Ratio
14.3SP,
14.4SP or
FMI
O/O
CAI Factor *
37.2SP
27.0SP dB EXT ATTEN
Ratio Key f OFS light dB Ext Atten light
Ratio Key Light
14.0SP
To See Status
AM
O/O
Cal Factor *
Uncal light, or
Tuned RF Level/ o/o
Cal Factor *
14.9SP
Set Reference
(26.XSP)
0 dBm N/A 26.1SP Tuned RF Level, or 26.0SP dB Annunciator lo Enter Value and Enable
I
Misc.
SAVE GAL
SAVE CAL
RF Power/
O/O
Cal Factor, or 37.1SP
GAL or 39.1, 2, 3SP
27.3SP/ nn/ MHz nn/dB EXT ATTEN
I
N/A
37.3-6, 9SP
(edit CF Tables)
Ratio Key/ or nnn/
Ratio Kev
14.1SP,
14.2SP or
(from Ratio)
Tuned RF Level/
Set Ref.
14.7SP,
14.8SP or
(measurement mode)
N/A
**
Two tables of RF Power Calibration Factors are available. The table being used is determined by the status of the Frequency Offset Mode.
I
Parameter and Code
I
AM (16.XSP)
FM (17.XSP)
RF Power ** (37.XSP)
100%
100%
N/A
To See Valuels
16.2SP or M1 CF
17.2SP or M2 CF *
M4 CF *
To Re-enable
16.1SP
I
17.1SP
37.0SP
(Automatic)
Disable
16.0SP
17.0SP
AU or 37.0SP
To See Status
M1 CF
M2 CF *
37.2SP
I
T;;;te;e~e
M1 C1 SC
M2C1 SC
M4 nnn CF or 37.1SP
I
M i C .
N/A
N/A
37.3-6, 9SP (edit
CF Tables)
I
I
(38.XSP and 39.XSP)
ROM Table or s4 CF *
Change freq. Uncal light, or
S4 CF *
S4C1 or
39.1, 2, 3SP
N/A
Frequency Offset
(27.XSP) dB External Attenuation
(25.XSP)
Ratio
I1
Limits
(1kXSP)
SetRe ference
(26.XSP)
*
Ofo
0 MHz
0 dB
100
0.15 and 1300
(Code 5=freq:
0 d6m
27.2SP
25.2SP
11.2SP
14.5SP, or
14.6SP
I
1 valid point
(Valid)
39.9SP
(Default)
27.1sp
N1
R2
14.3SP, or
14.4SP
27.0SP
NO
RO
14.0SP
S4 or 26.0SP f OFS light dB Ext Atten
Light
14.9SP dB Annunciator I
27.3SP nn MZ
I 1 nn NI
Ratio Key Light R1 or nnn R1
14.1SP, or
14.2SP
(from Ratio)
I
I
S4 RF
I I
N/A
I
N/A
N/A
14.7SP, o r
~
14.8SP
(measurement mode code)
N/A
Cal Factor alone shows the value currently being used. For AM, FM. and Synch. and Avg. Tuned RF Level, it also indicates enabledldisabled status by display resolution. 0.01% resolution indicates enabled and 1% resolution indicates disabled. t f Two tables of RF Power Calibration Factors are available. The table being used is determined by the status of the Frequency Offset Mode.
~
I
I
1
~
Operation
HP 8901A
3-1 7. HP 13901A/OZA Codc Dix2rcncc.s
HP 8902A Functions
AI (or AU)
F1 (or MZ)
F2 (or KU)
F3 (or KD)
F4 (or 24 or SP)
F5 (or 25 or SS)
K1 (or CL)
U1 (or DI)
U2 (or 02)
U3 (or D3)
U4 (or D4)
Z1 (or HZ)
22 (or HU)
23 (or HD)
M4
54
R1
R2
4.0SP
4.1 SP
4.2SP
7.1SP
7.2SP
9.OSP
1O.OSP
11 .OSP
11.1SP
11.3SP
15.0SP
Status
Byte
AU
MZ
KU
KD
SP ss
CL
D1
D2
D3
D4
AUTOMATIC OPERATION
MHz (INPUT FREQ)
.h kHz
U kHz
SPECIAL
SPECIAL, SPECIAL
CLEAR
PEAK+
PEAK
-
PEAK HOLD
Average Detector (RMS Calibrated)
HZ
HU
HD
35.0SP
36.0SP
LN, R1
LG, R1
Hz INPUT FREQ
0 Hz
U Hz
Peak RF Level
Peak Tuned RF Level
Oi'o
RATIO dB RATIO
Auto Tuning, low-noise lock mode
Auto Tuning, track mode
Manual Tuning, low-noise lock mode
AT, KO
AT, K1
MZ,
7.1 SP
7.3SP
GI
34.OSP
LN, R2
LG, R2
Jse "-" key
15.0SP
Status
Byte
10 Hz frequency resolution
1000 H t frequency resolution
Hold Setting (RANGE HOLD)
IF Frequency
Yo PREVIOUS RATIO dB PREVIOUS RATIO
Make Ratio Reference Negative
3ven Check (returns. "0" if oven OK
3s in the 8901A) or lot installed, rather than doing nothing
Status Byte Bits "Upper Limit" (weight
5) and "Lower Limit" (weight 16) are nerged together into "Limit Reached"
[weight 8)
Model 8902A
3-46
Model
8902A
Operation
3-12. BASIC FUNCTIONAL CHECKS OF THE MEASURING RECEIVER
Description
Using a signal generator, an oscilloscope, and is verified. a sensor module, the overall operation of the Measuring
Equipment
Oscilloscope
.................................................................
Sensor Module
Signal Generator..
........................................
HP 864OB
HP 1740A
HP 11722A
Option 001 and 002
The HP
Option modify
8656B, and 002 some testa. is
8663A, HP 8654A or HP 8654B can also be used if an HP will
864OB need to
Procedure
Pteliminary Check
1.
2.
Connect the
3-6).
After the
FU? coaxial cable of the sensor module to the sequence, the instrument should display to
INPUT
"--".
500
The connector
All LEDs should light
MHz
(see Figure annunciator, the
FM annunciator under MODULATION OUTPUT, the AUTO TUNING annunciator (under the TRACK MODE key), and the FREQ key should be lighted. the SENSOR input connector.
Select
INSTR
PRESET (Blue Key, AUTOMATIC OPERATION). Observe the front-panel
LED annunciators, display segments and decimal points, and key lights. for approximately 10 seconds at
turn
on and then all should momentarily
turn
off. rev. 1
wuL87
BASIC FUNCTIONAL CHECKS OF THE MEASURING RECEIVER 3-47
Operation Model 8902A
RF Power Calibration Check
3. Connect the sensor module input to the RF
(See Figure 3-6.)
POWER CALIBRATION OUTPUT connector.
I o
HP a 9 m
0
0
0
INPUT
SENSOR MODULE
Figitre 3-6. RF Powu Calihrafion St’1itp
4. Press the RF POWER key. If the instrument does not display Error 15, proceed with step
If the instrument displays Error entered), proceed with step 5.
I5 (indicating the RF
6. power calibration factors have not been
5. If the instrument displays Error 15, enter the RF power calibration factors that are given on the cover of the sensor module. (Note that a software driven alternative for a program list in BASIC for the HP Series 200 computers.): is available. See R F Powcr a. Enter the reference calibration factor by keying in 37.3 and pressing the SPCL key. Then, key in the value of the reference calibration factor and press the Blue key then the
O/o
CAL FACTOR key (the MHz key). b. Enter each frequency/calibration factor pair by first keying in 37.3 and pressing the SPCL key.
Next, key in the frequency (in MHz) and press the MHz key. Then, key in the value of the calibration factor and press the Blue key then the Yo CAL FACTOR key.
3-48
Model 8902A Operation
NOTE
Error 15 will continlit’ to intt~rpokcfr bti!wtw
a
.fi.t.rliic’ncy/salihrarion
Power Calibration Factors in scic(ion.)
10 htj displaytd tht? iinfil thc Mtmiiring Receiwr is ablt’
RF factor pair #om /hose and
Detailed Operating Instructions pairs in this
6. Press the ZERO key. ‘‘ - - -
-” should be displayed for approximately should then be displayed briefly, and then a value less than 3.0 -06 W seconds,
(that is, 3.0
0.0 00 p W )
W should
7. Press the CALIBRATE key. When a value appears in the display, press the Blue key and
CAL key (the CALIBRATE key). The display should show between
W (that pW). is, 0.999 and 1.000 the CALIBRATE key again. or between 999 -06 and
The RECAL and UNCAL annunciators should be Turn off
0.999 -03 and 1.000
(that is, 999 and
-03 the calibrator by pressing
RF Power Check
8. Set the signal generator to 100 MHz CW at - 10 dBm (as measured on its level meter).
9. Connect the input of the sensor module to the RF output of the signal generator. Connect the MODULATION OUTPUT/AUDIO INPUT to the vertical input of the oscilloscope. (See
Figure 3-7.)
10. Press the LOG/LIN key to display power in dBm. The Measuring Receiver should display between - 11.00 and -9.00 dBm.
3-49
Operation Model 8902A
RF Peak Level Check
11. Key in 35.0 and press the SPCL key (uses a peak detector to measure power). The Measuring
Receiver should display between - and -6.00 dBm.
Frequency Check
12.
10 Hz.
7.1 and press the SPCL key to set the RF frequency resolution to frequency display wit,h the Measuring Receiver’s display. The two displays should agree within the limits indicated.
I
Signal Generator
Frequency (MHz)
I
Frequency Difference
Limits (fHz)
2
4
8
16
25
50
100
200
400
800
40
50
70
100
130
230
430
830
1600
3200
13. Set the signal generator frequency to signal, press the MHz key to disable the automatic tuning and enable manual tuning. Press the
(Shift) key and the FREQ ERROR key (the FREQ key). The Measuring Receiver should display between -1 and 1 kHz.
50
S
14. Key in and -99
100 and press the kHz. Key in automatic selection.
7.0 fi and press the SPCL key
-101 to return the RF frequency resolution to
Track Mode Tuning Check
15.
Press the
AUTOMATIC OPERATION
key then the FREQ key. Press the
TRACK
MODE key. Manually sweep the signal generator’s frequency to 64 MHz. The Measuring Receiver’s frequency display should track the frequency as it changes. Press the TRACK MODE key again to turn off the function.
3-50
Model 8902A
AM and FM Calibration Check
16. Connect the input of the sensor module to the AM/FM CALIBRATION
OUTPUT
Opera tion
I,
HP 8902A
0
Figure 3-8. A M and FM Calihralion Chc.c.k StVirp
17. Press the AM key then the CALIBRATE key. After approximately calibration factor should be displayed, The displayed value should be between
10 1 .ooo/o.
20 seconds, the AM
99.00 and
18. Press the factor should key then CALIBRATE key. After approximately 20 seconds, be displayed. The displayed value should be between to turn off FM
99.00 the and
FM calibration
101.OOo/o. Press calibration. (If you remove the sensor with the
3-5 1
Operation Model 8902A
AM Check
19. Reconnect the sensor module input to
the signal generator’s output. (See Figure 3-9.)
0
HP 8902A
0
60 om
SENSOR MODULE
INPUT
I RF OUTPUT
SIQNAL GENERATOR
Figure 3-9. A M Check Setup
20. Press the Measuring Receiver’s MHz key. Set the signal generator for 50% AM (as measured on its AM meter) at a I kHz rate.
21. Press the A M key. The Measuring Receiver should display between 46.0 and 54.Oo/o.
22. Set the signal generator’s AM to should display between 22.00
25% with 0.01Yo resolution.
FM and Phase Modulation ((PM) Checks
23. Set the signal generator’s AM meter) at a and 55.0
1 kHz. off and set FM to 50 kHz peak deviation (as measured on its FM kHz rate. Press the FM key. The Measuring Receiver should display between 45.0
24. Adjust the signal generator’s FM peak deviation
Receiver. for 50 kHz as displayed by the Measuring
25. Press the (PM key. The instrument should display between 45.0 and 55.0 rad.
3-52
Model 8902A Operation
FM De-emphasis Check
26. Press the FM key. Press the RATIO key. If the display is in dB, press the LOG/LIN key to display Yo. a period of
The instrument should display between 99.8 and
1 ms.
100.2% REL. The oscilloscope and
27. Press the LOG/LIN key. Press the RATIO key. Press the PRE-DISPLAY key.-Set the FM rate as listed in the following table. For each setting, perform the following steps: a. Set the FM DE-EMPHASIS table. off if it is on. (Leave PRE-DISPLAY on.) b. Set the signal generator’s FM modulation rate to a value approximate to that listed in the c. Press the RATIO key to establish a reference of 0 dB. e. f. Press the S
-3.0 dB.
(Shift) key then press the AUDIO FREQ key (the AM key). The Measuring should change proportionately with the display. (Allow for a times output of
750 ps.)
10 amplitude at the
MODULATION OUTPUT/AUDIO INPUT when FM DE-EMPHASIS is set to
Approximate
FM Modulation Rate
FM DE-EMPHASIS
Time Constant
(A
25
50
75
750
I
Frequency Limits (Hz)
I
205.8 21 8.7
Audio Frequency and Audio Filters Check
28. Set FM DE-EMPHASIS and PRE-DISPLAY off. Set the FM rate as listed in the following table.
For each setting, perform the following steps: a. Set the HP FILTER and LP FILTER to ALL OFF. b. Set the signal generator’s FM rate as listed in the table. c. Press the FM
-3.0 key then press the RATIO key to establish dB REL. a reference of e. Press the S (Shift) key then the AUDIO FREQ key and note the FM rate. The Measuring
Receiver should display a rate within the limits listed.
0 dB. d. Set the HP or LP FILTER as listed in the table, and fine adjust the FM rate for a reading of
Approximate
FM Modulation Rate HP or LP Filter
300
3 000
15 000
90 000
50 Hz HP
300 Hz HP
3 kHz LP
15 kHz LP
>20 kHr LP
Minimum
47.5
285
2 850
14 250
80 000
Maximum
52.5
31 5
3 150
15 750
140 750
3-53
Operation Model 8902A
Audio Distortion and SINAD Check
29. Press the AM key and set the LP FILTER to ALL OFF. Set the signal generator’s FM off, set the AM depth
Press the to should be less than 3%. the Blue key then the
50%
(The display should also indicate
400
(as measured on the Measuring Receiver’s display) at
(Shift) key then the AUDIO DISTN key (the
Hz DISTN key (the PEAK-
1
FM key). The displayed distortion kHz. If key).)
400 Hz a 1 kHz rate. is displayed. press
30. Set the signal generator’s AM for a 400 Hz rate. Press the Blue key then the
(the PEAK- key). The displayed distortion should be less than 3%.
400 Hz DISTN key
31. Press the LOG/LIN
The displayed key to display the distortion in dB. Key in
SINAD should be greater than 30 dB.
29.0 and press the SPCL key.
External Audio RMS Level Check
32. Connect the audio ( A M or trigger) output of the signal generator to the input of the oscilloscope.
(See Figure 3-10.) Set the signal generator’s audio output level for oscilloscope.
3 Vpp as read on the
I
HP ~ Q W A
1
I
3-54
Figiirr 3-1 0. External A iidio RMS Level Chcck
Sef
ifp
33. Connect the audio output of the signal generator to the MODULATION OUTPUT/AUDIO
INPUT of the Measuring Receiver. (See step 33 of Figure 3-10.) Key in 30.0 and press the SPCL key. If the display is in dB V, press the LOG/LIN key to display V. The Measuring Receiver’s displayed level should be between 0.95 and 1.17V.
Model 8902A Operation
Audio Detector Check
34. Disconnect the signal generator’s audio output. Press the FM key. Set the signal generator’s AM off and set the FM on with a peak deviation of key then the LOG/LIN key to Yo to establish a reference of 100%. Set. DETECTOR to PEAK-.
The Measuring Receiver should display between generator’s FM distortion.
50
95 kHz and a rate of I kHz. Press the RATIO and 105% REL depending upon the signal
35. Set DETECTOR to PEAKf/2 by pressing both the PEAK+ and PEAK- keys simultaneously.
The Measuring Receiver should display a value between 100Yo and the value read in step 34.
36. Press the AVG key. The instrument should display between function off by pressing the RATIO key again.
69.3 and 72.1% REL. Turn the ratio
37. Press the PEAK+ key then press the PEAK HOLD key. Switch the signal generator’s
HOLD. Turn off the peak hold function by pressing the PEAK+ key.
FM off.
The Measuring Receiver’s display should retain the largest value obtained after pressing PEAK
IF Level Check
38. Press the S (Shift) key then the IF LEVEL key (the (PM key). The Measuring Receiver should display between 99.9 and 100. lolo.
IF Frequency and LO Frequency
39. Set the signal generator to 100.000 MHz CW at
AUTOMATIC OPERATION key then key in
0 dBm. (Accurately set its frequency.) Press the
34.0 and press the SPCL key to display the frequency. The frequency displayed should be between 1.45 and 1.55 MHz.
IF
40. Key in 33.0 and press the SPCL key to display the LO frequency. The frequency displayed shoiild be between 101.45 and 101.55 MHz.
41. Key in 3.1 and press the SPCL key. (Special Function 3.1 switches the IF bandwidth back to
455 kHz.) The frequency displayed should be between 100.44 and 100.46 MHz.
Peak Tuned RF Level and RF High-Pass Filter Check
42. Set the signal generator to 5.25 MHz CW at 0 dBm. Key in 36.0 and press the SPCL key. The display should read between 0.500 and 2.000 -03 W (that is, between 0.5 and 2 mW).
43. Press the RATIO key. If the display is in
O/o
Key in 3.3 should display between key again. Key in to automatic.
3.0
-2 and
REL,
-8 dB REL. Turn press the LOG/LIN key to display dB off
REL. the ratio function by pressing the RATIO and press the SPCL key to return the RF high-pass and IF filter selection
Synchronous and Average Tuned RF Level Check
44. Set the signal generator for 20 MHz CW at 0 dBm. Press the S (Shift) key then the TUNED RF
LEVEL key (the RF POWER key) to measure the signal using the IF synchronous detector.
When the Measuring Receiver displays key. Adjust the signal generator’s level a so rending, press the MHz key. Press the CALIBRATE the Measuring Receiver displays 0.00 dBm.
3-55
Operation Model 8902A
45. Step down the signal generator’s level in 10 dB steps as listed in the following table. When the RECAL annunciator is displayed, press the CALIBRATE key while keeping the signal generator’s level constant. At each step the Measuring Receiver’s display should be within the limits indicated in the table.
Signal Generator
Output Level
(dew
-1
-30
0
-20
4 0
-50
-60
-70
-80
-90
-1 00
Minimum
-1 0.06
-20.12
-30.27
-40.48
-50.75
-61.08
-71
.ea
-81 .92
-92.43
-1 03.00
I
Maximum-
-9.94
-19.88
-29.73
-39.52
-49.25
-58.92
-68.53
-78.08
-87.57
-97.00
46. Return the level of the signal generator measure the signal using the generator’s level so
IF to 0.00 dBm. Key in 4.4 and press the SPCL key average detector. Press the CALIBRATE the Measuring Receiver displays 0.00 dBm. key. to
Set the signal
47. Step down the level of the signal generator, in 10 dB steps, using the same measurement limits as in the previous table.
Error Check
48. Set the signal generator to
AUTOMATIC OPERATION key then press the FM key. Press the PEAK+ key. After the
Measuring Receiver is tuned, press the RANGE key. The Measuring Receiver should display Error turn off the function.
200 MHz CW at 0.0 dBm. On the Measuring Receiver, press the
HOLD fi kHz
Press the RANGE HOLD key again to
49. Press the kHz key. Key in 2.1 and press the SPCL key. Set the signal generator’s FM on and adjust the peak deviation for 5 kHz (as read on its FM meter). The Measuring Receiver should display Error 04.
50. Key in 8.4 and press the SPCL key. The instrument should display Error 07.
High-Selectivity Level Check (Option Series 030)
51. Set the signal generator to 10 MHz CW at 0.0 dBm. On the Measuring Receiver, press the
Blue key then press the INSTR PRESET key (the AUTOMATIC OPERATION key) to preset the instrument. Key in 24.0 then press the SPCL key measurement. to initialize the high-selectivity level
52. Key in 24,l then press the SPCL key. Slowly fine tune the signal generator up and down until a maximum level is found. At that frequency key in 24.2 then press the SPCL key. (This establishes an IF level reference.)
53. Slowly fine tune the signal generator down until the Measurirtg Receiver displays the signal generator’s frequency.
-6.0 dB. Note
3-56
Model 8902A Operation
54. Slowly fine tune the signal generator up until the Measuring Receiver again displays between the limits shown in the following table for the option combination given.
-6.0 dB.
Subtract the displayed frequency from the frequency of step 53. The difference should be
Frequency Difference Limits (kHz)
Minimum
I
Maximum
Option Combination
032and 035
033 and 035
035 and 037
032 and 033
033 and 037
032 and 037 6.4 10.4
55. On the Measuring Receiver, press the Blue then press the SPCL key then press the INSTR PRESET key. Key in 24.0
56. Key in 24.3 then press the SPCL key. Slowly fine tune the signal generator up and down until a maximum level is found. At that frequency key in 24.4 then press the an IF level reference.)
SPCL key. (This establishes
57. Slowly fine tune the signal generator down until the Measuring Receiver displays the signal generator’s frequency.
-6.0 dB. Note
58. Slowly fine tune the signal generator up until the Measuring Receiver again displays -6.0 dB.
Note the signal generator’s frequency. Subtract the displayed frequency from the frequency of step 57. The difference should be between the limits shown in the following table for the option combination given.
~~ ~
Option Combination
032 and 037
033 and 037
035 and 037
032 and 033
032 and 035
033 and 035
Frequency Difference Limits (kHz)
Minimum Maximum
2.0 3.0
10.4
16.9
59. Fine tune the signal generator for a reading of 0.0 dB. Step down the signal generator’s level in 10 dB steps as listed in the following table. At each step the Measuring Receiver’s display should be within the limits indicated in the table.
3-57
Operation Model 8902A
Signal Generator
Output Level
(dBm)
-1 0
-20
-30
4 0
-50
-60
-70
-80
-90
Minimum
-11.0
-21
-31
.o
.O
.O
-51
-61
-71
-81
-91.0
.O
.O
.O
.O
Display 1 imits (dB)
Maximum
-9.0
-19.0
-29.0
-39.0
-49.0
-59.0
-69.0
-79.0
-89.0
External LO Check (Option Series 030)
60. Set the signal generator to 51.50 MHz CW at 0 dBm. Connect the signal generator’s output to the rear-panel
LO INPUT connector. Connect the sensor module’s input to CALIBRATION R F connector. (See Figure 3-1 1.)
POWER OUTPUT
50 OHM RF OUTPUT
61. On the Measuring Receiver, key in 45.16 and press the SPCL key then key in 23.1 SPCL and press the
SPCL key. (This turns the on the R F power calibrator and switches the LO to external.) Key in 50 then press
MHz key. The display should read between 48 and 52 MHz.
3-58
Model 8902A Operation
3-13.
BASIC FUNCTIONAL CHECKS
OF
THE HEWLETT-PACKARD INTERFACE
BUS (HP-IB)
Description
The following ten procedures check the Measuring Receiver's ability to process or send all of the applicable HP-IB messages described in paragraphs 3-1
Receiver's ability to recognize its HP-IB address is checked and all of the bus data, handshake and control lines except DI08 (the most significant data line which is not used by the Measuring
Receiver) are set to both their true and false states. These procedures do not check whether or not all
Measuring Receiver program codes are being properly interpreted and executed by the instrument; however, if
2 through 3-3 1. In addition, the Measuring the front panel operates as expected, the program codes, in all likelihood, will be correctly implemented.
The validity of these checks is based on the following assumptions:
The Measuring Receiver performs properly when operated via the front-panel keys (that
Receiver in paragraph 3-1 1. is, in local mode). This can be verified with the preceding Basic Fiinctional Checks of the Measuring e
The bus controller properly executes HP-IB operations.
The bus controller's HP-IB interface properly executes the HP-IB operations.
If the Measuring Receiver appears to fail any of these HP-IB checks, the validity of the above assumptions should be confirmed before attempting to service the instrument.
The select code of the controller's HP-IB interface is assumed to be 7. The address of the Measuring
Receiver is assumed to be 14 (its address as set at the factory). This select code-address combination
(that is, 714) is not necessary for these checks to be valid. However, the program lines presented here would have to be modified for any other combination.
These checks are intended to be as independent of each other as possible. Nevertheless, the first four checks should be performed in order before other checks are selected. Any special initialization or requirements for
; check are described at its beginning.
Initial Setup
The test setup is the same for all of the checks. Connect the Measuring Receiver to the bus controller via the HP-IB interface. connectors.
Do not connect any equipment to any of the Measuring Receiver's input
Equipment
HP-IB Controller or or..
................................................
HP-IB Interface..
..............
........
.HP
HP 9825A/982 I3A(General and Extended 1/0 ROM)
HP 9835A/98332A(I/O
HP 9845A(with HP-IB capability)
98034A (use "revised" version with 9835A and 9845A)
The HP 9825A uses HPL. HP 9835A and HP 9845A use BASIC. You use HP Series 200 Controllers which use BASIC. (Code differences exist bet.ween the
BASK used by the HP 9835A and HP 9845A and the BASK used by the
200 Controllers. These code differences are specified in the procedure.) can also
HP Series
3-59
Operation Model 8902A
Procedures
Using the table of of of the purpose the commands and then enter the commands appropriate to your controller exactly as described. Check that the instrument responds correctly.
Address Recognition Check
This check determines whether or not the Measuring Receiver recognizes when it is being addressed and when it is not. This check assumes only that the Measuring Receiver can
POWER the bus. Before beginning this check, set the Measuring Receiver’s switch to STBY, then to ON.
Description
Set the Remote Enable (REN) bus contro line false.
HPL
IC1 7
BASIC
LOCAL 7
Send the Measuring Receiver’s listen address. wrt 714 OUTPUT 714
Check that the Measuring Receiver’s
LISTEN annunciator is on.
Unaddress the Measuring Receiver by sending a different address
Check that the Measuring Receiver’s
LISTEN annunciator is turned off. wrt 715 OUTPUT 71 5
3-60
Model 8902A Operation
Remote/Local Messages and the v instrument to local control. This check assumes that the Measuring Receiver is able to both handshake and recognize its
Key Check
This check determines whether the Measuring Receiver proper1 switches remote control, from remote to local control, and whether the from key own address. Before beginning this check, select returns the
40.0 local to
SPCL.
Description
Send the Remote Message (by setting
Remote Enable, REN, true and addressing the Measuring Receiver to
Listen).
HPL rem 714
BASIC
REMOTE 714
Check that the Measuring Receiver’s
REMOTE and LISTEN annunciators are on.
Send the Local Message
Measuring Receiver to the Icl 714 LOCAL 714
Check that the Measuring Receiver’s
REMOTE annunciator is off but its
LISTEN annunciator is on.
Send the Remote message to the
Measuring Receiver.
Check that the Measuring Receiver’s
REMOTE and LISTEN annunciators are on. Press the LOCAL key on the
Measuring Receiver. Check that the
Measuring Receiver’s REMOTE annunciator is now off, but that its
LISTEN annunciator remains on. rem 714 REMOTE 714
3-6 1
Operation Model 8902A
Sending the Data Message Check (Data Output)
This check determines whether or not the Measuring Receiver properly issues Data messages when addressed to talk. This check assumes that the Measuring Receiver is able to handshake and recognize its own address. Before beginning this check, select 40.0 SPCL.
Description
Address the Measuring Receiver to talk and store its output data in variable V.
(The output is Error 96 since there is no signal at its INPUT.)
I
HPL red 714V
BASIC
ENTER 714;V
Display the value of V.
Check that the Measuring Receiver's
TALK annunciator is on. The controller's display should read 90000096000.00 (HP
9825A) or 90000096000 (HP 9835A and
9845A). dsp V PRINT V
Receiving the Data Message Check (Data Input)
This check determines whether or not the Measuring Receiver properly receives Data messages. The Data messages sent also cause the 7 least-significant HP-IB data lines to be placed in both their true and false states. This check assumes the Measuring Receiver is able to handshake, recognize its own address, and properly make the remote/local transitions.
Before beginning this check, select 40.0 SPCL.
Description
Send the first part of the Remote message (enabling the Measuring
Receiver to remote.
HPL rem 7
BASIC
REMOTE 7
Address the Measuring Receiver to listen
(complete the Remote message), then send a Data message (manually tuning the Measuring Receiver to 1 MHz. wrt 714,"lMZ" OUTPUT 714;"l MZ"
Check that the Measuring Receiver's
REMOTE and LISTEN annunciators are on. Check also that its 15 kHz LP FlLTEfi key light is on and the AUTO TUNING light is off.
3-62
Model 8902A Operation
Local Lockout and Clear Lockoutpet Local Messages Check
This check determines whether or not the Measuring Receiver properly receives the Local
Lockout message, disabling all front-panel keys. The check also determihes whether
SPCL. or not the Clear Lockout/Set Local message is properly received and executed by the Measuring
Receiver. This check assumes that the Measuring Receiver is able to handshake, recognize its own address, and properly make the remote/local transitions. Before beginning this check, select 40.0
Description
Send the first part of the Remote message (enabling the Measuring
Receiver to remote).
HPL rem 7
BASIC
REMOTE 7
Send the Local Lockout message
Address the Measuring Receiver to listen
(completing the Remote message).
Check that the Measuring Receiver’s
REMOTE and LISTEN annunciators are on. Press the Measuring Receiver’s
LOCAL key. Both its REMOTE and
LISTEN annunciators remain on.
I10 7 wrt 714
LOCAL LOCKOUT 7
OUTPUT 714
IC1
7 LOCAL 7 Send the Clear Lockout/Set Local message.
Check that the Measuring Receiver’s
REMOTE annunciator is off but its
LISTEN annunciator remains on.
3-63
Operation Model 8902A
Clear Message Check
This check determines whether or not the Measuring Receiver properly responds to the Clear message. This check assumes that the Measuring Receiver i s able to handshake, recognize its own address, make the remote/local changes. and receive Data messages. Before beginning this check, select 40.0 SPCL.
Send the first part to
Description of remote). the Remote message (enabling the Measuring
Receiver
HPL rem 7
BASIC
REMOTE 7
Address the Measuring Receiver to listen
(completing the Remote message). Then send a Data message that sets the
Measuring Receiver's tuning to manual. wrt 714,"MZ" OUTPUT 714;"MZ"
Check that the Measuring Receiver's
REMOTE and LISTEN annunciators are on and that the AUTO TUNING light is off.
Send the Clear message (setting the
Measuring Receiver's tune mode back to automatic).
Check that the Measuring Receiver's
REMOTE and LISTEN annunciators are on and that the AUTO TUNING light is on. clr 714 RESET 714
For Series 200
CLEAR 714
3-64
Model 8902A Operation
Abort Message Check
This check determines whether or not the Measuring Receiver becomes unaddressed when it receives the Abort message. This check assumes that the Measuring Receiver is able to handshake, recognize its own address, make the remote/local changes, and enter serial-poll mode. Before beginning this check, select 40.0 SPCL.
Description
Send the Remote message to the
Measuring Receiver.
HPL rem 714
7
714
~ BASIC
REMOTE
For Series
REMOTE
REMOTE
714
200
Check that the Measuring Receiver's
REMOTE and LISTEN annunciators are
Send the Abort message, unaddressing the Measuring Receiver. cli 7 ABORT10
For Series
ABORT
7
200
7
Check that the Measuring Receiver's
LISTEN annunciator is
HP 9835A and off. Note that the
9845A ABORT10 statement sends both the Abort message and the Local message. Thus, if the HP
9825A is being used, the Measuring
Receiver's REMOTE annunciator should remain on. If the HP 9835A or 9845A is being used, the Measuring Receiver's
REMOTE annunciator should turn off.
Send the Local message (HP 9825A) only IC1
7
Address the Measuring Receiver to talk and then store its output data in variable red 714,V
(The local message was already sent with the ABORT10 statement above.)
7
ENTER 714;V
Check that the Measuring Receiver's
LISTEN annunciator is off but that its
TALK annunciator is on.
Send the Abort message unaddressing the Measuring Receiver to talk. cli 7 ABORT10
For Series
ABORT
7
200
7
3-65
Operation
Abort Message Check (cont’d)
I
Descrintion ~~
Check that all the Measuring Receiver’s
HP-I6 annunciators are off.
Send the serial-poll-enable bus commanc
(SPE) to place the Measuring Receiver in seriai-poll mode.
~
HPL wti 0,7;wti 6,24
BASIC
SENDBUS 714;1,24
For Series 200
SEND 7;CMD”?5X”
&CHR$(24)
Model 8902A
On the Measuring Receiver, key in 61.3 and then press the SPCL key. The display should show 1.0. This indicates the Measuring Receiver is in serial-poll mode (indicated by the “1 “).
Send the Abort message, removing the
Measuring Receiver from serial-poll mode.
Check that the Measuring Receiver’s display shows 0.0. This indicates the
Measuring Receiver properly left serial-poll mode upon receiving the Abort message. cli 7 ABORT10 7
For Series 200
ABORT 7
3-66
Model 8902A Operation
Status Byte Message Check
This check determines whether or not the Measuring Receiver sends the Status Byte message in both able to the local and remote modes. handshake, recognize beginning this check, select its
40.0 SPCL.
This check assiimes that the Measuring Receiver is own address, and make the remote/local changes. Before
Description
Place the Measuring Receiver in serial-poll mode and address it to talk
(causing it to send the Status Byte message).
HPL rds (714) + V
BASIC
STATUS 714;V
For Series 200 v
=SPOLL(714)
Display the value of V.
Depending on the vintage of the HP-IB interface (HP 98034A) used, the
Measuring Receiver's TALK annunciator may be either or1 or off. The controller's display should read 0.00 (HP 9825A) or 0
(HP 9835A and HP 9845A).
Send the Remote message
Place the Measuring Receiver in serial-poll mode and address it to talk
(causing it to send the Status Byte message).
Display the value of V. dsp V rem 714 rds (714) + V dsp V
PRINT V
REMOTE 714
STATUS 714;V
For Series 200 v
=SPOLL(714)
PRINT V
Check that the Measuring Receiver's
REMOTE annunciator is on. Depending upon the vintage of the HP-IB interface
(HP 98034A) used, the Measuring
Heceiver's TALK annunciator may be either on or off. The controller's display should read 0.00 (HP 9825A) or 0 (HP
9835A and HP 9845A1.
3-67
Operation Model 8902A
Service Request Message Check
This check determines whether or not the Measuring Receiver can issue the Service Request message (set the SRQ bus control line true). This check assumes that the Measuring Receiver is able to handshake, recognize its own address, make the remote/local changes, and receive
Data messages. Before beginning this check, select 40.0 SPCL.
~~ Description
Send the first part of the Remote message (enabling the Measuring
Receiver to remote).
HPL rem 7
BASIC
REMOTE 7
Address the Measuring Receiver to listen
(completing the Remote message) then send a Data message (enabling a Service
Request to sent upon Instrument Error). wrt714, "22.4SP" OUTPUT
71 4;"22.4SP" wait 2000 WAIT 2000 Make the controller wait 2 seconds to allow time for the Measuring Receiver message. (This step is not necessary if sufficient time is allowed.)
Read the binary status of the controller's
HP-I6 interface and store the data in variable V (in this step,7 select code). is the interface's rds(7)
-+
V STATUS 7;V
For Series 200:
STATUS 7,7;V
Display the value of the SRQ bit. dsp"SRQ =",bit (7,V) PRINT "SRQ =";BIT
(V97)
For Series 200
"SRQ =";BIT(V,lO)
Check that the Measuring Receiver's
REMOTE, LISTEN, and SRQ annunciators are on and that the controller's display reads an SRQ value of 1, indicating the Measuring Receiver issued the Require Service message.
3-68
Model 8902A Operation
Trigger Message and Clear Key Triggering Check
This check determines whether or not the Measuring Receiver responds to the Trigger message and whether the
SPCL.
CLEAR key serves as a manual trigger in remote. This check assumes that the Measuring Receiver is able to handshake, recognize its own address, make the remote/local changes, and send and receive Data messages. Before beginning this check, select 40.0
Descriotion
Send the first part of the Remote message (enabling the Measuring
Receiver to remote).
HPL rem 7
BASIC
REMOTE 7 wrt 714,"Tl" OUTPUT 714;"Tl" Address the Measuring Receiver to listen
(completing the Remote message), then send a Data message (placing the
Measuring Receiver in Hold mode).
Send the Trigger message.
Address the Measuring Receiver to talk and store the data in variable V.
Display the value of V.
Check that both the Measuring
Receiver's REMOTE and TALK annunciators are on. The controller's display should read 90000096000.00 (HP
9825A) or 90000096000 (HP 9835A and
HP 9845A) or 9,00000 96E+10 (HP Series
200).
Address the Measuring Receiver to talk and store the data in variable V.
Check that the controller's "run" indicator is still on indicating that it has not received data from the Measuring
Receiver. Press the Measuring Receiver's
CLEAR key. The controller's "run" indicator should turn off. trg 7 red 714,V dsp V red 714.V
TRIGGER 7
ENTER 714;V
PRINT V
ENTER 7143
3-69
Model 8902A
Operation
3-1 4. DETAILED OPERATING NSTR UCTl ONS
Introduction to
the
Section
These Detailed Operating Instructions provide a complete operating reference
Receiver user. As for the Measuring an operating reference, this section contains all relevant information regarding operating the Measuring Receiver. (If you intend to operate the Measuring Receiver remotely, the
Rcmofc section contains information about how the Measuring Receiver interacts with a controller.)
This section is intended to be a reference document basic measurements using the HP 8902A for users who have already learned how
Giiidt? to
(part number make
08902-
90049) included with this documentation package. For your application, the Basic Operation and
Application Guide may be all you need
Instructions will enable you to make measurements. However, the Detailed Operating to use the full capabilities of the Measuring Receiver.
Section Organization
The section is organized into tabbed sections oriented toward specific measurement types. Each tabbed section contains all measurement capabilities and support functions involved in making that measurement type.
For example, the tabbed section, Modidation, contains all information about specific AM, FM, and
@M measurements as well as:
0 selecting an audio detector,
0
0 selecting an audio filter, selecting an audio range,
0
0 using the Modulation Output, and accounting for residual noise effects.
How To
Find Information About a Specific Measurement
Behind most tabs is a table of contents for that tabbed section. Use this table
Detailed Operating Instruction relevant to the measurement you are trying of contents to find the to make.
For example, if looking for information about making an FM measurement, find the tab “Modula- tion”. Find the table of contents behind that tab. Then look up the Detailed Operating Instruction,
FM. Turn to the page listed for that instruction. Within that Detailed Operating Instruction, you will find the following categories of information:
Functions lists all the Measuring Receiver functions to be discussed that pertain to FM.
Description introduces the FM measurement and any of the listed Functions,
Procedure provides specific instructions about making the FM measurement.
HP-IB lists all the Hewlett-Packard Interface Bus (HP-IB) codes relevant to making the FM measurement in remote operation.
Measurement Technique decribes the basic circuitry used to make the measurement. Sometimes, this information can provide an experienced user with to varied measurement situations. a basis for adapting the Measuring Receiver
Comments provide miscellaneous information that is not essential to the basic measurement but could be valuable to an experienced user attempting to use the Measuring Receiver situations not explicitely described in the “Procedure”. in measurement
3-71
Model 8902A Operation
RF
Power
and
Level
Contents
BROADBAND RF POWER
RF
RF
Power..
0
How to measure broadband RF power.
0
0
How to calibrate an RF power sensor (zero, calibrate, and save calibration) using the 1 mW reference.
How to enter the power sensor’s calibration factors into the instrument.
RF Power Calibration Factor Entry (HP-IB)
0
Level..
0
0
0
...............................................................................................
How to enter the power sensor’s calibration factors into the instrument using a program list in BASIC (for the the HP Series
How
Recorder Output..
How to
.............................................................. to measure (uncalibrated) broadband use the rear-panel RECORDER OUTPUT to monitor measurements via a dc voltmeter.
How to use the rear-panel RECORDER OUTPUT to improve the accuracy of measurements.
RF power
.3-75
.3-85
.3-89
.3-91
TUNED RF LEVEL
’Puned RF Level..
IF
IF
0
0
0
0
0 a
0
How
Output., to make low-level, tuned
How to select the
How
Level..
0
...............................................................................................
How
Peak ’Puned a
Attenuator Measurements
0
How
How
How to
IF detector (synchronous or average). select the optimum
RF Level measurements with Option 050.
................................................................................ to make relative, tuned
Selective Power Measurements (Option Series 030) to
........................................................................................
How to make Timed
How to calibrate the tuned
Level..
IF
RF
RF power measurements. detector averaging time.
RF level measurement when prompted by the UNCAL and RECAL
..................................................................................
...................................................... make selective, off-channel power or noise measurements (Option Series 030).
How to use the rear-panel IF OUTPUT to obtain the 455 kHz or 1.5 MHz IF signal.
.3-95
.3-109
.3-113
3- 115
3-119
.3-129
GENERAL LEVEL MEASUREMENT FUNCTIONS
External Attenuation
0
Remote Control
0
RF
....................................................................................
Switch.. ............................................................................
How to use the rear-panel REMOTE CONTROL connectors to control a remote RF switch similar to the way the RF switch is controlled in the HP 11722A Sensor Module.
.3- 1
.3-133
rev.24AUG8 7 3-73
Model 8902A Operation
RF Power
FUNCTIONS
RF POWER,
Function 37
Yo CAL FACTOR, ZERO, CALIBRATE, SAVE CAL, DISPLAY FREQ, Special
(Calibration Factors:RF Power)
DESCRIPTION
The Measuring Receiver can make calibrated measurements of RF and microwave power levels when used with a power sensor or sensor module.’ (Refer to
Spcvijcations for a list of compatible power sensors. Note that the Measuring Receiver automatically determines the type and sensitivity of the sensor.) Absolute level accuracy and sensitivity are determined by the particular power sensor selected and the SWR of the signal source.
Calibration. Specified measurement accuracy is ensured if calibration is performed with each power sensor. Calibration consists of four steps:
1. Entering the 1 mW, 50 MHz reference calibration factor and the frequency-dependent calibration factors from the power sensor’s calibration label.
Calibration factors (cal factors) are used frequency response relative to a printed on the power sensor or
1
Cal factors can be entered and stored in an internal table (Automatic Cal Factors) in the instrument’s non-volatile memory. The table measurements (after the Measuring Receiver has tuned the non-linear frequency response of the power sensor. If corresponds to the frequency being measured, the Measuring Receiver derives a cal factor through linear interpolation using the nearest calibration points in the table (on either side of the frequency being measured). Up entered (plus the reference cal factor). to to mW reference calibration made at
Power Reference Oscillator. The cal factors, including a reference cal factor, are usually sensor module. is compensate the external power sensor’s sixteen
50 MHz using the automatically accessed during R F power to the frequency) no to correct for entry in the table directly frequency/calibration-factor pairs can be
You can enter, review, and manually alter cal factors. Also, you can manually override the selection of automatic cal factors without altering the table.
2. Zeroing the power sensor.
The zeroing process cancels any inherent dc offset that may be present within the power sensor under zero power condition.
3. Configuring the Measuring Receiver to measure the power from the 1 mW RF power reference
(the 1 mW Power Reference Oscillator).
The internal 1 Power Reference Oscillator, used in extremely amplitude-stable
500, traceable
MHz
m W to
(voltage out vs.
RF power in).
R F power soiirce that has been set power calibration is an to 1 mW (0 dBm) into the National Bureau of Standards (NBS). This power reference enables the Measuring Receiver to precisely determine the sensitivity of the external power sensor at 50
4. Scaling subsequent power measurements to the 1 mW calibration.
In scaling, the Measuring Receiver equates the output from the power meter to 1 mW.
A scnsor modulc contains a powcr sensor path and a through path for RF mcasurcmcnts as wcll as an RF switch to switch between the two paths. Thc Measuring Rcceivcr controls the switching of the input signal depcnding on the measurement selected.
3-75
3-76
Operation Model 8902A
PROCEDURE
Determine Cal Factor Status. Determine the status of the calibration factors and enter new calibration factors if necessary. Connect the power sensor or sensor module to the Measuring
Receiver's SENSOR input. (The power sensor cable need not be connected time.)
1. Select calibration factors as described in steps a and b below. If step 4.
RF POWER. If Error 15 to the source at this is displayed, no calibration factors have been entered. Enter
Error 15 is not displayed, proceed to
2. Enter the reference cal factor (the reference cal factor is the cal factor for 50 MHz; all other cal factors are relative
37.3
O/o
SPCL, to it):
Example: Enter a reference cal factor of 98.5% into the Automatic Cal Factor table.
(program codes)
Code function
37.3
T 1-
Code
Function
I-
LOCAL
(keystrokes)
- f
7
l
3. Enter each frequency/cal-factor pair:
37.3 SPCL, frequency value (in MHz), cal-factor value, VOCAL FACTOR (Blue Key, MHz).
Repeat this step until all frequency/cal-factor pairs have been entered.
0
Disregard Error 15 if it is displayed during cal factor entry.
0
If an error is made during entry of any value, select CLEAR and immediately re-enter the correct value.
Example: Enter a cal factor of 99.00/0 at a frequency of 1 MHz.
(program codes)
C O D E 1 r r 1
(Blue uey1
FUNCTION
1
GAL FACTOR
Model 8902A Operation
4. Verifj.
% that sensor:
37.6 SPCL; the Automatic Cal-Factor table was entered correctly.
Recall the reference cal factor and compare the value to that on the label on the power sensor:
37.5 SPCL, % CAL FACTOR (Blue Key, MHz)
5. Recall each frequency/cal-factor pair and compare each value to its counterpart on the power
DISPLAY FREQ (Blue Key,
CAL FACTOR (Blue Key,
Repeat this step until
0
0
fi)
to display the frequency value,
MHz) frequency/cal-factor
Attempting to read beyond the end of the table results in Error 26. used in the entry (refer to step 1). to display the cal factor value. pairs have been verified.
To replace an existing cal-factor entry, enter the new cal factor at the frequency previously
0
To remove an existing cal factor from the table in memory, enter 0% as the cal factor frequency previously used in the entry (refer to step 1). at the
6. To re-enter the Automatic Cal Factor mode, select AUTOMATIC OPERATION, then reselect
RF POWER.
Zero the Sensor.
Ifthe instrument has just been turned on, allow at least a half-hour continuous op- eration. Connect the sensor between the Measuring Receiver’s SENSOR input and CALIBRATION
RF
POWER OUTPUT.
7. Select ZERO. Jf a power sensor is being used (rather than a sensor module) the CALIBRATE key light must be off for proper zeroing. (A sensor module has an internal switch that will automatically switch out any input signal.) After a few seconds, 0.0 00 W is displayed, then a measurement result of near zero power is displayed.
Configure the
1 mW RF
Power Reference
8. Select CALIBRATE. The instrument displays the power from the the last calibration scaling.
RF power reference using
Enable Calibration Scaling
9. Select SAVE CAL (Blue Key, CALIBRATE). Read 1.000 mW. The calibration scaling stays in effect until another SAVE CAL operation is done. Select CALIBRATE again to turn the calibrator (CALIBRATE key light om measurements will not range properly.)
.
CK
the calibrator is not turned off, the RF power
THE MEASURING IS
RF POWER.
(Note that when calibrating the Measuring Receiver over the CALBRATE (C1)
and
HP-IB, T3 settling time code between
SAVE CAL (SC) codes. For example: ClT3SC.)
Additional Recommendations:
0
Re-calibrate the sensor when ambient conditions change or approximately every eight hours.
0
Whenever the source frequency is changed, either select the new frequency manually (in MHz) or select FREQ to let the instrument automatically tune to the signal, then re-enter the RF Power measurement mode. Also, if the tuned frequency moves more that hi5 kHz from the frequency at which the power sensor reference was taken, the instrument must be retuned.
0
Use the table on the following page, ‘‘Summaqy of Special Function 37” for a quick overview of all the codes that manipulate the RF power cal factors.
3-77
Operation Model 8902A
37.2
Summary of Special Function 37
-
37.0 Selects the Automatic Cal Factor mode. This ables the Measuring Receiver to automatically se- lect cal
Sbecial Function Describtion
~~ en- factors based on those entered using Special
Function 37.3.
Selects the Manual Cal Factor Mode. This enables the user to override the automatic selection of cal factors.
Procedure :
To enter a manual cal factor, select:
37.1 SPCL,
Key, MHz) cal factor value, Oh CAL FACTOR (Blue
0
This mode with Automatic Operation.
0 is
Comments selected upon instrument power-up and
Can be keyed from any Measurement mode.
0
If no cal factor is entered, the Measuring Receiver uses the cal factor recalled last from the table as the manual entry.
0
The manual cal factor remains in effect when the
Measuring Receiver is retuned.
0
The automatic manual cal factor entries.
0
Can be keyed only after selecting RF POWER.
0
Can be cat factor table is not affected keyed from any Measurement mode. by any
37.3
37.4
Displays the status memory.
Procedures: cat factor value, of the cal factor mode
(0 =Automatic, 1 = Manual).
Prepares to enter a reference cal factor or a fre- quencyhl-factor pair into the appropriate table in
To enter the reference cal factor, select: 37.3 SPCL,
Oh CAL FACTOR (Blue Key, MHz).
To enter each frequencykal-factor pair, select:
37.3 SPCL, frequency value (in MHz), MHz key, cal factor value,
O/O
CAL FACTOR (Blue Key, MHz). (It's unnecessary to wait until the values are displayed be- fore continuing with subsequent entries.)
(See examDles in this section.)
Displays the number of entries in the table.
0
If an error is made during entry of any value, select
CLEAR and immediately re-enter the correct value.
0
To replace an existing cal factor entry, enter the new cal factor at the frequency previously used in the entry.
The Measuring Receiver will automatically save the entry in the correct order
0 in the table.
To remove an existing cal factor from the table in memory, enter 0% as the cal factor at the frequency previously used in the entry.
0
Can be keyed from any Measurement mode.
-
37.5
37.6
37.9
Prepares table. to recall the reference cal factor from the
Procedure:
To display the reference cat factor, select:
37.5 SPCL,
O/O
CAL FACTOR (Blue Key, MHz).
Prepares to recall the next frequencykal-factor pair from the table.
Procedure :
To display the frequency, select:
37.6 SPCL, DISPLAY FREQ (Blue Key, kHz).
To display the cal factor, select:
O/O
CAL FACTOR (Blue Key, MHz).
37.6 SPCL sequentially accesses frequencykal-factor pairs.
(See example in this section.)
Clears the table of cal factors from memory. table of calibration factors, use 37.3 SPCL.
To enter a manual cal factor, use 37.1 SPCL. To enter a new
0
The number of table entries displayed also includes the reference calibration factor.
0
0
Can be
This special function configures the Measuring Re- ceiver to cal factors with the reference cal factor from the table as the manual entry. To re-enter the
Automatic keved from anv Measurement mode. use manual
Cal Factor mode, select AUTOMATIC OPER-
ATION or 37.0 SPCL.
0
0
Can be keved only after selectina RF POWER.
The table in memory is accessed sequentially (the est frequency accessed first). To access the lowest low- fre- quency in the table, select 37.5 SPCL before selecting
37.6 SPCL.
0
This special function configures the Measuring Re- ceiver to use manual cal factors with the cal factor re- called last from the table as the manual entry. To re- enter the Automatic Cal Factor mode, select AUTO-
MATIC OPERATION, then reselect RF POWER.
An attempt to read beyond the end of the table results in Error 26.
0
Displays Error 15 if automatic cal factors were being used.
Can be keved from anv Measurement mode.
3-78
Model 8902A Operation
HP-18 PROGRAM
CODES
O/o
CAL FACTOR = C F
CALIBRATE on = C1
CALIBRATE
DISPLAY FREQ
CO
FR
HZ
HZ
LIN results = LN
LOG results = LG
MHz = MZ
RF POWER =
ZERO ZR
M4
SAVE CAL = SC
WATTS Units = WT
=
MEASUREMENT TECHNIQUE
The RF Power Measurement
The power sensor produces a small dc voltage which is proportional to the power dissipated in the sensor’s input load. The dc voltage is then converted to ac, amplified, and converted back to dc. The
Measuring Receiver’s internal dc voltmeter measures the voltage and displays the reading in terms of power.
Five ranges of amplification are used to encompass the power sensor’s wide dynamic range. Special
Function 10 permits manual selection of the five ranges: Range 1 (10.1 SPCL) has the most amplification (the most sensitivity), while Range 5 (10.5 SPCL) has the least amplification (the least sensitivity). The ranges are not specified in terms of absolute power because the sensor type determines the sensitivity.
The chopper in the power sensor converts the dc voltage (generated by the power sensing element) to a 220 Hz, chopped, ac signal. The ac signal is then amplified and rectified by a synchronous detector whose configuration alternates between with the chopper. (The 220 Hz Multivibrator is the source for both chopping signals.) The result is a rechopped, dc level proportional and noise. to a non-inverting and an inverting amplifier in step the dc output of the RF power sensing element of the power sensor. This chopping and rechopping method reduces the power meter’s susceptibility to dc drift
The dc level from the Synchronous Detector is filtered, to reduce noise then measured by the
Voltmeter. On the more sensitive ranges, filtering is increased to smooth out the large noise component on the signal and thus stabilize the displayed reading.
~
SENSOR WDULE
RF POWER
ELEYENl CHOPPER
,
-
RECE I VER
-
INPUT
OTHER TUNED
POWER HEATER
-,
-
VOLTMETER 7
OISPLAV
111 111 1-7 111 111 IZI IZI 111 111
I-II-II-I 1-1
,
I
I
3-79
Operation Model 8902A
RF Power Calibration
With the external power sensor properly connected to the Measuring Receiver, and the sensor’s
R F input connected the resistor indicates, to determining the sensor type. (See the Simplified Block Diagram of R F Power Calibration.) A switch at the input of the Voltmeter connects the power sensor’s resistor to the Voltmeter. The voltage across to the CALIBRATION RF POWER OUTPUT, calibration begins by first the Measuring Receiver, the type of power sensor being used. UNCAL and
RECAL annunciators are displayed if the sensor type differs from that used in a previous calibration.
When the ZERO key is pressed, the internal controller sends out a signal to switch out the RF input measurement. (The Measuring Receiver assumes that to the sensor module function is on, the 1 mW RF Power Reference stays on. If power sensor with no R F switch is connected to to the power sensor and directs the power meter zeroing digital-to-analog converter
OW to is at the power sensor input. make a power
If the Calibrate the calibrator output, the instrument will not zero properly.) The controller uses the
(DAC) in the power meter to output a dc voltage to cancel any d c offset that may be present at the power sensor. The zeroing process persists until the reading is zero, which may take several seconds to complete.
SENSOR MODULE
RF
,
I
I
I I
I
I
I r
- -
CIRCUITS
,-POWERMETER-\
ZEROING
- - - -
I
I
CALIBRATION
POWER REF
- - - -
DISPLAY
--1
I
I
- -
I i
SivnpliJicd Bloc-k Diagrum of
Ri:
Powr Cctlihralion
3-80
Model 890212 Operation
When CALIBRATE is selected, the power reference oscillator outputs a calibrated, 1 mW signal at
50 MHz. mW.
When SAVE CAL is selected, the controller equates the output from the power meter to 1
The calibration procedure allows the instrument to set the power-measurement transfer function so the displayed power correctly represents the actual power. This procedure can be visualized as a process that adjusts the intercept and slope of the sensor’s transfer function. The displayed power is given by the equation: paid = merct b
ZERO key sets the zero crossing (intercept), and the SAVE CAL key sets the gain (slope). (See the following figure.) The where;
Pdid is the Displayed Power,
Pact is the Actual Power, b is the zero crossing, and rn is the slope.
The calibration routine forces b = 0 and m = 1.
The following example shows the different responses that occur during calibration:
DISPLAYED
POWER calibration
ACTUAL POWER
. the ZERO key is pressed
(b=O)
3-8 1
Operation Model 8902A
Minor adjustments in the slope are made by the controller, based on the calibration factors, to correct for variations in the power sensor’s sensitivity due to frequency and mismatch.
COMMENTS
Reasons to Recalibrate.
Any time the power-sensor type is changed (for example, from an HP 8482A to an HP 8484A), and
RF POWER is selected, the Measuring Receiver displays the need for recalibration by lighting the
RECAL annunciator.
Any time power sensors of the same type are exchanged (for example, from one HP 11 722A to another), and RF POWER is selected, the Measuring Receiver DOES NOT recognize the need for recalibration. When in doubt about whether the calibration factors match the power sensor, use Special Function operating instruction.
37 to display the calibration factors as described in Pruwdiirr. sky #4 in this
Calibration information is retained in the Measuring Receiver’s non-volatile memory even when the
Measuring Receiver is disconnected from its power source.
Finer Resolution for dB Measurements
Special Function 32.1 enables a resolution of 0.001 dB. special function enables a resolution of 0.1 normally displayed resolution of through instrument power down.
1 Hz.
Hz
For audio frequency measurements, this for frequencies from 100 to 250 of Special Function 32.0 kHz instead of the or 32.1 is maintained
32.0 Power is displayed with the normal measurement resolution of 0.01 dB.
32.1 Power is displayed with a measurement resolution of 0.001 dB.
32.2 Displays 0 if the normal measurement resolution is enabled (32.0 SPCL) and displays 1 if a finer resolution is enabled (32.1).
Error 15.
Error 15 is displayed until all necessary cal factor entries are made. Two calibration factors must be available for the Measuring Receiver to make RF power measurements; factor, and a calibration factor at the signal frequency (entered manually from the Automatic Calibration Factor table). Also, if frequencies higher
15 is displayed. or
RF a or reference calibration derived automatically power measurements are attempted at lower than any frequency in the table, interpolation is not possible and Error
RF Frequency Range:
Resolution:
Calibration Factor Range:
Calibration Factor Resolution:
Maximum number of entriesjtable:
0-42 GHz RF Frequency
50 kHz
40- 1 20°/0
0.1%
17 for first table,
23 for second table
This spccial function is not available with firrnwarc date codes 234.1985 and below. (To display the Iirmwarc datc code. selcct
42.0 SPCL.) a ROM set that contains this spccial function. contact the ncarcst HP sales oficc.
3-82
Model 8902A Operation
A Second Cal-Factor Table for High-Frequency Measurements.
A second table having up to 22 pairs
Cunlrol
of frequency/cal-factor pairs (plus a reference cal factor), for more information about this mode.) is available for use with an external dow n-converter in the Frequency Offset mode. (Refer to Frclqiicwcy
0fl.S~~
When measuring power levels at high frequencies using module (such as the HP 11792A43, enter the reference cal factor as an entry in the table at
If this frequency/cal factor pair is a high-frequency power sensor or sensor less than the lowest frequcacy entered in the cal factor table (2
50 MHz. not entered. the instrument will not measure power at frequencies
GHz in the case of the HP 11792A).
Storing of Calibration Factor Tables.
The Store/Recall function cannot store a cal-factor table. However, t o avoid re-entering tables when frequent interchanging the second table for the second power sensor. Select 27.3
Oscillator (LO) value. (Refer to an external LO value.) of power sensors is necessary. either use Manual Calibration Factors,
OfIk1 Conlrol
SPCL and use 0 Hz as or use the external, Local
on page 3-255 for a procedure o n entering
These two Automatic Calibration Factor tables are retained in the instrument’s non-volatile memory for use in all subsequent I<F power measurements. Every time you use the second table, you must enter the external LO value.
User-Built Sensor Module.
Any compatible power sensor can be configured as a sensor module using an external RF switch wired to the remote control connectors on the Measuring Receiver’s rear panel. (Refer to Rcvnoki
Control R F Swi1c.h
Calibration Factor Resolution.
Calibration factors have a resolut.ion of 0. If%.
HP-IB: Interaction Between Calibration On and Zero.
CO aborts ZR, but when ZR is timed out. CI is not aborted.
HP-IB: Using Save Cal.
When calibrating the Measuring Receiver over HP-IS, use
Calibrate and Save Cal codes. For example:
C 1 T3SC
T3 settling time code between the
Input/Output Status.
MODULATlON OUTPUT/AUDIO INPUT is disabled during RF power measurements.
Relative Measurements.
If R F power is to be displayed relative to
RATIO key. (Refer to a reference. enter the value as a ratio reference using the
Ra/io
Frequency-Selective Level Measurements.
Use the Tuned R F Level function to make frequency-selective, absolute level measurements.
Source Impedance.
All measurement units assume a source impedance of 5052.
3-83
Operation Model 8902A
Power Measurements Alter Some Instrument States.
The instrument exits the automatic tuning mode when the R F Power function is selected. The
LO, and IF sections are inactive since power is being measured at the external sensor.
RF,
Reference Cal Factor Not Affected by Changing the Cal Factor Mode.
The SAVE CAL key, iised in conjunction with R F Power Calibration, scales subsequent measurements to the I mW RF
RF power
Power Reference and saves the Scaling Factor in non-volatile memory. Changing thc calibration factor mode does not change the reference calibration factor in use; for example. if the Measuring Receiver is calibrated from the manual cal factor mode and then the Automatic Cat Factor mode is selected, the instrument will continue to use the manually-entered reference calibration factor until another SAVE CAL operation is initiated from the Automatic
Calibration Factor mode.
Manual Cal Factors
Manual Cal Factors are not frequency selective: that is, as frequency is changed, the instrument will continue to use the calibration factor entered last. To obtain accurate measurements when using
Manual Cal Factors, a new calibration factor should be entered each time the frequency is changed.
The Manual Calibration Factor is not retained in the Measuring Receiver’s non-volatile memory and therefore, must be re-entered aRer AUTOMATIC OPERATION or INSTR PRESET is selected.
3-84
Model 8902A Opera ti on
RF
Example Program
3-2.
DESCRIPTION
The program list can be used series 200 to controller loaded with enter the
BASIC
RF
3.0. power calibration factor (cal factor) table using an
(Cal
RI:
HP factors are entered and stored in an internal table in the Measuring Receiver’s non-volatile memory-refer to Power.) It might be useful to use this program to enter the cal factor table rather than entering the cal factors manually.
You may want to modify this program. For example, to increase the number of cal factors that can be entered into the table, change program lines 220, 300, and 500 to specify
When running this program, softkeys are set up with the following labels: to 16 rather than to 10.
I
Address
1
Allows you to enter the HP-IB address of the Measuring Receiver.
Display Table
Displays the table of cal factors just entered. These are not necessarily the cal factors being used by the Measuring Receiver.
Enter Table
Enables you to enter individual cal factors into the cal factor table.
I
Read Cal
I
Displays the calibration factor table currently being used by the Measuring Receiver.
I
Send
I
Loads the calibration factor table into the Measuring Receiver that was entered with
I
Enter Table
I.
3-3.
PROCEDURE
Enter the program into an HP series 200 controller and connect the Measuring Receiver (via to the controller. Connect the power sensor or sensor module to the Measuring Receiver’s input. (The power sensor cable need not be connected to the source at this time.)
HP-IB)
SENSOR
Follow the steps below to use the program. (Note that words that have brackets around them like this:<RUN>, are keys on the controller. Words in boxes like this: (Address displayed on the controller’s screen.)
1, are softkeys
1. Select <Run>.
2. Select softkey,
I
Address
1 and enter the three-digit code that comprises the controller’s select code (for example, 7) and the Measuring Receiver’s address (for example, 14). (Display the
Measuring Receiver’s address by selecting BUS ADRS-Blue Key,
Receiver.) For these examples, you would type in:
LOCAL-on the Measuring
7 1 4 <ENTER>
3-85
Operation Model 8902A
3. If you want to display the cal factors currently being used by the measuring receiver, go to step 7.
4. Enter the new frequency/cal factor pairs by selecting
I
Enter Table
1. a. The controller will prompt:
"New Cal Factor for REF position cal factor?"
Enter the reference calibration factor. For example, enter 100% as:
1 0 0 <ENTER> b. The controller will prompt:
"New Frequency f o r number '1' cal factor?"
Enter the frequency (in MHz) for the first frequency/cal factor pair.
100 kHz as:
For example, enter
.
1 <ENTER> c. The controller will prompt:
"New Cal Factor for number ' ' frequency?"
Enter the cal factor for the first frequency/cal factor pair, for example, enter 99.09'0 as:
9 9 . 0 <ENTER> d. Continue entering the nine other frequency/cal factor pairs until the table is complete.
Note that selecting ENTER as a response to a prompt withour specifying a value will automatically select the value currently in the table.
5. Select I D i s p l a y Table
6. Select
I
Send
Receiver.
I to see the cal factors that you have entered.
1 to put those cal factors into the cal factor table in the Measuring
7. To display the cal factors currently used by the Measuring Receiver, select
I
Read C a l
The controller will query the Measuring Receiver and then display a list of frequency/cal-factor pairs currently in the table. The cal factors are listed in the format:
I.
50
.1
.3
1 .o
3.0
10
30
100
300
1000
2600
The first column ists each frequency (in of the frequency/cal factor pair. The second colunin lists each cal factor (in Yo) of the frequency/cal factor pair. (The first frequency/cal factor pair listed is
98.9
99.0
97.2
99.8
99.5
98.7
99.3
97.9
98.1
99.1
99.7
IHz) the reference cal factor that is measured at 50 be changed.) To enter new frequency/cal factor pairs, go to step
MHz.
4.
This frequency cannot
3-86
Model 8902A
3-3.
PROGRAM LISTING
10
20
30 Relabe1:CALL Clearscreen
40
50
60
70
80
90
100
110
150
160
170
180
190
200
210
220
230
240
250
Print:
PRINT Wse the softkeys below t o
260 Enter: OFF
270
280
290
300
3 10
320
330
340
350
360
370 Read:
380
390
400
4 10
420
430
440
4 50
460
470
480
490
500
519
520 Send:
530
COM
DIM
ON
ON
ON
ON
GOTO
CALL
/Cal,factor/ Freq(0: 16) ,Ca1(0:16) ,Hpib
A$[40I
Clearscreen
NEXT I
"Display Table"
"Enter Table"
.
GOTO
GOTO f*Sendfl GOTO Send
. I 9
ENTER, READ,
Enter or SEND c a l factors."
PRINT ll-----------------------------------------------------------ll
ON KEY 5
KEY
KEY
KEY
KEY
6
7
8
9
LABEL
LABEL
LABEL
LABEL
LABEL tfAddress" GOTO Address
'!Read Callt GOTO Read
120 Idle: DISP "Waiting f o r command
130 GOTO Idle
140 Address:DISP What
LINPUT Hpib$ is
Hpib=VAL (Hpib$)
Relabel the 8901B/8902A HP-IB addressft;
____________-__-____------
"New Frequency f o r number
INPUT Cal(1)
NEXT I
ENTER
EHTER
NEXT I
CAL
GOTO Idle
DISP
INPUT
Freq(O)=50
FOR
GOTO
CALL
' ;
"New Cal Fact or f o r number ' ; I ; ' frequency" ;
(0)=50
1=1 TO
OUTPUT
FACTORS"
OUTPJT Hpib; "41. SPM4TO"
OUTPUT Hpib
ENTER Hpib;Pairs
OUTPUT Hpib; "37.5SP CF"
ENTER
Freq
FOR
Freq(I)=Frequency/l .E+6
GOTn
OWPUT
I(
FOR 1-0 TO 10
PRINT Freq(1) ,Cal(I)
KEY
"New Cal Factor f o r
Cal(0)
1=1 TO 10
DISP
INPUT Freq(1)
DISP
Relabel
Clearscreen
;
Hpib; Cal(0)
Pairs
OUTPUT Hpib;I137.6SP
Hpib;Frequency
Hpib ;
Hpib; Cal(1)
IMAGE "37.3SP" ,4D. 2D, "CF"
REF
FR"
! Print out c a l factors. position c a l factor";
!
!
!
!
!
!
II
I ;
Set t o
Ref cal
'
RF c a l factor" ;
POWER mode.
Ask how many cal factors there are.
Enter the number of c a l factors.
Ask f o r reference c a l factor-50 MHz.
Enter reference c a l f a c t o r . i s always 50 MHz.
! Ask f o r next frequency.
! Enter next frequency.
! Divide by
!
!
Ask
1 million t o get MHz. f o r next cal f a c t o r
Enter next cal f a c t o r .
Operation
3-87
Operation Model 8902A
540
550
560
570
580
590
600
610
OUTPUT Hpib USING 530;Cal(O)
FOR Is1 TO 10
IMAGE
BEEP
I tt37.3SP11
! Send reference cal factor.
OUTPUT Hpib USING 560;Freq(I),Cal(I)
NEXT
GOT0 Relabel
END
620 ! !
630 C1earscreen:SUB Clearscreen
640 !!
650
660
670
OUTPUT 1 USING
DISP
SUBEND ll#,@tt
! sending new cal factors.
3-88
I
Model 8902A Operation
RF
Level
FUNCTIONS
Special Function 35 (RF Level)
DESCRIPTION
The RF Level function enables the Measuring Receiver to meastire and display the peak, R F power.
R F level measurements are initiated with Special Function 35 or there is no sensor at the Measuring Receiver’s SENSOR input. with the R F POWER key when
R F level measurements are an external power sensor as not calibrated, so with R F Power measurements. (Refer to
RF
measurements made with
Power
PROCEDURE
To make a broadband R F power measurement with an R F cable connected from the signal source to RF INPUT (rather than a power sensor connection), select R F POWER.
To make the measurement with the power sensor connected, key in 35.0 SPCL.
HP-IB PROGRAM CODES
LIN = LN
LOG = LG
R F POWER = M4
SPCL = SP
MEASUREMENT TECHNIQUE
The broadband RF power at R F INPUT is detected by an R F peak detector. The output of the detector is measured and displayed.
When RF Level is selected,
SWR. Any manual setting the Measuring Receiver sets its R F input attenuation to 50 dB to minimize of RF input attenuation/gain (Special Function 1) is overridden.
3-89
Operation Model 8902A
OVERPOWER t
I
A -
TO OTHER
MEASUREMENT CIRCUITS
I
RF Lcvd
Measimmcnf Block Diagram
COMMENTS
Input/Output Status.
MODULATION OUTPUT/AUDIO INPUT is turned off during this measurement. However, AM
OUTPUT and FM OUTPUT (rear panel) remain active but uncalibrated. The tuning instrument remains unchanged. of the
Relative Measurements.
If RF level is to be displayed relative to
RATIO key. (Refer a reference, enter the value as a ratio reference using the to Ralio
Measuring RF Level on Signals with AM.
If the RF input signal has AM, the peak envelope power is measured.
Previous Input High-Pass Filter Selection.
The input high-pass filter (Special Function 3) remains inserted if previously selected.
Error 06.
The maximum allowable input level is 1 W into relay to open and the display to show Error any measurement key.
50R. reset the relay, remove the input signal and select
3-90
Model 8902A Operation
Recorder Output
FUNCTIONS
Special Functions 49 and 50 (Display Internal Voltages)
Voltages grealer fhan 10 Vdc applied to fhe RECORDER cairsc damagc .to ihc infcrnal cirmifry.
OUTPUT
corrld
DESCRIPTION
The RECORDER OUTPUT makes available the voltage that is being read by the instrument’s internal dc voltmeter. Accuracy can be improved for some measurements by connecting to the
RECORDER OUTPUT a dc voltmeter that has greater accuracy, linearity, offset, and resolution than the internal voltmeter. This procedure significantly improves the accuracy of the R F Power and Tuned R F Level measurements.
In normal operation, the internal voltmeter is constantly taking readings at various points throughout the instrument as part of its measurement process. The signal at the RECORDER OUTPUT then, is a random series of pulses of varying level. When Special Function 49 or 50 is not enabled, the
RECORDER OUTPUT is useful mostly as a troubleshooting aid.
However, Special Functions 49 and 50 can set the internal voltmeter to suspend normal operation and to measure one input only. The voltmeter’s input is displayed and delivered to the RECORDER
OUTPUT. This feature has two general applications: data logging (for example on a stripchart recorder) and accuracy improvement.
Special Functions 49 and 50 are Service Special Functions which are documented more fully in
Sccfion
(I of the Stwicc Manrid. Use the following partial list of Special Functions to “freeze” the instrument (no ranging, retuning, etc.) and deliver to the RECORDER OUTPUT a dc voltage equal to the level being read by the internal dc voltmeter:
3-9 1
~
Operation Model 8902A
3-92
Special
Function
49.00 SPCL
49.01 SPCL
49.02 SPCL
49.03 SPCL
49.04 SPCL
49.05 SPCL
49.06 SPCL
49.07 SPCL
49.09 SPCL
49.OA SPCL*
49.OB SPCL*
49.OD SPCL*
49.OE SPCL*
49.OF SPCL*
50.06 SPCL
50.07 SPCL
Measurement Voltage Displayed and
Delivered to RECORDER OUTPUT
Ground
RF Peak Detector Ground
RF Peak Detector (divide by 3)
RF Peak Detector x10 AM Calibrator
XI AM Calibrator
Audio Range Detector
RMS-to-DC Converter
Audio Average Detector
Audio Peak Detector
IF Average Detector
IF Peak Detector
ALC Current
RF Average PoweT**
IF Synchronous Detector(without DC-to-RMS
Converter)
IF Synchronous Detector(with DC-to-RMS
Converter)
* A is Gold Shift, 0 B is Gold Shift, 1; D is Gold Shift, 3; E is Gold Shift, 4; and F is
Gold Shift, 5; “B” is displayed as “b”
“X” in place of the Gold Shift Key. and “D’ as “d”. For
**
For this Special Function, preceed with Special Function 0.212. Ignore the display after keying in Special Function 0.212.
PROCEDURE
To do analog data logging with the Measuring Receiver:
1. Connect the logging device to the RECORDER OUTPUT.
2. Select the desired measurement. Since the instrument will not be safeguarded (no ranging, retuning, error messages, etc.), be sure the instrument is set up properly for worst-case expected signal conditions.
3. Key in the appropriate special function using the preceeding table as a guide.
NOTE
The mtmiircmcn( iinif is volts. Rwdings o j 4 arc’ no1 vulid. meaasitremcnts satisfv calihraiion rcyiiiremcn fs .rincc thc mca.wrod voltugc is directly proportional to the normal nwasitrt~rntwi display. For exampkc, normal FA4 reading is 35.0 kHz,
N in c~xccss
RI:CORDER
OUTPUT
qf
A4o.w
if‘
u
3.50, iising
Special Firnction 49.0A, corrcqxh’s to 35.0 kHz pcwk FA4 dcviution.
For data logging RF power, use the following procedure.
To increase accuracy of RF Power measurements:
1. Connect an accurate dc voltmeter to the RECORDER OUTPUT. The voltmeter should have at least a 1 Mil input impedance. Let the instruments warm up for at least one-half hour.
2. Connect a compatible power sensor or sensor module to the SENSOR input. Connect the power sensor’s input to the CALIBRATION RF POWER OUTPUT.
3. Select RF POWER, then ZERO. Wait for the ZERO key light to go out.
Model 8902A Operation
4.
(The “S” in the Special Function code is the Gold Shift key. After keying in displayed.)
S 5, an “F” is
Special Function
10.3,
10.2, 0.212,
10.1, 0.212,
49.0
S
S
5
5
Variable Name vz3, vz4, v z 5 v z 2
V z l
Voltmeter Reading in V
NOTE
For best accirracy on the
(Vzl) shoirld easily done
via
a
most
scwsitivt> range (range programmable vollmett>r irndcr l), the zero
HP-113
cycks. control.
This
voltagt> is
mosf
5. Key in 10.0 SPCL then CALIBRATE. Key in vc
=
S, 5, SPCL. Record the voltmeter reading
(Vc). Select SAVE CAL (Blue Key and CALIBRATE key) to calibrate the Measuring Receiver’s display. The display should read 1 mW.
49.0,
V
6. Select SPCL twice. Record the least-significant digit (the tenth digit) on the display (Rc). (This digit indicates the RF Power range for the calibration.)
Rc =
7. Select AUTOMATIC OPERATION. Select CALIBRATE to turn
Mode. off the Recorder Output
8. Connect the signal source to the power sensor’s input. Allow the Measuring Receiver to make a normal RF power measurement.
9. Key in 0.212 SPCL. Key in vp
S 5
= and record the voltmeter reading
V
(Vp).
10. Select SPCL twice. Record the least-significant digit (the tenth digit) on the display digit indicates the RF Power range.)
Rp =
11. Compute the RF power (P, mW) from the following formula: p = -
IO(Rp - Rc) where
CFc is the reference (50 MHz) calibration factor from the chart on the power sensor;
CFp is the calibration factor at the signal frequency from the chart on the power sensor;
VzRc is the voltage from step 4 Rc;
VzRp is the voltage from step 4 range Rp.
12. Begin subsequent RF power measurements at step 2 otherwise, begin at step 9. as long as the results of step 4
3-93
Operation Model 8902A
COMMENTS
For
further
details on Special Functions 49 and 50, refer to Service Special Functions in SccVion 8.
Internal Voltmeter Offset.
The RF power circuits do not zero to OV. Instead they “zero” to between subtracts this offset from subsequent power readings.
0.W and 0.8V which permits the internal dc voltmeter to operate over its most linear range. The internal controller
3-94
Model 8902A Operation
Tuned RF Level
FUNCTIONS
Synchronoiis and Average TUNED RF LEVEL, CALIBRATE, SET REF, Special Functions
39 (Display and Enter Tuned RF Level Calibration Factors), Special Function
Selection and Display Averaging)
4 (Tuned
38 and
RF Level
DESCRIPTION
The Measuring Receiver can accurately measure the absolute or relative level of extremely low- level, continuous wave (CW), RF signals. At each measurement frequency, the instrument must be calibrated to correct for frequency-dependent measurement variations. Calibration over the full dynamic range requires calibration at three different levels. The calibration remains valid for any
CW signal at that frequency
f5%
(or &IO MHz, whichever is smaller).
Requirements for the Tuned RF Level Measurement
Before an absolute Tuned R F Level measurement can be made, the following 3 requirements must be met. Before a relative Tuned RF Level measurement can be made, only requirements 2 and must be met (since no power sensor is used during relative measurements):
3
1. The RF Power measurement must be calibrated.
The accuracy of the Tuned detail in R F Power
RF Level measurement depends on a calibrated
RF Power measurement made with an external power sensor. (RF Power calibration is discussed in
2. The Measuring Receiver must be properly tuned.
The Measuring Receiver can be tuned manually or automatically. When manually tuning, enter a frequency value into the Measuring Receiver within
12.5 f50
MHz. kHz for frequencies 2 f2.5 kHz for frequencies within k 2 kHz for frequencies between 2.5 MHz and 10 MHz, and within
MHz. When automatically tuning, select FREQ and ensure that the initial input signal level is greater than -20 dBm. (RF Freqircncy Tuning
3-141 has more details on the different types of tuning available.)
3. The Tuned RF Level calibration factors for the frequency being measured must be in place.
To calibrate the Tuned RF Level measurement (and allow the Measuring Receiver to create calibration factors), step the input signal down and select the CALIBRATE key
(while keeping the signal level constant) each time RECAL is displayed. Each time the
CALIBRATE key is pressed, the Measuring Receiver creates a calibration factor from comparison of the two measured levels. a
Up to three calibration factors will be created. These three Tuned RF Level calibration factors remain valid regardless of power level as long as the signal frequency is the same.
Each individual calibration factor is tagged with the frequency at which it is valid, and the status of the first three filters in the front of the instrument (Special Function
Special Functions 1.0 and becomes invalid.
1.9). If
3 and any of these conditions change, the calibration factor
The Tuned RF Level measurement must be recalibrated if the frequency is changed.
Tuned RF Level calibration can be performed during the actual measurement. Tuned
R F Level calibration factors can be entered (using the Store/Recall function or Special
Functions 38 and 39) if you have measured that frequency before. rcv. I h1.4 Y86 3-95
Operation Model 8902A
Sensitivity vs. Selectivity; Special Function 4
Tuned R F level measurements can be made with tracking IF
IF synchronous detector is more sensitive measures to a A5
SPCL) synchronous detector
- of
IF on
(4.0
(it measures of to two internal detectors:
- a
(4.4 SPCL). signal drift and residual FM than the IF average detector. When average detector power-up.
(4.4
127
The dBm) than the average detector (it dBm). Although the IF synchronous detector can track a drifting input signal over kHz range, it is less tolerant
SPCL). The IF synchronous detector (4.0
If the signal drifts too much even for the IF average detector, use track mode tuning with this detector
(not available with the IF synchronous detector). Refer to
Comments,
RF Level Measurements Using Track Mode Tuning" on page 3-105.
"Special Function 32.9; Tuned
Storing Calibration Factors for the Tuned RF Level Measurement
Calibration at every frequency of interest is time consuming. So, when making repetitive Tuned
RF Level measurements at many different frequencies, use the Store/Recall function to recall the calibration factor for each frequency of eight frequencies are to be measured, use Special Functions 38 and 39 to display and enter the calibration factors for each frequency special fbnctions. of interest. A procedure below explains how to use these
PROCEDURE
The following procedures are provided in this Procediire section:
1. Calibration for Absolute Measurements a. Using a Sensor Module3: Calibrating a Tuned RF Level Measurement. b. Using a Power Sensor: Calibrating a Tuned R F Level Measurement.
2. Calibration for Relative Measurements.
3. Using Special Function 4
4. Using Special Functions 38 and 39 to Display and Enter Tuned RF Level Calibration Factors. a. Special Function 38; Display Tuned R F Level Calibration Factors. b. Special Function 39; Enter Tuned RF Level Calibration Factors. c. Considerations When Using Special Functions 38.
CALIBRATION FOR ABSOLUTE MEASUREMENTS
Before attempting one of these procedures, be sure that I ) the RF Power measurement is calibrated,
2) the input signal is within the range required by the power sensor but not greater than 0 dBm
(for example, 0 to -20 dBm for the HP 11722A). and 3) the Measuring Receiver is properly tuned.
The following procedures enable the Measuring Receiver to obtain its calibration factors frequency being measured. for the
Two procedures are provided. If a sensor module is used, use the first procedure. If a power sensor only is used, use the second procedure.
A sensor module contains a power scnsor path and a through path for RF measurements as well as an RF switch to switch between the two paths. The Mcasuring Reccivcr controls the switching of the input signal depending on the measurement selcctcd. Examplcs of sensor modules arc Ihc HP 1 1722A and the HP 1 1792A.
3-96
Model 8902A Operation
Using a Sensor Module: Calibrating a Tuned RF Level Measurement
1. Select INSTR PRESET (Blue Key, AUTOMATIC OPERATION). (Since the Frequency measurement is automatically selected with INSTR PRESET, the instrument tunes to the signal at this time.)
2. Connect the sensor module to the R F source. The signal level should be greater than -20 dBm.
3. If the measurement can be made and the display is stable, go to the next step. (You will be using the IF synchronous detector.) If the input signal is noisy or has display jitter, select 4.4
SPCL. (You will be using the IF average detector.) The Measuring Receiver will not be able to make a measurement on a signal that has too much noise.
4. Select TUNED RF LEVEL (S, module has not been changed since the last calibration, go to step 7.) to be displayed.
Observe the RECAL annunciator in the display. (If RECALl is not displayed and the sensor
5. the LOG/LIN key enables the Measuring Receiver to display the result in either logarithmic or linear units. If desired, select LOG/LIN to change the displayed units.
6. Do not change the input signal while pressing the CALIBRATE key to enable the Measuring
Receiver to create a calibration factor for the first range. Wait for the CALIBRATE light to go out before stepping the input signal further.
7. Tuned RF level measurements can now be made, but as the signal level is stepped down its full range, the RECAL annunciator will be displayed up to two more times when recalibration is required. (When the RECAL annunciator lights, do not change the source level.) Select
CALIBRATE. Then wait until the light in the CALIBRATE key goes out before stepping the input signal further. Selecting the CALIBRATE key enables the Measuring Receiver to create a second and thired calibration factor.
(If the RECAL annunciator is no longer displayed, but the UNCAL annunciator is displayed, re-adjust the source level until the RECAL annunciator lights, then select CALIBRATE.)
Using a Power Sensor: Calibrating a Tuned RF Level Measurement
1. Select INSTR PRESET (Blue Key, AUTOMATIC OPERATION).
2. Connect a power sensor between the output of the RF source and the SENSOR input of the
Measuring Receiver. Input a signal with an amplitude value within the range of the power sensor.
3. Manually tune the Measuring Reveiver by entering the frequency of the R F source into the
Measuring Receiver. The display should read ‘‘- -”.
4. Select AUTO TUNING (Blue Key, TRACK MODE). The display will again read
5. Selcet TUNED RF LEVEL (S,
“-
6. Select CALIBRATE. Again wait for the
“-
-”.
-”.
“-
-”.
7. Disconnect the power sensor from the signal source. Connect the signal source to the Measuring
Receiver’s RF INPUT. Wait for the CALIBRATE key to go out and a valid measurement result to be displayed.
8. If the measurement can be made and the display is stable, go the IF synchronous detector.) If the input. signal is noisy or has display jitter, select 4.4 SPCL.
(You will be using the IF a measurement on a signal that has too much noise. to the next step. (You will be using average detector.) The Measuring Receiver will not be able to make rcv.30SEPT86 3-97
Operation Model 8902A
NOTE
If a valid mcusirrcmeiif rwdt is
nof
Rcccivcr again by cnlcring fhc jrcqircncy of fhc
RF
soirrcc into fhe Mtasuring
Receiver. IJ'maniraNy tuning ftis signal docs no1 display u valid mcasirremenf rcwlt, start thc procediire jkom fhe beginning.
9. The LOG/LIN key enables the Measuring Receiver to display the result in either logarithmic or linear units. If desired, select LOG/LIN to change the displayed units.
10. Tuned R F level measurements can now be made, but as the signal level is stepped down its full range, the RECAL annunciator will be displayed up to two more times when recalibration is required. When the RECAL annunciator lights, hold the source level steady, select CALIBRATE, and wait until the light in the CALIBRATE key goes out. Selecting the
CALIBRATE key enables the Measuring Receiver to create a second and third calibration factor.
(If the RECAL annunciator is no longer displayed, but the UNCAL annunciator is displayed, re-adjust the source level until the RECAL annunciator lights, then select CALIBRATE.)
CALIBRATION FOR RELATIVE MEASUREMENTS
Even though no power sensor is used, the Measuring Receiver still makes a reference measurement
(the value you set to be 0 dB) and calibrates subsequent ranges to that value. Use the following procedure for relative Tuned RF Level measurements:
1. Select INSTR PRESET (Blue Key, AUTOMATIC OPERATION). (Since the Frequency measurement is automatically selected with INSTR PRESET, the instrument tunes at this time.) to the signal
2. Connect an RF cable between the output of the RF source and the R F INPUT of the Measuring
Receiver. The signal level should be greater than -20 dBm.
3. If the input signal is stable, go to the next step.
If the input signal is noisy detector.)
(You will be using the IF synchronous detector.) or has display jitter, select 4.4 SPCL. (You will be using the IF average
4. Select TUNED RF LEVEL (S, RF POWER); wait for the uncalibrated display.
5. Tuned RF level measurements can now be made, but as the signal level is stepped down its fiill range, the RECAL annunciator will be displayed up to two more times when recalibration is required. When the RECAL annunciator lights, hold the source level steady, select CALIBRATE, and wait until the light in the CALIBRATE key goes out. Selecting the
CALIBRATE key enables the Measuring Receiver factor. to create a second and third calibration
(If the RECAL annunciator is no longer displnyed, but the UNCAL annunciator is displayed, re-adjust the source level until the RECAL annunciator lights, then select CALIBRATE.)
6. Set the RF level of the source to the level that is to be used as a reference. (Select the LOG/LIN key to change the display to the preferred display of Yo or dB.)
7. Select SET REF (Blue Key. ZERO). The display should read approximately
Subsequent measurements will be made relative to this level.
100°/o or 0 dB.
Morc information abouf rclativc Tuncd RF Lcvcl mcasurcmcnts can bc found in Atrmtifnror. Mmwr-twwnrs.
3-98
Model 8902A Operation
USING SPECIAL FUNCTION 4 TO SELECT THE IF DETECTOR
Special Functions 4.0 through 4.3 select the
4.7 the IF average detector.
IF synchronous detector. Special Functions 4.4 through
Special Functions 4.1 through 4.3 and 4.5 through 4.7 enable manual selection of the measurement display averaging time for each detector. The Measuring Receiver automatically selects these if Special
F'unction 4.0 or 4.4 is selected. It is usually unnecessary to manually select these times. (Refer to
Cornments,"Special Function 4 Also Controls Selection of Measurement Display Averaging".)
To select the
IF
synchronous detector, select
INSTRUMENT
4.0 SPCL. (This detector is
PRESET or AUTOMATIC OPERATION is selected.) selected on power-up or after
To select the IF average detector, select 4.4 SPCL.
To manually select the display averaging time refer
$election of Measurement Display Averaging". to Comments, "Special Function 4
Also
Controls
MAKING TUNED RF LEVEL MEASUREMENTS WITH OPTION 050
Instruments equipped with Option f0.014 dB calibrated f0.005
-120 dB the National Bureau of per 10 dB
050, step
Standards. for
Increased Power Measurement Accuracy, provide tuned f0.005 dB for absolute power measurements, and relative power measurements. These instruments have been dBm in compliance with dl3 per 10
MIL-STD-45662 using calibration standards
RF traceable to
Requirements for Option 050 Measurements. The accuracy specifications provided by Option 050 are warranted when using an HP synthesized signal source with less than 100 Hz peak residual FM measured in a 3 kHz post-detection bandwidth over a 30 second period. This allows the HP 8902A to use its narrow band IF synchronous detector.
Procedure for Making Option 050 Measurements.
1. Select Special finction 32.1 to increase the HP 8902A's display resolution to 0.001.
2. Select Special E'unction 4.1 to increase the averaging time to 10 seconds. (The increased averaging minimizes any digit flicker.)
3.
4.
Adjust the source level reference within f0.003 dB
-10 dBm and 0 dBm for absolute measurements, or set the for relative power measurements.
Perform the calibration procedures described in this section for the type of l'bned measurement you wish to make (absolute or relative).
RF
Level
Condiderations When Making Option 050 Measurements
Making Relative Level Measurements. performing the initial tuned starting your relative measurements.
The closer the reference source level is set to 0 dBm when
RF level calibration the greater your calibration certainty will be when
To achieve the greatest resolution, adjust the source level to the top of the
Vrms to optimize measurement resolution.
IF synchronous detector's range. To do this, select the Tuned RF Level measurement and then key in Special finction 50.05 (or
48.0). The HP 8902A will display the rms voltage level at the detector. Increase the voltage level to approximately 3
Residual Noise Level. level range.
The residual noise level of the HP 8902A increases in its lowest tuned RF rev.25AUG87 3-99
Operation Model 8902A
Minimizing Mismatch Uncertainty. mismatch uncertainty. A 10 pad positioned at the HP 8902A’s input and a 10 dB pad at the source’s output can help minimize mismatch uncertainty. Also, using well shielded cables can help reduce leakage.
USING SPECIAL FUNCTIONS 38 AND 39 TO DISPLAY AND ENTER TUNED RF LEVEL CALIBRA-
TION FACTORS
These functions are especially useful in remote operation when making repetitive Tuned RF Level measurements at many different frequencies. After a measurement is calibrated, you can display the calibration factors for that frequency using Special Function 38. These values can then be re-entered using Special Fbnction 39. When operating the instrument remotely, measurement time is decreased when it is not necessary to perform calibration. (Note: if the number of test frequencies is less than or equal to eight, consider using the Store/Recall function.)
To display and then re-use mned RF Level calibration factors, perform calibration at the frequency of interest; read the calibration factors using Special Function 38 (and record the values somewhere; for example, in a test program).
Then re-enter the calibration factors using Special Function 39 before making measurements at that frequency. (Before using Special F’unction 39 as calibrated at before.)
, is tuned to the same frequency
Special Function 38; Display Tuned RF Level Calibration Factors.
38.1 Display the calibration factor for Range #1.
38.2 Display the calibration factor for Range #2.
38.3 Display the calibration factor for Range #3.
38.45 Display the SET REF reference calibration value. (This value is displayed with a maximum of eight digits and a resolution of 0.01%.)
To display Tuned RF Level calibration factors: a. Select the TUNED RF LEVEL mode. b. Perform calibration for either absolute of relative mned RF Level measurements as described in the previous paragraphs. c. Select 38.N SPCL (where N is the desired suffix) d. Select % CAL FACTOR (Blue Key, MHz). e. Record the displayed value.
This special function is not available with firmware date codes 234.1985 and below
42.0 SPCL.) To order a
(To date code, select
ROM set that contains this special function, contact the nearest HP sales office.
3-100 rev.25AUG87
Model 8902A Operation
Special Function 39; Enter Tuned RF Level Calibration Factors.
39.1 Enter the calibration factor for Range #l.
39.2 Enter the calibration factor for Range #2.
39.3 Enter the calibration factor for Range #3.
39.46 Enter the SET REF calbration reference vale.
39.9 Clear all calibration factors.
RF Level calibration factors: a. Select the TUNED RF LEVEL mode. b. Select 39.N SPCL (when N is the desired
suffix).
The input signal level will be displayed. c. Key in the desired calibration factor value (for example, 120). d. Select 7% CAL FACTOR (Blue key, MHz).
Considerations When Using Special Functions 38 and 39.
0
Since different Tuned used SPCL or 4.4
RF Level calibration factors are created depending on the
SPCL), the first calibration factor (38.1
IF detector being re-entering the first calibration factor (391 SPCL). The second and third calibration factors do not depend on the IF’ detector being used. (for more information about this consideration, refer to Comments, SPCL, 4.4 SPCL, and SET REF affect the First Calibration”)
0
The state of Special Function 3 must remain the same when re-entering Timed calibration factors.
RF Level
0
The state of Special Function 1.0 or 1.9 must remain the same when re-entering
Levelcalibration factors.
%ed
RF
EXAMPLE
To enter a mned RF Level Calibration Factor of 120 7% for the RF power range 1:
(program codes)
Measurement
Code
S4 39.1
T
Function
$, ti
This
42.0 special function is not available with firmware
ROM date codes 234.1985 and below. (To display the firmware set that contains this special function, contact the nearest HP sales office. date code, select rev.25A
UG87
3-100.1
Model 8902A
HP-IS PROGRAM CODES
CALIBRATE on =
CALIBRATE off =
C1
CO
YO CAL FACTOR = C F
LIN results = LN
LOG results = LG
TUNED RF LEVEL = S4
VOLTS units = VL mV units = MV pV units = UV
WATTS units = WT
Operation
INDICATIONS
During routine measurement:
When TUNED R F LEVEL is selected, the following responses are displayed: four dashes to indicate the signal has been found, then six dashes tuning to the signal, then four again no signal can be found.
(-
- -
-)
(-
- - - -
-)
(- to indicate the instrument is fine to indicate settling. If two dashes (- -)
- -
-) are displayed,
Six dashes (-
- - - - - will not be displayed if the Average Tuned RF Level measurement is selected.
MEASUREMENT TECHNIQUE
The tuned R F level measurements use an IF substitution technique
RF Level. The discussion that follows focuses on calibration details. to attain high measurement accuracy over a wide range of signal levels. The basic measurement technique is discussed in Tuned
Power Calibration
An initial absolute power level calibration is made by applying a signal via a calibrated power sensor. The signal must be within both the sensor’s and Measuring Receiver’s power and frequency range. (Power should not exceed
REF.
0 to the Measuring Receiver dBm.) An initial relative power level calibration is made by applying a signal to the Measuring Receiver’s R F INPUT and selecting SET
The absolute power is first measured with the calibrated power sensor. The signal to the R F INPUT connector of the instrument where the level is measured by the IF detector. (If using a sensor module with an internal switch, such as the HP 11722A, the switching is automatic.
If using a power sensor alone, the signal source must be reconnected connector.) The signal level must be held steady during calibration. to is the instrument’s then routed
RF INPUT
The first time the CALIBRATE key is selected, the Measuring Receiver compares the level read by the Tuned RF Level IF detector to the reference level. The ratio of the two measurements is stored as a calibration factor. (The reference level tor absolute measurements is the RF Power measurement, the reference level for relative measurements is the set by the user with the SET REF key.)
The calibration factors are used to compensate for the non-linearity of the RF input gain steps
(Special Function 1).
RF Input Ranging Calibration
As the power level of the input signal is varied, the IF amplifier gain is stepped to keep the within the linear range of the IF detector. When the IF level approaches the lower limit the change in RF input attenuation.
IF of level range, the RF input attenuation is reduced to nominally 10 dB. The IF gain then compensates for
The Calibrate function enables the Measuring Receiver to create a second calibration factor by equating the power level measured before the RF range change with the power level after the change. (The input signal level rnirst not change during this recnlibration.) This new calibration
3-101
3-102
Level dBm)
-40
-50
-60
-70
-80
-90
-100
-110
+30
+20
+10
-10
0
-20
-30
-120
-130
Operation Model 8902A factor is multiplied by the calibration factor made previously (with the reference) subsequent measurements for that RF range and frequency. to be used in all
A third recalibration is required if the input signal level approaches the lower limit in the second IF range. This time, of the IF detector calibration factor is created for that RF range and frequency. The three calibration factors remain in effect
RF input gain (24 dB) as long as the frequency of the input signal is is added and within f5%
IF gain is reduced and a third of the initial frequency.
Calibration Limitations
The approximate limits of the three RF ranges for both the shown in the following graphs. The ranging points used in Automatic Operation are also indicated.
(The range can be held manually. Refer to Rang(> on
IF synchronous and average detectors are
page 3-243.) The range limits listed for the
Power Reference Range apply only for power sensors with the same sensitivity as the
Sensor Module. Other sensors might shift the Power Reference Range up or down (but 0 overall maximum level).
HP 11722A dBm is the
Power
Reference
Range
(11722A)
Range
1
Synchronous
Tuned RF Level Ranges
I
-27
AUTO
(-82)
-102
Range
2
'Swcial Function 1.9 raises Range 3 by 10 dB.
Range
3'
-61
-127
-70
-80
-90
.loo
.110
-120
-130
-40
-50
-60
0
-10
-20
-30 nput
Level dBrn)
+30
+20
+10
Power
Reference
(
Range
1 1722A)
-20
I
+30
Range
1
+30
AUTO
1-19)
-39
Special Function 1.9 raises Range 3 by 1OdB.
Range
2
-4
-7 9
Aange
3'
-38
-113
The absolute power refererence for many power sensors may overlap ranges other than the top range, it is possible to make the initial calibration against the power sensor on Range in the overlap region of two ranges) instead of Range 1.
2 or 3 (or
IF Detectors and Filters After the IF signal has been detected, the dc output from the detector is filtered and read by the internal voltmeter. Filtering combines a 10 Hz, low-pass filter in hardware
Model 8902A Operation with digital averaging of successive voltmeter readings in software. Measurements can be averaged for 0.1, 1, and 10s. The equivalent noise bandwidths are low-pass filter is always in.
10, 1, and 0.1 Hz respectively. The 10 Hz
A narrow 455 kHz IF bandpass filter (30 kHz passband) improves sensitivity to enable the instrument to measure low-level signals (where the signal-to-noise ratio is very poor). This filter primarily determines the frequency response for the 455 kHz IF and is bypassed when not needed.
Measurement sensitivity is further improved by the IF synchronous detector which locks onto and tracks the IF signal. Tracking is maintained over a 10 kHz range. Phase locking, coupled with the synchronous detection technique, reduces the measurement bandwidth to 150 Hz-giving a corresponding increase in sensitivity.
The phase lock loop locks a 455 kHz voltage-controlled oscillator diagram) the IF to the IF signal. The locked signal drifts, the VCO
VCO drifts with it to maintain synchronism.
(VCO, then becomes the synchronized drive to the detector. As
The instrument’s controller monitors the detector output
If no signal is bandwidth. During this search, six dashes (- been found. The sweep can take up to 20s.
- - - -
-) to determine if lock has been acquired. are displayed. If four dashes (-
- -
-)
IF are displayed after the search, the signal has been found. If two dashes (- -) are displayed, no signal has
Tuned the used
IF to
RF Level measurements made with the synchronous detector except that the measure the IF level. (Refer
IF
AM average detector are similar detector, operating with its
to those made with
ALC loop open, is for the block diagram.) The bandwidth is much wider and enables measurement of less pure signals.
IF average detector does not phase lock to the signal as the IF synchronous detector does, so the measurement
The wide 455 kHz bandpass filter (200 kHz passband) primarily determines the frequency response for the 455 kHz IF.
SENSOR MODULE
INPUT
SWITCH
RF POWER POWER
WIDE 455 kU?
EPOR2.5MUz
IF AMP
,:E::;,
NARROW
AN0 IF AVG
OETECTOR
/
COUNTER I DISPLAY
Tiincd RF Lrvd Simpli/icd Block Diugram
3- 103
Operation Model 8902A
Calibration Factors
An individual calibration factor is computed for each RF range-to-range change by comparing the level measured during the initial power sensor calibration to the level measured for each R F range.
This individual level measurements are ratioed to determine the relative, range-to-range calibration factors actually used in tuned RF level measurements. Display the individual calibration factors with
Special Function 38. Display the ratioed calibration factors with the % CAL FACTOR key.
The following table describes the equations used to calculate the ratioed calibration factors using individual calibration factors.
In this table, the Power Reference Range is the range used for initial calibration to the power sensor, and CF, , CF,, and CF, are the “individual” calibration factor values for the range reference to to 2, or 3 (respectively)
1,
Power
Reference
Range
1
2
3
1
CFl
CF2
CFl
CF2
CFl
Current Range
2
CF,CF2
CF2
CF3
CF2
3
CF,CF,CF3
CF2CF3
CF3
Only four calibration factors are retained in the instrument’s non-volatile memory. Separate calibration factors are maintained for the Power Reference Range of both the IF synchronous and
IF average detectors; the calibration factors for subsequent ranges are shared by both detectors.
If no actual calibration factors are available, an approximate calibration factor (accurate within a few dB) is derived.
COMMENTS
If the Tuned RF Level Calibration Is Not Possible.
If the Measuring Receiver is not making the measurement, it is probably because calibration is not possible. Following the guidelines below may enable the Measuring Receiver to complete a Tuned
R F Level measurement:
0
0
0
0
0
Change the level of the input signal until only the RECAL annunciator is displayed.
Calibrate the power sensor. (Refer to R F
Po~vcr
on
Change the IF Gain to automatic selection (9.0 SPCL).
Change the RF Input Attenuation and Gain to automatic selection (1.0 or 1.9 SPCL).
Ensure that the input-signal level does not change when the CALIBRATE key is pressed.
3- 104
Model 8902A Operation
Recovering from Mistakes in Entering Calibration Factor Values.
If an e m r is made in entering any calibration factor value with Special h c t i o n 39, selecting CLEAR allows the user to immediately re-entering the Special F'unction Code.
Calibration
Not Used.
Factors Valid for a Frequency Change of f5% or f5 When Track-Mode Tuning Is
The calibration factors obtained during calibration as the
MHz
signal limit frequency remains within has been exceeded. f5% are valid and are
used
by the instrument
change
of as long
MHz,
f5 necessitates retuning, but the previous calibration factors will be retained unless the the &5% or f5
Finer Resolution for dB Measurements
'
Special h c t i o n 32.1 enables a resolution of function also enables a resolution of 0.1 Hz
0.001 dB.
100 to 250 kHz displayed resolution of 1 Hz.) The selection of Special b c t i o n 32.0 or 32.1 is maintained through instrument power down.
32.0 Power is displayed with the normal measurement resolution of 0.01 dB.
32.1 Power is displayed with a measurement resolution of 0.001 dB.
32.2 Displays 0 if the normal measurement resolution is enabled (32.0 SPCL) and displays 1 if a h e r resolution is enabled (32.1)
Special Function 32.9; Tuned RF Level Measurements Using Track-Mode Tuning. function when making level measurements on low-level signals (greater than 40
8902A) that tend to
drift.
The track mode tuning and 32.9 can be enabled simultaneously.) is available only with the IF
Use this special average detector (Special h c t i o n s 4.4 through 4.7) which can measure levels to -110 a m . (Note that Special Fbnctions 32.1
To select track-mode tuning for a RF Level measurement: a. Instrument Preset the HP 8902A (blue key, green key). b.
C.
If using a down converter to measure microwave external L.O. frequency. Make sure signals, that the L.O. frequency results in an
HP 8902A of greater than 40 MHz when mixed with the key in
RF'
27.3 signal.
SPCL. Key in the
IF frequency to the
Set the RF signal to a level greater than -10 a m .
Allow the HP 8902A to tune to the signal. (Wait for a frequency display.) d. e. f. g. h. i.
Select 32.9 SPCL. (This is the same as entering
Mode and 27.3 SPCL.) The light in the TRACK MODE
8.1 SPCL, Log units, 'hack on at this point.
Press the MHz key to enter the manual tune mode.
Select Tuned RF Level (yellow shift key, RF Power key).
If using an HP 11722A or HP 11792A sensor module, press the CALIBRATE key to make
ZERO key. by pressing the blue key and the
Step the signal level down in amplitude and press the CALIBRATE key whenever the
RECAL annunciator is displayed.
This special function
42.0 SPCL.) sales ofice. is not available with firmware
ROM date codes 234.1985 and below. (to display the set that contains this special function, contact the nearest
Instrument serial-number prefix 2305A to 2530A do not contain this feature. For
HP sales h w a r e office. date code, select retrofit information, contact the nearest HP rev.01 MAR88 3-105
Operation Model 8902A
Comments About Special Function 32.9.
If the signal
RF appears to be lost, set the signal level of the device-under-test to greater
CLEAR (HP-IB code: BC). This key sequence forces a retune of the
Level measurements and should recapture the
Once the signal has been recaptured, step the signal signal if it has not
drifted
than
-90 dBm.
VCO during more than down for low-level measurements.
5 MHz.
If the signal frequency into the HP 8902A drifts past one of the following frequency boundaries, the
Measuring Receiver will lose the signal and the measurement process must be restarted.
Fkequency Boundaries:
40MHz, 80
MHz,
lGOMHz, 320 MHz, and 640 MHz.
Special Function 31. Tuned RF Level Noise Correction. with the IF
Use
'Ihed RF Level measurements on low-level signals. The selection of Special h c t i o n 31 is maintained through instrument power down (the Measuring Receiver being turned off and then on).
The k e d low-level measurements. (the module to
RF h c t i o n 31.1
Level measurement calibrated three is
Operating Informution PuU-Out Card stepping down in level and pressing the
RF
Then the Hp 8902A measures the noise between the
RF
RF input attneuation ranges illustrates these.) When Special key whenever the displayed.) However, when the Measuring Receiver calibrates the third
RECAL range, it switch out the signal from the device-under-test momentarily (placing input and the from the total signal-plus-noise to display the measured signal level.
IF to
Level measurement procedure is achieve accurate followed causes
50St
(that annunciator is, is the sensor at the output).
Syncronous Detector circuity.
In subsequent measurements (in this third range), the Measuring Receiver subtracts the measured noise
31.0 k
31.1 k
31.2 Display 0 if noise correction is off and display 1 if it is on.
Comments About Special Function 31.
NOTE
Special Elcnction 31.1 (for noise correction) should be entered once before making level measurements. To clear Special finction 31.1 you
31.0.
MUST
Special h c t i o n 31 can be especially useful when making measurements on down-converted signals.
Special h c t i o n s 31.0 and 31.1 can be toggled once the k e d RF1 Level calibration and without the noise. has been done with 31.1 enabled. That is, the signal can be measured alternately with the noise added to the signal
The Measuring Receiver uses a default noise value (that might be invalid) in its mesurement response if Special h c t i o n 31.1 is enabled after (instead of before) completing the RF' Level calibration sequence. (The default noise value is the last value that was measured. This value is saved through
Instrument Preset and power down.) h e d
This
42.0 special function is not available with firmware order a ROM set date codes 234.1985 and below. (To display that contains this special function, contact the nearest HP the firmware sales office. date code, select
3-106 rev. 01 MAR88
Model 8902A Operation
Do
not
use 31.1
SPCL
when d i n g any uncalibrated, or relative signal level measurement in % z e d
Sensor Module must be used
RF
Level mode without a power sensor. The
when
nuaking nned
RF
Level range-to-range
If You Prefer Manually-Entered RF Power Calibration Factors.
Not to during the RF
RF Level calibration factors. RF power calibration factors to are
used
a 1 mW reference calibration.
Selecting AUTOMATIC OPERATION or INSTRUMENT PRESET c a w the Measuring Receiver to use
Power measurement and during the first h e d
Automatic Cal Factors.
Any Manual Cal Factor will not be
used
during
RF
RF
Level absolute calibration
Level Calibration. (Refer to to
RP
4.0 SPCL, 4.4 SPCL, and SET REF Affect the First Calibration.
0
0
0
For detectors be Merent depending on the detector the
SPCL.
you will need to make a first calibration for both 4.0 SPCL and 4.4 SPCL at the tuned frequency. you the
Absolute Measurements.
test described in previous paragraphs.) This means signal is
For Relative Measurements.
use SET will
REF, you do not be bypassed for SET compares the level measured
REF key. for each detector. use by
Different detectors are
used
W F when CALIBRATE is selected the first time. either detector to used require measurement with the average detector,
Relative Measurements are by 4.0 SPCL and that the first calibration factor to the level that you set to be
4.14 made with the SET
0
REF
(These will
So if key. When a sensor module, the power sensor that the first calibration h t calibration factor when you select will be different
For Both Absolute and Relative Measurements.
Because of these four variables (absolute measurement with either detector and relative measurement with either detector), the first calibration factor can be four different values. However, the second and third calibration factor will be the same for each of these four. cases.
Special Function 4 Also Controls Selecton of Measurement Display Averaging.
Measurement averaging time during the W e d requirements of
RF its is automatically selected the measurement time using Special h c t i o n 4 is by the Measuring Receiver during the automatically selected by
Tuned RF the Measuring Receiver
Level measurement. The Measuring Receiver chooses these times based on the internal circuitry. However, experienced operators may want to increase or decrease
High Residual FM Can Affect Accuracy.
‘Ihned
RF Level measurement accuracy can be affected by residual FM on the input signal. If the residual FM is too high (refer
for Measuring Receiver specifications), the Average h e d
RF Level Measurement mode can be used
Approximate Measurement When UNCAL is Displayed.
Approximate calibration factors enable the ’Ihned RF Level measurement until the Calibrate function is used. The UNCAL annunciator indicates that approximate calibration factors are being used.
Attenuator/Gain Automatic Ranging.
The instrument automatically ranges as shown in the “Measurement Technique”. Refer to Range
for ways to avoid automatic ranging.
HOB
rev. 01 MAR88 3-107
Operation Model 8902A
High Residual FM Can Affect Accuracy.
T h e d RF Level measurement accuracy can be affected by residual FM on the input signal. If the
RF is too
Level Measurement mode can be used for Measuring Receiver specifications), the Average
%ed
Approximate Measurement When UNCAL is Displayed.
Approximate calibration factors enable the h e d is
RF Level measurement until the used. The UNCAL annunciator indicates that approximate calibration factors
Calibrate function are being used.
Attenuator/Gain Automatic Ranging.
The instrument automatically ranges
for ways as shown in the “Measurement Technique”. Refer to avoid automatic ranging. to Range Hold
3-108 rev.25JUL.87
Model 8902A Operation
IF
Level
FUNCTIONS
IF LEVEL
DESCRIPTION
The signal level in the Measuring Receiver’s optimum level. An IF level display of 100°/o
IF can be measured and displayed as modulation measurements. AM accuracy is directly affected by the is affected only if the IF level is very low. a percent of the indicates sufficient signal strength to guarantee accurate
IF level. FM and @M accuracy
PROCEDURE
To display the IF level as a percent of optimum, select IF LEVEL (Shift, i9M).
HP-IB PROGRAM CODE
IF LEVEL = S3
MEASUREMENT TECHNIQUE
Once the instrument is tuned and the IF Level function is selected, the automatic level control (ALC) loop of the AM Demodulator detects the average level of the IF. If the ALC loop is closed and there is sufficient IF signal available, the ALC loop automatically adjusts the IF gain within the loop to force the detected IF to equal the ALC reference. When the instrument is running in automatic operation, the input attenuation is adjusted to keep the IF level within range of the ALC loop.
In the ratio
Level measurement mode, the detected the two levels is expressed
IF level, the display will read 100%). If the ALC loop is open (Special Function insufficient greater than
IF level, the display
100%. If the IF level as will is a ratio in not read
(Yo.
IF level is compared to the ALC reference and the
If the ALC loop is closed and if there is sufficient
1000/0. If the IF level is too high the display will read too low, the display will read less than 1000/0.
6.2) or if there is
3-109
I
Operation
BLOCK DIAGRAM
Model 8902A
7
TO AUDIO DETECTORS
8888888888]
IF Block Diagranr
COMMENTS
Acceptable IF Level Display.
An IF level display between 99.9% and 100.1% is considered acceptable for all measurements.
Input/Output Status.
When IF LEVEL is selected, the output at MODULATION OUTPUT/AUDIO INPUT continues to outpiit the demodulated signal corresponding to the last modulation measurement selected as indicated by the MODULATION OUTPUT annunciator. If the IF level is not IOOYo, the calibration of the output is directly affected for AM and degraded for FM and QM if the IF level is very low.
Relative Measurements.
If
IF level is to be displayed relative to a reference level, enter the ratio reference using the RATIO key. (Refer to Rario
IF Levels Less Than 100%.
Error 03 (input circuits underdriven) is generated whenever the IF level is less than 1009'0 unless the
ALC loop is open, Override this Error Message using Special Function 8. (Refer to Error lI.lcwagc>
Disahlc Control
3-1 10
Model 8902A Operation
AM Depth When IF Level is Insufficient.
When operating with the AM ALC is proportional to the actual AM loop open or when the IF level is insufficient, the displayed AM depth, and the displayed IF level is proportional to the average carrier level. The actual AM depth can computed as the ratio of the two readings with the following formula:
A M i n % = demodulated ac average carrier level loo%= displayed displayed
AM
I F level x 100%
The Ratio feature can be used the AM to key and enter the IF level simplify this calculat.ion: First, measure the on the numeric keys. Then press the displayed although the IF level is not optimum.
IF
RATIO level, then press key. AM is now
Guidelines
for
Measurements when AM ALC is Off.
In most circumstances, when for FM the AM ALC is off (loop open), use 1F levels greater than measurements and less than or equal to 100% for AM measurements. or equal to
3-1 11
Model 8902A Operation
Peak Tuned RF Level
FUNCTIONS
Special Function 36 (Peak Tuned RF Level)
DESCRIPTION
Another method the Measuring Receiver can use to measure level is Special Function 36. The average power measured in this case is actually the peak level of the down-converted RF input falling in the
IF. The term “peak level” refers to the fact that a peak-responding IF detector is used to measure the signal level. The internal controller converts this level to average power and displays the result.
(See the block diagram in “MEASUREMENT TECHNIQUE”.) The Peak Tuned RF Level function is not calibrated, and so it is not as accurate or sensitive as the Tuned RF Level function (initiated with the TUNED RF LEVEL key) that must be specifically calibrated for each frequency. The Peak
Tuned RF Level function enables the instrument to measure the level
35) measurement modes. of frequencies that are drifting, or to determine flatness as a function of carrier frequency. This function is more sensitive than the
RF Power or RF Level (Special Function
PROCEDURE
To make a peak tuned RF level measurement, first tune the instrument to the input signal by selecting
AUTOMATIC OPERATION. Key in 36.0 SPCL.
HP-IB PROGRAM CODES
LOG
= results
LN
= LG
SPCL = SP
VOLTS units = VL mV units = MV uV units = UV
WATTS units = WT
MEASUREMENT TECHNIQUE
When the Measuring Receiver is tuned, all the power falling within the IF bandpass filter is amplified and peak detected. The detected power is then measured by the voltmeter and displayed in the selected fneasurement units.
3-1 13
Operation Model 8902A
LOCAL
Peak Titned
RF
Level Measirrc.ment Block Diagram
COMMENTS
Input/Output Status.
When the peak tuned RF level measurement is selected, MODULATION OUTPUT/AUDIO INPUT is blanked. AM OUTPUT and FM OUTPUT (rear panel) remain active during this measurement.
Relative Measurements.
If the peak tuned RF level is to be displayed relative to a reference, enter the value as a ratio reference using the RATIO key. (Refer to Ralio
Accurate Power Measurements.
Use an external power sensor to make accurate, absolute power measurements. (Refer to RF Power
or to Tirncd RF Levcl
3-1 14
Model 8902A Operation
Attenuator Measure men ts
FUNCTIONS
SET REF, Special Function 26 (Set Reference)
DESCRIPTION
By setting a zero-reference at the current measurement level, the gain of linear devices (such as attenuators and amplifiers) can be measured directly and accurately. The current RF level then becomes the reference for all subsequent tuned R F level measurements made at that frequency.
Special Function 26 enables the Measuring Receiver reference) the Attenuator Measurement mode. to exit or to re-enter (using the previous
The SET REF key should be used instead the restrictions.) of the RATIO key for relative power measurements. (The
Ratio function is still available but with restrictions. Refer to “COMMENTS” for an elaboration of
PROCEDURE
To make relative power measurements in the Attenuator Measurement mode, connect an R F signal through an RF cable (or sensor module) to the R F INPUT connector
Tune the R F source to the frequency of interest by selecting FREQ. of the Measuring Receiver.
Select TUNED RF LEVEL (Shift, RF POWER) and wait for the measurement result to be displayed.
Select SET REF (Blue Key, ZERO) to set the initial reference for subsequent relative measurements.
Select LOG/LIN to change the display to read in Yo or dB units. As the input level changes, the level relative to the initial reference is displayed.
As the input signal level approaches a maximuni or minimum limit, the RF input circuits must re-range to accomodate the new level. If the input circuits are re-ranging for the first time at the signal frequency, the instrument must recalibrate. If RECAL is displayed, press the CALIBRATE key and hold the signal level steady until a valid measurement is displayed. If UNCAL is displayed, set the input signal to a level at which RECAL is displayed and press the CALIBRATE key. (Two input range-to-range calibration factors are stored for each of the two IF detectors. Refer to Tuned
R F Level Calibration and Calibration Factors for a description of calibration factors and their derivation.)
Key in 26.0 SPCL or TUNED absolute Tuned RF Level mode. (Refer to Special Functions for a more specific selection procedure.)
Key in 26.1 SPCL to re-enter the Attenuator Measurement mode using the previous reference.
HP-IB PROGRAM CODES
CALIBRATE on =
LIN results = LN
LOG
SPCL =
=
SP
= LG
RF
CI
TUNED RF LEVEL = S4
3-1 15
Operation Model 8902A
INDICATIONS
Selecting TUNED RF LEVEL might elicit all of the following responses:
Two dashes (--) indicate that the instrument is searching for the input. signal but has ,not found it.
This is the normal automatic tune mode.
Four dashes (----) indicate that the signal has been found and the instrument measurement. is awaiting a settled
Six dashes (------ ) indicate that the instrument is to locate the signal in its narrow IF filter. (This indication is used only with the detector.) fine tuning the IF synchronous detector’s VCO
IF synchronous
----
, then the measurement result.
----, ------,
If the signal level approaches a maximum or minimum limit of the RF input circuits and if the next input range has not been previously calibrated at that signal frequency, the RECAL annunciator lights to indicate the need for range calibration. Hold the signal level steady and select CALIBRATE.
If the signal level goes beyond a maximum or minimum limit of the RF input circuits, and it cannot be calibrated at that level, the UNCAL annunciator lights. Re-adjust the signal level until the UNCAL annunciator goes
CALIBRATE. off and the RECAL annunciator lights, then hold the signal level steady and select
If both the UNCAL and RECAL annunciators are lighted, the instrument can still be calibrated, but the displayed reading is not yet calibrated.
The LED within the SET REF key (the ZERO key) will not light when pressed.
MEASUREMENT TECHNIQUE
The SET REF key sets the Measuring Receiver to make tuned R F level measurements relative to an initially-set reference. Measurement restrictions that apply are the same as for the normal Tuned
R F Level measurement mode.
The major difference between absolute and relative tuned RF level measurements is the way the initial reference is obtained. For absolute measurements, the initial level measurement made with the IF detector is equated the RF to a measurement made on the same signal with a power sensor (essentially
Power measurement). For relative measurements, the initial level measurement made with the IF detector is equated to IOO(Yo.
Since the relative measurement uses the same measurement, the absolute and relative measurements share the calibration factors for the two internal R F input range changes. Thus relative level measurements can be made on signal levels ranging from 0 to -127 dBm. Also,
IF detectors and RF input ranges as the absolute when measurement modes are switched between relative and absolute, the only recalibration necessary is for the initial reference.
(Refer to Tirntd R F Levd
level measurement technique.
for a more detailed description of all aspects of tuned R F
3-1 16
Model 8902A Operation
COMMENTS
Input/Output Status
Accurate level measurements can be made only on cw signals. The MODULATION OUTPUT/AUDIO
INPUT is blanked during tuned RF level measurements.
Measurement Limits
Relative measurements cannot be made on dBm.
RF signals with absolute levels outside the range 0 to -127
Valid Measurements Can Only Be Made on Tuned Signals
The Measuring Receiver must be tuned to the input frequency before valid tuned can be made. The instrument can be manually tuned to the frequency of interest either before or after the TUNED RF LEVEL Key is pressed. (Refer to RF Requency Thing
FW
level measurements
If the tuned frequency moves more than f5 from the frequency at which the power sensor reference was taken, the instrument must be retuned.
Using Ratio with Tuned RF Level Measurements
For most measurement modes, when the Ratio feature is used, a known reference is first established either by keying in the desired reference or by using the displayed measurement as the reference. hrthermore, the established reference can always be recalled (using PREVIOUS RATIO or Special
Function 11.2). In the Attenuator Measurement mode the initial SET REF reference cannot be recalled.
Also, when using the Ratio feature with T b e d ignored.
RF Level, the input RF range recalibration data is
CAUTION
Do not use 31.1
SPCL
when making any uncalibrated, or relative signal level measurement in lbned RF Level mode without a power sensor.
The
Sensor Module must be used when making n n e d RF Level range-to-range calibrations with the AVG Detector. rev.25JUL87 3-117
Model 8902A Operation
Selective Power Measurements (Option 030)
FUNCTIONS
Special Functions 23 (External LO) and 24 (Selective Power Measurements)
DESCRIPTION
The Series 030, Selective Power Measurement Options enable the Measuring Receiver to measure adjacent-channel power and single-sideband noisc on continuous wave of
RF signa1s.l Both measurements basically consist of tuning the instrument to the RF signal, measuring the IF level in the passband of re-measuring the in the passband desired measurement result (expressed in dB).
(CW) a selected IF filter, then offselting the signal onto the skirt of the IF filter and
IF level. Otfsetting the signal places a portion of the sideband noise of the carrier the IF filter. The ratio of the out-of-band IF level to the in-band IF level is the
The measurement procedure requires that the operator step through and increment either the local oscillator a sequence of special functions
(LO) or the signal source. For RF signal frequencies above
300 MHz, an external LO is recommerided for greatest sensitivity and accuracy. Special Function 23 switches the LO between internal and external. The external
(Since Option Series 030 provide rear-panel available in conjunction with the 030 Series Options.)
LO connects to a rear-panel connector.
LO input and output connectors, Option 003 is not
The 030 Series Options include the choice of two IF bandpass filters installed. The bandwidths of these IF filters match the requirements of specific industry standards for measuring adjacent-channel power. The following table lists the optional filters and their bandwidths.
I
Filters
12.5 kHz
25 k H t
30 kHz
Adjacent Channel Filter
Adjacent Channel Filter
(Cellular Radio) Filter
Carrier Noise Filter
I
Options
Option 032
Option 033
Option 035
Option 037
I rcv. 1 SMA Y86 3-1 19
Operation Model 8902A
PROCEDURE
The following procedures are examples of typical measurement applications. These procedures describe the steps for measuring adjacent-channel power and single-sideband noise.
ADJACENT CHANNEL POWER MEASUREMENTS
Two procedures are available. The first procedure measures the lower adjacent channel power. The second procedure measures the upper adjacent channel power.
To
Measure
the Lower Adjacent Channel Power
Setting Up the
LO
1. T h e to the input frequency. (Selecting the FREQ key automatically tunes the Measuring
Receiver to the input frequency. Keying in the input frequency value (in MHz) followed by the
MHz key manually tunes the Measuring Receiver to the frequency value keyed in. For more information about tuning, refer to
RF
Requency
nning
2. Press the MHz key to manually tune and center the IF.
3. Select 24.0 SPCL to enter the Selective Power Measurement mode.
4. Select whether an external LO or the Measuring Receiver’s internal LO will be used. If the internal LO will be used, go to the LO INPUT connector on the rear panel of the Measuring Receiver. (More information about the LO to step 7.
INPUT is available in
If an external LO will be used, connect the LO signal source
LO Input and
LO
Output
5. Set the external LO source frequency amplitude to 0 a m . to 455 kHz greater than the input frequency, and its
6. Key in 23.1 SPCL to set the LO to external.
Setting the Reference
7. Select 24.1 SPCL to establish the IF reference value (in volts).
8. Select 24.2 SPCL to set the reference to 0 dB.
9. Adjust the LO frequency until the maximum value is displayed. The Measuring Receiver’s automatic tuning capability measures an IF value close to the peak, but the internal circuitry does not specifically check for a peak. This step enables you to fine tune to the peak of the signal. a. If using an external LO, step the LO frequency in small increments until the peak value is measured. b. If using the internal LO, set the desired increment value (in kHz) and step the LO using the .h kHz 4 kHz keys until the maximum value is displayed. (It is possible input signal instead of the to tune the
LO. Refer to Comments,
“Frequency Offsetting” on page 3-127.)
10. Reselect 24.1 SPCL to establish the IF reference value (since that value has now been peaked).
11. Reselect 24.2 SPCL to set the reference to 0 dB.
Measuring the Lower Adjacent Channel Power
12. Decrease the LO frequency value until -6 dB is displayed. Note the frequency difference between the source and the LO. This frequency difference is relative to the 6 filter. (Once the 6 dB corner of the IF bandpass corner frequency has been determined, the corner need not be remeasured when new measurements are made with that filter.)
3-120 rev.22DEC88
Model 8902A Operation
13. Decrease the LO frequency by an offset of either 8.25 kHz, adjacent channel being measured (refer to the table below).
13 W z , 17 kHz depending on the
Channel Spacing in kHt
12.5 kHz
20 kHz
25 kHz
6 dB
Displacement of the
Point per CEPT (in kHz)
8.25
13 kHz kHz
17 kHZ
14. The value displayed is the adjacent channel power measurement result.
To
Measure
the Upper
Adjacent Channel Power
Setting Up the
LO
1. Tune to the input frequency. (Selecting the FREQ key automatically tunes the Measuring
Receiver to the input frequency. Keying in the input frequency value (in
R F Requency Thing
MHz)
followed by the
MHz key manually tunes the Measuring Receiver to the frequency value keyed in. For more information about tuning, refer to
2. Press the
MHz
key to manually tune and center the IF.
3.
4.
5.
Select 24.0 SPCL to enter the Selective Power Measurement mode.
Select whether an external internal LO will be used, go
LO to or the Measuring Receiver’s internal LO will be used. If the step 7. If an external LO will be used, connect the LO signal source to the LO INPUT connector on the rear panel of the Measuring Receiver. (More information about the LO INPUT is available in W Input and W Output
Set the external LO amplitude to 0 dBm. source frequency to 455 kHz less than than the input frequency, and it’s
6. a. If using the internal LO, on the Measuring Receiver select 910 4) kHz. This tunes the
Measuring Receiver to the image frequency of the LO. display will not match the input frequency value.
At this time, the RF frequency
Key in 23.1 SPCL to set the LO to external.
Setting the Reference
7. Select 24.1 SPCL to establish the IF reference value (in volts).
8. Select 24.2 SPCL to set the reference to 0 dB.
9. Adjust the LO frequency until the maximum value is displayed. The Measuring Receiver’s automatic tuning capability measures an IF value close to the peak, but the internal circuitry does not specifically check for a peak. This step enables you to fine tune to the peak of the signal. a. If using an external LO, step the measured.
LO frequency in small increments until the peak value is b. If using the internal LO, set the desired increment value (in kHz) and step the LO using the fi kHz and 4 input signal instead of the LO. Refer to
(It is possible to tune the
“Frequency Offsetting” on page 3-127.)
10.
11.
Reselect 24.1 SPCL to establish the IF reference value (since that value has now been peaked).
Reselect 24.2 SPCL to set the reference to 0 dB. reu.22DEC88 3-121
Operation
Measuring the Upper Adjacent Channel Power
12.
Model 8902A
13.
Channel Spacing in kHz
12.5 kHz
20 kHt
25 kHz
6 dB
Displacement of the
Point per CEPT (in
8.25 kHz
13 kHz
17 kHz kHz)
14.
SINGLE-SIDEBAND NOISE MEASUREMENTS
Use this procedure only when Option 037 has been installed.
Setting Up the LO
1. ’hne to the input frequency. (Selecting the
Receiver to information about tuning, refer to RF
FREQ key automatically tunes the Measuring
MHz key manually tunes the Measuring Receiver to the frequency value keyed in.
Requency Timing
For the more
2. Press the MHz key to manually tune and center the IF.
3. Select 24.0 SPCL to enter the Selective Power Measurement mode.
4. Select whether an external LO or the Measuring Receiver’s internal internal to the
LO
LO about the will be used, go to step 7. If an external
LO will be used. If the
LO will be used, connect the LO signal source
INPUT connector on the rear panel of the Measuring Receiver. (More information
LO INPUT is available in LO Input and LO Output
5. Set the external amplitude
LO to 0 dBm. source frequency to 455 kHz greater than the input frequency, and it’s
6. Key in 23.1
SPCL
to set the LO to external.
Setting the Reference
7. Select 24.5 SPCL to establish the IF reference value (in volts).
8. Select 24.6 SPCL to set the reference to 0 dB.
9. Adjust the LO frequency until the maximum value is displayed. The Measuring Receiver’s automatic tuning capability measures an IF value close to the peak, but the internal circuitry does not specifically check for a peak. This step enables you to fine tune to the peak of the signal. a. If using an external LO, step the LO frequency in small increments until the peak value is measured. b. If using the internal LO, set the desired increment value (in kHz) and step the LO using the kHz and JJ kHz keys until the maximum value is displayed. (It is possible to tune the input signal instead of the LO. Refer to
“Frequency Offsetting” on page 3-127.)
10. Reselect 24.5 SPCL to establish the IF reference value (since that value has now been peaked).
11. Reselect 24.6 SPCL to set the reference to 0 dl3.
3-122 rev.22DE C88
Operation Model 8902A
Making the Single-Sideband Noise Measurement
11. If you want the measurement to be displayed as total power in the the next step. If you want the measurement to be normalized to 1 kHz select 24.7 SPCL. to
12. Adjust the LO frequency by the desired offset to display the noise value. The value displayed is the single-sideband noise measurement result.
I
24.3
24.1
24.2
24.4
24.5
24.6
24.7
24.8
24.9
Additional Special Functions for Single-Sideband Noise
These special fiinctions enable you to change and display the noise measurement bandwidth. The noise measurement bandwidth is measured and entered at the factory and probably does not need to be remeasured unless operating conditions for the Measuring Receiver change radically.
1. Special Function 24.8 Changes the noise measurement bandwidth used in single-sideband noise measurements. The value entered (in units and 0.02 MHz). To of MHz) must be between enter a noise measurement bandwidth key in bandwidth expressed in MHz
100
24.8 and press the MHz key. This factor
SPCL kHz then key in the is stored in non-volatile memory. Determination of the noise measurement bandwidth is usually done by numerical integration of the IF filter response.
2. Special Function 24.9 Displays the value of the noise measurement bandwidth used in conjunction with Special Function 24.7. The displayed value times out after a few seconds.
~
Sets the LO to internal.
Sets the
Displays the status of the LO: (O=lnternal, l=Exter- nal).
Sets the Measuring Receiver to the Selective Power
Measurement Mode.
Selects the wide-bandwidth IF filter for adjacent- channel or cellular radio power measurements. Dis- plays the IF level (in volts).
Establishes the level measured with 24.1 SPCL as the
0 d5 reference.
Selects a narrower bandwidth IF filter than 24.1
SPCL for adjacent channel power measurements.
Displays the IF level (in volts).
Establishes the level measured with 24.3 SPCL as the
0
~ ~~ ~~ ~ Selects a very tvrrow bandwith IF filter (2.5 kHz) for the single-sideband noise measurement. Displays the
IF dB
Special
LO to external. reference. level (in volts).
Establishes the level measured with 24.5 SPCL as the
0 ai3 reference.
Displays the noise measurement as normalized to a
1 Hz bandwidth.
Sirmmary of Special Firndions 23 and 24
Function Description
Enables setting of the value of the noise measure- ment bandwidth.
Displays the value of the noise measurement bandwidth.
Comments
The display times out after a few seconds.
This special function must be selected before any selective power measurements can be made.
Used with 24.2 SPCL.
The bandwidth of the IF is determined by the Option
Series 030 Filter installed.
Used with 24.4 SPCL.
Used with 24.6 SPCL.
Can only be used with Option 037.
Can only be used with Option 037.
Can only be used with Option 037.
Can only be used with Option 037.
Can only be used with Option 037.
I
3-123
Operation
Amplitude
(a.)
No
Frequettcy
Oflsf
Amplitude
-
~ R F
IF
Amplitude
(6.) Freqrtency Ogsef by Increasing
RF
Signal Freqliency
3-124
455 kHz
(c.)
Freqirency Offset by Increasing LO Frequency
Signal Timing Illitstrating Frequency Offsetting
Model 8902A
Model 8902A Operation
MEASUREMENT
TECHNIQUE
The Series 030 Options add more I I; signal woccssi
Measurement Option simplified block diagram.) ng circuitry to the Measuring Receiver including programmable IF amplifiers and filters and a triw rms IF detector. (Refer to the Selective Power
Initializing.
The Measuring Receiver must be set up for the first part of the measurement which establishes the
IF reference level. This is most easily done by keying in Special Function 24.0 which:
0 holds the RF input attenuation; sets the IF to 455 kHz, retiines the manual-tune, low-noise mode;
LO to accommodate the 455 kHz IF, and sets the LO to the
0 inserts the RF input High-Pass Filter (which limits the lowest RF input frequency to 10 MHz but filters any low-frequency RF input signals from interfering with the measurement); and disables Error Messages 01 through 04.
The Measurement Sequence.
The first step in the measurement sequence is to tune in the IF filter passband. Refer to (a.) in the pre1:ous figure “Signal Tuning Illustrating Frequency
Offsetting”. After the instrument is properly tuned the
RMS Detector. The in-band 1F Ievcl is clellned as
;i to LO to
IF the R F input signal ratio reference. to center the
(in-band) level is measured with the
IF
IF
Next the frequency is offset either by tuning the KF input signal (if this is possible) or by tuning the
LO as illustrated in (b.) and (c.) oi’tlie same figiiic. Note that tuning is in opposite directions. If it is desired to offset the IF to the uppcr skirt o the IF Ijlter, the RF frequency must be decreased or the
LO frequency increased.
RMS of
1F
1F level measurement is made with the same level has decreased considerably, the IF gain is adjusted to bring the level within the optimum range of the IF RMS Detector. The ratio of the out-of-band IF level to
IF
IF the in-band level is computed and displayed. Out-of-band IF signal appears in the IF passband because
0 sideband noise on the RF input signal,
0 modulation sidebands on the R F input signal (if the signal is modulated),
0 sideband noise on the LO, and
0 the limited signal rejection in the stopband of the IF bandpass filter.
Since it is desired to measure only the first two contributions (that is, the contributions of only the
R F input signal), care must be taken to choose the correct frequency offset, the proper proper IF filter.
LO, and the
3-125
Operation Model 8902A
DISPLAY
IOPTION SERIES 030 ONLY1
~
~ ~~~~~
Selective Po wt>r Mt~asiiremen Sirnpl(fitd Block Diagrurn
COMMENTS
Frequency Modes Possible During the Selective Power Measurement.
During the selective power measurement, the instrument must be properly tuned to the signal and must be in one of the following RF Frequency measurement modes:
0
R F Frequency (the FREQ key, HP-IB Code: M5).
R F Frequency Error (the S, FREQ ERROR keys, HP-IB Code: S5),
0
IF Freque:icy (Special Function 34, HP-IB Code: 34,0SP), or
0
LO Frequency (Special Function 33, HP-IB Code: 33.0SP).
When To Use an External LO.
A low-noise, external
19
LO is recommended for RF inpui frequencies above 300 MHz. Also, can be selected for lower phase noise and finer resolution in its frequency steps. an external
When an external
(such for as 100 MHz)
LO is used. the internal LO should be manually tuned to an arbitrary frequency to defeat automatic signal search. Refer to tuning information. (Note that the kHz IF will
RI:Frcqiicw*y be used.)
Tuning
3- 126
Model 8902A Operation
Frequency Offsetting.
The IF frequency can be offset by one of the following three methods:
0 offsetting the RF input signal.
0
0 offsetting the external offsetting the internal
LO, or
LO using the fi kHz or kHz keys.
An increase in the RF input signal moves the IF signal down the lower skirt of the IF bandpass filter.
An increase in the skirt. Refer to
LO frequency (either external or internal) moves the
Meuwrcmenf Tcchniqire
IF signal down the upper for an illustration of this.
The measurement specification may require that the frequency offset be made from the frequency of the IF bandpass filter.
6 dB corner
Finding the IF Peak.
For maximum accuracy, the frequency offset should be relative to the frequency at which the I F sigrial is peaked in the IF bandpass filter. (IF filter ripple can be as high as 2 dB.) Automatic tuning brings the IF clo$e to the peak, but the instrument controller does not specifically check for an
IF peak, Finding the IF input signal or external peak is most easily accomplished possible) or by tuning the external
LO is tuned until the displayed by incrementing the internal LO is
LO
IF by tuning the while Special Function 24.1, 24.3,
RF input signal (if this is or 24.5 is active. The R F voltage is at its peak. Finding the IF peak similar, but the active special function must be re-entered after each frequency increment. Tuning requeires a range of only a few kHz.
In all the measurements, you can tune the input signal instead of the the source is tuneable. However, you must tune the source opposite the LO. For example, if yoti tune the LO
LO. This is the easiest way if to the direction you would tune down, you would tune the source up in tiequency.
3-127
Model 8902A Operation
IF Output
Do
OUTPUT
than 40 Vdc or greater than +I5 dBtn into the rear-panel
DESCRIPTION
The rear-panel IF OUTPUT (a female monitoring of the Measuring Receiver’s
BNC
IF connector) provides a buffered output to enable signal. The ac-coupled signal ranges from 150 kHz to
2.5 MHz and normally varies in level from -27 to -3 dBm (into 50 ohms). The level variation depends on the RF input signal level, RF input attenuation or gain setting, and the measurement selected.
The uses the wide, 2.5
455
3 dB bandwidth kHz bandpass filter. of
MHz the signal at IF OUTPUT is approximately low-pass filter; approximately bandpass filter; and approximately 30 kHz
200 kHz
3 MHz when the instrument when the instrument uses the wide, when the instrument uses the narrow, 455 kHz
At any particular input level and front-panel setting, the flatness frequency varies, is typically within f5%. of the IF OUTPUT, as input
BLOCK DIAGRAM
10 dB INPUT k$y!
IFAMP b
TO OTHER
MEASUREMENT
CIRCUITS
IF BUFFER
.
IF OU_TLUT
2
LOCAL
Il:
Oirfpirt Block Diagram
3- 129
Operation Model 8902A
COMMENTS
Use the Measuring Receiver as a Down Converter.
The Measuring Receiver can be used as a high-quality, automatically tuneable, down-converter. Use the IF OUTPUT as the down-converter’s output.
Adjacent Spurious Signals.
Check for close-in spurious signals on the RF input by connecting a spectrum analyzer to IF
OUTPUT.
When connecting instruments such as counters to the IF OUTPUT, check that they do not inject spurious signals into the IF path. Spurious signals in the Measuring Receiver’s IF may generate measurement error.
3-130
Model 8902A
Operation
External Attenuation (dB)
FUNCTIONS
dB EXT ATTEN, Special Function 25 (External Attenuation dB)
DESCRIPTION
Level measurements can be scaled to correctly indicate the power at the input of an external attenuator or amplifier connected to the instrument.
Special Function 25.2 causes display of the value of the selected external dB attenuation or gain.
PROCEDURE
To enter external attenuation:
1. Select the keys corresponding to the magnitude of external attenuation or gain expressed in dB.
2. If the offset is gain rather than attenuation, designate the value as negative by selecting the
Blue Key and minus-sign (-) key (the decimal key). attenuation.
No sign indication is necessary for entering
3. Select dB EXT ATTEN (Blue Key, LOG/LIN).
To display the current offset in dB, key in 25.2 SPCL.
To exit external attenuation, select dB EXT ATTEN again.
To re-enter external attenuation, select dB EXT ATTEN again.
EXAMPLE
To account for an external 10 dB amplifier connected to the instrument:
LOCAL
(keystrokes)
(program codes)
Data
3-131
Operation Model 8902A
HP-IB PROGRAM
CODES
dB EXT ATTEN off = NO dB EXT ATTEN on = N1
SPCL = SP
When the dB EXT ATTEN key is pressed, the Measuring Receiver displays subsequent level measurements using the entered dB offset.
COMMENTS
Input/Output Status.
External Attenuation Value is Stored Through Other Measurement Selection.
If another Measurement mode is selected while the external attenuation function is enabled and a level Measurement mode is re-entered, the instrument automatically re-enters the external attenuation mode with the previous offset.
3-132
Model 8902A Operation
Remote Control
RF
Switch
DESCRIPTION
A compatible, external power sensor is required for making accurate, absolute RF power or tuned RF level measurements. The Measuring Receiver can be used with the following sensor configurations:
.A power sensor selected from the HP 8480 series sensors.
.A sensor module (such as the HP 11722A) that contains a power sensor, an R F switch, and an R F coaxial cable. The Measuring Receiver controls the R F switch in the sensor module to automatically switch the RF input signal between the RF INPUT of the Measuring Receiver and the power sensor as measurements require.
.A sensor module, built by the user, that includes a power sensor (from the HP 8480 series sensors), an RF cable, and an RF switch (such as the HP 33311 series or the HP 8761A). The rear-panel
REMOTE CONTROL SWITCH outputs enable the Measuring Receiver the RF input signal between the RF input measurements require. to automatically switch of the Measuring Receiver and the power sensor as
NOTE
A n HP 478A is a standard scnsor hiit is not compatihlc with thc Mtasiiring
Receiver.
For
relative power mcaasiirements,
no
sensor is nrcdcd.
PROCEDURE
The following procedure provides a few guidelines for setting up and operating a remotely controlled sensor module.
Connect the RF switch, power sensor, RF cable, and Measuring Receiver as shown in the
DIAGRAM. SENSOR
BLOCK rear-panel remote control switches are to be used with a user-built sensor module. The control lines are in
Do not connect a sensor module (such as the HP 1 1722A) to the parallel, and the internal switch drive circuits cannot drive both.
The remote outputs are capable should be of of driving both 5V and 12V to 15V switch solenoids. The solenoids a latching type, but they need compatible RF switches are the HP333
15V solenoid). not have automatic drive disconnect. Examples of
1 IB, Option 01 1 (5V solenoid) or the HP 8761A (12V to
Proceed with selected measurements. This user-built module will enable the Measuring Receiver to automatically switch between its inputs as measurements require.
3-133
Operation
BLOCK DIAGRAM
Model 8902A
SENSOR MOOULE
RF
INPUT
I
/-,
I I
I
I r--
- -
I I
I I
1 - 1
I I
I
- -
VOLTMETER
I
-
,A
' r - - - - - -
L - - - - - J
1
I r - - - - - i
I
L - - - - - J
--1
~~~~
UlocA Iliagram qf Rcvnotc Control R1.' Switch
COMMENTS
REMOTE CONTROL Outputs are Exclusive to Compatible Switches.
The rear-panel REMOTE CONTROL outputs are not intended as general-purpose switch drives.
The output shoiild only be used with compatible RF switches.
3-134
Model 8902A Operation
Frequency Measurements (RF, LO, IF) Contents
RF INPUT FREQUENCY MEASUREMENTS
R F Input Frequency
0
R F Frequency Tuning
0
R F Frequency
0
How to select the different automatic and manual tune modes.
How to
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to measure the frequency
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . measure the difference between the input frequency and the frequency instrument is tuned. to which the
3-137
3-141
3-147
IF FREQUENCY
IF Frequency
0
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to measure the instrument’s IF frequency (the down-converted RF input signal).
3-151
LO FREQUENCY
LO Frequency
0
0
0
How
How
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LO Input and LO Output
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . to provide an input for an external LO. to provide an output for the internal LO.
3-153
3-155
GENERAL FREQUENCY MEASUREMENT FUNCTIONS
RF Frequency Resolution
0
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to manually set the display resolution (except audio frequency).
3- 157
3-135
Model 8902A Operation
RF Input Frequency
FUNCTIONS
FREQ
DESCRIPTION
The Measuring Receiver can measure R F input signals from 150 kHz to 1300 MHz. (Higher frequencies can be measured using an external mixer
.) as described in Frtqtrcnc'y Oi).itv Conlrol on
To count input frequencies between 2.5 and 1300 MHz, the Measuring Receiver uses heterodyning; to count input frequencies from 150 kHz to 2.5 MHz, it counts the input directly.
In most circumstances, when using manual tuning and when the approximate frequency with Tuned R F Level, the range can be extended below
-
100 dBm. is known, the instrument can count signals with power levels less than -60 dBm. When used in conjunction
PROCEDURE
To make an input frequency measurement, first tune the instrument to the input signal (select
AUTOMATIC OPERATION or refer ways to R F Frqircncy Tuning
to learn about more to tune the Measuring Receiver.) Select FREQ.
Manual tuning will be necessary when measuring low-level signals (inputs less than -25 dBm from
150 kHz to 650 MHz or less than -20 dBm from 650 to 1300 MHz).
HP-IB PROGRAM CODE
FREQ = M5
MEASUREMENT TECHNIQUE
For input frequencies between 2.5 and
(LO) to the signal and down-converts it to an intermediate frequency (IF). The IF signal is amplified, limited, and counted. The and the result is displayed.
LO
1300 MHz, the Measuring Receiver tunes its local oscillator frequency is also counted. The IF is subtracted from the LO frequency
For input frequencies below 2.5 MHz the R F input signal passes directly into the IF without down-conversion. The IF is counted and displayed.
3-137
Operation Model 8902A
DISPLAY
BBBBBBBBBDl
RF Inpirf Freqiiency Mt>asirrement Block Diagram
COMMENTS
Input/Output Status.
When the instrument is measuring input frequency, the output signal at MODULATION
OUTPUT/AUDIO INPUT represents the last modulation measurement made as indicated by the
MODULATION OUTPUT annunciator.
Relative Measurements.
If RF frequency is to be displayed relative to a reference, enter the value the RATIO key. (Refer to Ralio
as a ratio reference using
Increasing Measurement Sensitivity.
The RF Amplifier can be inserted (using Special Function sensitivity when the input signal level
is less than -25
1) to increase the Measuring Receiver’s dBm. (Refer to RF /tipu/ A~/crtitaliow
Gain
Limiting Low-Level Signal Measurements.
When the Error Message Disable Control speial function example). However, other Special Function levels. (Refer to Error is in the automatic selection mode (Special
Function 8.0)’ very low-level signals can be counted without generating error messages (Error
Mwa,w Disahk Conlrol
8 codes enable error messages at much higher signal
03 for
Centering the IF Does Not Affect Frequency Measurements.
It is valid frequency measurements. A frequency is displayed the important kHz to note that when FREQ is selected, the IF need not be exactly centered to make
(up arrow) or kHz (down arrow) functions will as long not as a signal is present in the IF. Using change the displayed input frequency
3- 138
Model 1902A
Operation even though tuning has been altered. tuning error if desired.
If desired, the frequency error function can be used to indicate
Frequency Agile Sources.
For best results, use the manual-tune mode when working with frequency agile sources, With agile frequency sources (such as frequency synthesizers), it conversion, or is possible for the carrier or its harmonics unexpectedly into the IF passband either directly (for frequencies below 2.5 MHz), by down-conversion of an image (the signal frequency minus the to hop by normal down-
LO approximately equals the IF). Depending on the frequency, amplitude, and timing of the signal source and the tuning mode of the Measuring Receiver, a tuning error may or may not be sensed. If the instrument does not retune, frequency and level measurement results may not be as expected.
When Measuring Frequency Agile Sources or Multiple Signal Sources.
Whenever tuning to signals less than 2.5 MHz, the input signal passes directly into the IF. The LO is used only to turn on the mixer. However, since the Measuring Receiver arbitrarily sets the LO to
101.5 MHz, a enable you to make some desired measurements. Note that when using this method you should disable Error passband is created from 99 to problem, manually tune the LO so region of the input spectrum. This method
01 (by selecting 8.1 SPCL) is
104 MHz. If this frequency band causes a measurement the passband for the down converted signal falls in an unoccupied not a preferred way to make measurements, but it might to prevent the Measuring Receiver from trying to tune to a down-converted signal rather than the signal that is less than 2.5 MHz.
Manual Tuning.
When tuning manually, it is possible in the image passband; for example, when using the
Frequency measurements are inaccurate when the instrument
Freqiiency Tuning
to accidentally adjust the kHz (up arrow) and kHz (down arrow) keys. is
LO so that the input signal falls tuned to an image. (Refer to for an illustration of the image passbands.)
RF
Measuring Frequencies below
-
60 dBm.
The high gain of the signals below -60
IF Amplifier and Limiters makes it possible to measure the frequency of input dBm. In automatic tuning. the instrument tunes to the strongest signal at the input.
When manually tuned to the approximate input frequency, the instrument ignores more powerful signals when they or their images fall outside the IF passband.
Extend the range of measurable signal levels amplifier (Special Function 1). (Refer to
RF
for automatic and manual tuning by inserting the
Iripir( Aflcntralion and
Gain
RF
Input/Output Status.
When the FREQ MODULATION OUTPUT modulation signal, filtered, and/or de-emphasized (except indicated by the MODULATION OUTPUT signal continues
PRE DISPLAY) as previously selected (as annunciator). Calibration of t.o be the last selected this output depends on
1F signal level and should be assumed only when all errors are enabled (Special Function 8.8). the
3-139
Model 8902A Operation
RF Frequency Tuning
FUNCTIONS
TRACK MODE, AUTO TUNING, DISPLAY FREQ INCR, kHz $ and kHz
DESCR
I
PTlON
The Measuring Receiver is considered tuned to an input signal when the frequency of the Local
Oscillator (LO) tuned either 1.5 MHz or 455 kHz above the input signal, depending on which I F is selected. When the inpiit signal is less than 2.5 MHz, the LO is tuned to into the IF. produces an I F signal centered in the IF passband. Normally the LO frequency is
101.5 MHz and the input passes directly
The Measuring Receiver can be automatically or manually tuned to the input signal:
In automatic tuning. the instrument searches for the presence spectrum. Once found, the LO is tuned of a signal over the entire input so that the signal is centered properly in the IF.
In manual tuning, the desired input frequency is entered via the numeric keyboard or kHz and kHz
4 properlv la the IF. so ft that a signal of that frequency would be centered
For both of these tuning modes, the LO can be configured to lock itself to an internal crystal oscillator
(for low-noise measurements) or signal centered in the IF). to track the input signal as it drifts (keeping the down-converted
The four tuning modes are listed below:
0
Automatic Tuning; Low-noise LO
Automatic Tuning; Track Mode,
Manual Tuning; Low-noise LO, and
Manual Taning; Track Mode.
Automatic Tuning-Low-Noise LO.
If not already tuned, the Measuring Receiver searches throughout its frequency range for an input signal. If two input signals have similar power levels, the higher frequency signal is usually selected.
The R F input signal’s second and third harmonic levels must be at least 10 dB below the level of the fundamental, and all other signals at the input must be at least 30 dB below the level of the dcsired signal. Once tuned, the LO is locked to an internal, voltage-controlled, crystal oscillator for highly-stable, low-noise measurements. Tuning is maintained
If the input signal disappears (drops below -20 to instrument powers-up.
-25 as long as a detectable signal is present. dBm). the Measuring Receiver initiates a signal search. This tuning mode is selected whenever Automatic Operation is pressed and when the
Ailtomatic Tuning-Track Mode.
The instrument searches for the inpiit signal in the same way as described in the previous paragraph: however, it does not lock to the internal reference oscillator. Instead, the LO is locked to the input signal itself and tracks it as it drifts. This fbnction is useful for checking modulation or level as a function of carrier frequency. If the input signal disappears (for example, when the LO switches bands) the Measuring Receiver searches for, and re-acquires the input signal. Track Mode tuning is not allowed with the 455 kHz IF or with input signals below 10 MHz. Track Mode tuning somewhat attenuates low-rate FM on the input signal: thus, FM measurements should only be made in track
3-141
Operation Model 8902A mode when modulation rates exceed 1 kHz. Also, Track Mode tuning is not recommended where optimum noise performance is required.
Manual Tuning-Low-Noise LO.
The instrument tunes is present, Once tuned, the stability and low noise. Once locked, tuning does not change unless a new frequency is entered,
Track Mode is selected, the tuning is stepped
4
Operation or Instrument Preset is selected. The manual tune mode is entered immediately when either MHt, kHz be used for tuned RF level measurements when used in conjunction with Special Function 32.9.l
Refer to Tiincd
9,
R F to the frequency keyed into it, via the keyboard, regardless of whether a signal
LO is locked to an internal voltage-controlled, crystal oscillator for high fi or kHz keys, Automatic or kHz is selected: or if Range Hold is selected. (Note that this tune mode can
LcwI
comment, “32.9 u p or down using the kHz
SPCL: Tuned RF Level Measurements Using Track-Mode
Manual Tuning-Track Mode.
The Measuring Receiver tunes to the keyed-in frequency in the same way as described in the previous paragraph. However, the LO is not locked to an internal oscillator; instead the LO is locked to the input signal itself and tracks it as it drifts. This fiinction is useful for measuring second or third harmonic signals and for tracking spurious signals.
PROCEDURE
Select FREQ.
Tune Mode Selection:
0
0
Select automatic tuning with AUTOMATIC OPERATION or AUTO TUNING (Blue Key,
TRACK MODE).
Select manual tuning with either MHz or one numeric entry), or with RANGE HOLD. of the kHz keys (with or without a preceding
0
Select track mode with TRACK MODE. (Return from the track mode to the low-noise mode, by selecting TRACK MODE again.)
Manual Tuning by Keyboard Entry:
To manually tune to a specific signal frequency, enter the frequency in MHz via the numeric keyboard, then press the MHz key.
The MHz key can also be used alone to aid in tuning: if the Measuring Receiver is tuned close but not exactly to the input signal, select MHz to center the signal in the tuning mode, and no signal is present, select MHz alone to tune the Measuring Receiver the Measuring Receiver tunes to 100 MHz.)
IF passband. If in automatic to the last frequency at which a signal was successfiilly tuned. (If no previous successfir1 tuning has been made,
RF Frequency Stepping:
To numeric keyboard, then press either kHz set to 0 kHz.)
.h or kHz
4. will change %e tuning by that step size each time the key is pressed. (At power-up, the step size is
This spccial function is not availablc with Grmwarc datc codcs 234.1985 and bclow. (To display thc Grmwarc datc codc. sclcct
42.0 SPCL.) To order a ROM set that contains this special function. contact the nearest HP sales oflice.
3-142
Model 8902A Operation
HP-IB PROGRAM CODES
When operating the Measuring Receiver via HP-IB, the units for the frequency steps can be either
Hz or kHz.
AUTO TUNING = AT
AUTOMATIC OPERATION = AU
Display Frequency
Display Increment =
Hz, Input Frequency Entry = HZ
MHz, Input Frequency Entry = MZ
Ranging Automatic =
RANGE
Step U p
HOLD G1
HU
=
FN
TRACK MODE off =
GO
Step Down (Hz) = H D
Step Up (kHz) = KU
Step Down (kHz) = KD
KO
TRACK MODE on = K1
COMMENTS
RF Frequency Stepping.
Using the kHz fi and kHz
4 a selectable frequency step (in kHz). This feature is most often used in conjunction with the frequency error function. The kHz keys can be used regardless of tune mode, but when pressed, the tuning mode reverts to manual tuning. If these keys are pressed in an automatic tuning mode, the instrument will tune tuning to the last successfully tuned frequency plus or minus the frequency step. Once a frequency step is entered on the keyboard (refer to “PROCEDURE”), pressing either of the kHz keys alone will change tuning by that step size until a new step frequency is defined. At power-up, the step size is zero.
HP-I8
R F frequencies can be changed in fundamental-units (Hz) steps via the possible from the front panel:
Hz Step U p = HU
Hz Step Down = H D
Tuning to Signals with Low-Rate, High-Deviation FM.
The instrument will not automatically tune to a signal that has low-rate, high-deviation FM. Use a manual tune mode to measure such signals.
Tuning to Signals with Narrow-Band FM and +M.
The automatic tuning, low-noise LO mode is adequate for most common measurements. It should always be used for measuring narrow-band FM and iPM.
Measuring Flatness as a Function of Carrier Frequency.
Automatic tuning, track mode is usefbl for measuring modulation or peak tuned RF level flatness as a function of carrier frequency. (Select Peak Tuned RF Level with Special Function 36.)
3-143
Operation Model 8902A
Tuning to Low-Level Signals.
Manual tuning, low-noise mode should be used with signals that may drop below the minimum threshold for automatic tuning. Manual tuning makes it possible frequency measurements on very low-level signals. to make tuned modulation and
Measuring Drift.
Manual tuning, track mode is useful for measuring drift on low-level signals in the presence of higher-level signals.
Determine Tuning Accuracy.
When manually tuning tuning accuracy. or frequency stepping, use the frequency error measurement to determine
Image Frequencies.
When the Measuring Receiver tunes to an input signal greater than 2.5 positions the internal equally well to within the IF a
LO passband. (For example,
MHz, the IF if the LO is at 101.5 MHz, signals at either 100 MHz frequency above the nominal tuning. The Measuring Receiver, however, will respond signal at the image frequency, that is, when the signal frequency minus the or 103
LO is
MHz
(the image) generate a 1.5 MHz IF.) When the instrument is tuned to an image, measurement errors may result with no Error Message displayed. (The input frequency measurement will always be in error. For FM and @M measurements, the Peak+ and Peak- functions are reversed. One way this problem is to step the tuning down by twice the
RF Level does not apply.)
IF to solve frequency, or let the instrument automaticaily tune. The following IF response plot illustrates the image passbands for each IF frequency. (Tuned
\ /
1.5 MHz IF
\ /
200 kHz
-120 kHz
455 kHz IF
1
(LO -455 hHz1
NOMINAL
TUNE0 FREOUENCY
LO I t 0 4 5 5 kHz1
IMAGE
FREIlUENCY (LO
-
1.5 M H d
NOMINAL
TUNEOFREQUENCY
LO ILO +1.5 M H d
SIGNAL
IMAGE
455 kHz und 1.5 MHz
IF Passband
Rerpon.w.3
3- 144
Model 8902A Operation
When Measuring Frequency Agile Sources or Multiple Signal Sources.
Whenever tuning to signals less than 2.5 MHz, the input signal passes directly into the IF. The is used
101.5 MHz, a passband is created from problem, manually tune the LO so
99
SPCL)
LO only to turn on the mixer. However, since the Measuring Receiver arbitrarily sets the LO to to 104 MHz. If this frequency band causes a measurement the passband for the down converted signal falls in an unoccupied region of the input spectrum. This method is not a preferred way to make measurements, but it might enable you to make some desired measurements. Note that when using this method you should disable Error 01 (by selecting 8.1 to prevent the Measuring Receiver from trying down-converted signal rather than the signal that is less than 2.5 MHz. to tune to a
Frequencies Greater Than 10 MHz.
When making measurements on inputs with frequencies greater than 10 MHz, signals present at the input that are less than 2.5 MHz pass directly into the removed by inserting the RF input high-pass filter. (Refer to
IF. These low-frequency signals can be
Filters, R F and IF
Searching for a Signal.
When manually tuning, often the exact input frequency is unknown. If during tuning, Error 01
(signal out of IF range) switch to
IF displayed, select the MHz key alone to center the signal in the IF. Also, if
LEVEL. (Refer to
IF
Levd
When the IF level rises significantly,
FREQ ERROR and enter the displayed value as a frequency step and complete tuning using the kHz keys. is searching fora signal using the kHz keys, it is best to search down from above the signal frequency while monitoring
Default Conditions.
When the Instrument Preset key is pressed, or on power-up, the Measuring Receiver selects the automatic tuning, low-noise LO mode.
Responding to Frequency Changes.
Using the automatic tune mode, the Measuring Receiver might not retune when the frequency changes, but its spectrum still has suffcient power within the tuned passband of the Measuring
Receiver's RF INPUT. It will appear that the carrier simply changed its level. If the instrument does not retune, frequency and level measurement results might not be as expected. Use a manual tune mode, if possible, in the following situations:
0
0
When working with frequency agile sources (such as frequency synthesizers) that have a frequency hopping function.
When changing frequency in harmonic steps.
3-145
Operation Model 8902A
Extending Tuned Measurements Below 2.5 MHz.
Use the following procedure to extend the range of tuned measurements below 2.5 MHz.
Only llic 455 kHz IF can he sclc~c-ld. monitoring
NOTE c*onnec?ors. minimum inpiit ficqiiency is 795 kH=. Mcasirrcmcnt accirracy may hc ckgradcd. I F signal may appear a1 the modillation
1. Select lNSTR PRESET (Blue Key, AUTOMATlC OPERATION).
2. Set the signal source to a carrier frequency between 3 and 9 MHt and to the level of the intended measurement.
3. Connect the signal source to the Measuring Receiver’s INPUT (or to a properly connected sensor module). Allow the Measuring Receiver to tune to the input signal.
4. Select RANGE HOLD. Select DISABLE ERROR (Blue Key, RANGE HOLD).
5. Enter the frequency value of the input signal and retune the signal source to that frequency.
6. Select the desired measurement mode. (RANGE HOLD and DISABLE ERROR can be released at this time. RANGE HOLD must be released for Tuned R F Level.)
3-146
Model 8902A Operation
RF Frequency Error
FUNCTIONS
FREQ ERROR
DESCRIPTION
The Frequency Error function enables the Measuring Receiver to measure the difference (in between the RF input signal frequency and the frequency function can be used to observe frequency drift against a keyboard-entered reference. of to kHz) which the instrument is tuned. This input signals, or to compare input frequencies
Display resolution is controlled by Special Function 7. (Refer to RF Freqirency Rcsolirlion on page
3-157.)
PROCEDURE
To make the RF frequency error measurement, connect the RF signal to the Measuring Receiver’s
RF INPUT.
If a frequency driA measurement is to be made, first allow the Measuring Receiver to automatically tune to the signal, then select the MHz key to prevent retuning. Select FREQ ERROR (Shift, FREQ) to display the frequency error. As the signal drifts the display indicates the magnitude and direction of the drift.
To make a frequency comparison, enter the reference frequency (in MHz) on the keyboard, then select MHz. Select FREQ ERROR to display the difference frequency. The number is negative if the signal frequency is lower than the reference, and positive if the signal frequency is higher than the reference. Valid frequency error measurements are made as long as the down-converted signal remains in the IF passband. (Refer to Timing
EXAMPLE
To measure the error of an oscillator designed to operate at 30 MHz, connect the oscillator’s output to the Measuring Receiver’s RF INPUT connector and select the following keystrokes:
LOCAL
(keystrokes)
(program codes)
5
L T -
Function
Measurement
3-147
Operation Model 8902A
HP-IB
PROGRAM
CODES
FREQ ERROR
MHz = MZ
= S5
MEASUREMENT TECHNIQUE
When the Measuring Receiver is tuned, the IF signal is amplified and limited. If manually tuned, the
RF input frequency is measured and compared to either the keyboard-entered frequency or to the frequency measured after the MHz key is pressed. The frequency difference is displayed as frequency error.
If the Measuring Receiver is automatically tuned, two methods of determining frequency error are used:
0
When the input signal is greater than 2.5 MHz, the frequency of the actual IF signal is subtracted from the selected IF frequency (455 kHz or 1.5 MHz) to determine the frequency error,
0
When the input signal is less than 2.5 MHz, the input signal is passed directly into the IF without down-conversion. When the signal is first located, the frequency is counted. When the
FREQ ERROR error. key is selected, this first-counted frequency becomes the reference. Subsequent frequency counts are subtracted from this reference, and the results are displayed as frequency
10 dB
ATTENUATOR RF AMP FIf.ER
INPUT
IF IF
ATTENUATOR INPUT AMP/FILTER LIMITERS
COUNTER]
CONTROLLER
VOLTMETER
AND DISPLAY
HRtlRtlRRfltl LW]
3-148
RF Frrqiicwcy Error Mcwsitrc)rnent Ulocl< Diugrum
COMMENTS
Down-Converted Signals.
The down-converted RF input frequency milst fall within the passband of the IF being used. For the 1.5 MHz IF, the passband is approximately approximately 200 kHz wide.
3 MHz wide. For the 455 kHz IF, the passband is
Model 8902A Operation
Input/Output Status.
When the instrument is measuring frequency error, the output signal available at MODULATION
OUTPUT/AUDIO INPUT is the same as for the last modulation measurement (as indicated by the
MODULATION OUTPUT annunciator).
Relative Measurements.
If frequency error is to be displayed relative to a reference, enter the value as a ratio reference using
the RATIO key. (Refer toRatio on page 3-245.)
Use Manual Tuning for Best Measurements.
The frequency error fiinction can be used with the automatic tuning low-noise LO tune mode, but it is most valuable when used with manual tuning (normal or Track Mode). It is not recommended that frequency error be used when in automatic tuning track mode, since an inherent tuning offset exists in this mode.
Step Frequency Aids Multi-Channel Measurements.
Check channel accuracy on multi-channel transmitters using the frequency error fiinction in conjunction with the kHz t and kHz keys. Set the step frequency to the channel spacing to quickly determine the accuracy of evenly-spaced channels.
LO in Image Passband Distorts Measurements.
When tuning manually, it is possible to accidentally adjust the LO passband; for example, when using the kHz .h and kHz
4
so that the input falls in the image keys. Frequency error measurements are inaccurate when the input image enters the IF passband. Refer to R F Freqirmcy
for an illustration of the image passbands.
Tuning
Changing Resolution.
Nwmally, the counter updates the display five times each second. For selection of other resolutions, use Special Function 7. (Refer to Rt;' Frqi/cncy reference accuracy *3 counts.
Rcsohtion
Counter accuracy is the
Input/Output Status.
When the Frequency Error function is selected, MODULATION OUTPUT/AUDIO INPUT continues to output the last-selected modulation signal, filtered and/or de-emphasized (except PRE
DISPLAY) as previously selected. The calibration of this output depends on the input signal level and should be assumed only when all errors are enabled (Special Function 8.8).
Parts Per Million Display.
To display frequency error in parts per million (ppm), first display the frequency error, then enter
1/10 the reference frequency (in MHz) the frequency error in parts per million. as a ratio reference, and select RATIO. The display shows
3-149
Model 8902A Operation
IF Frequency
FUNCTIONS
Special Function 34 (IF Frequency)
DESCRIPTION
The Measuring Receiver makes tuned (down-converted, heterodyned) measurements on its R F input signal using one of two IF frequencies, Three combinations of tuning and IF selection are used:
1. When RF input signals less than 2.5 MHz are measured, the RF input signal passes directly into the IF without down-conversion; that is, the RF input frequency and the IF frequency are the same. (Tuned measurements can be manually extended below 2.5 MHz. Refer to
Timing
RF
Frcqircwcy
2. When R F input signals greater than 2.5 MHz, but less than down-converted
Level measurements; irrespective of RF frequency.)
10 MHz are measured, the signal is to a 455 kHz IF. (The 455 kHz IF is also selected when making the Tuned RF
3. When RF input signals greater than 10 MHz are measured, the signal is down-converted to a
1.5
R F
MHz IF. (Note that special Function 3 can be used to select the 455 kHz IF. Refer toFi//m, and IF
Special Function 34.0 enables the Measuring Receiver to measure and display the IF frequency the signal being measured. for
PROCEDURE
To measure the IF frequency, key in 34.0 SPCL.
MEASUREMENT TECHNIQUE
The IF signal, generated when the Local Oscillator and the R F input signal mix, is amplified by the IF
Amplifier and FM either the 455 kHz
Limiters and then counted. The is displayed when Special Function
34 is used. When measuring RF inpiit frequencies greater than 2.5 MHz, the Measuring Receiver uses or 1.5 MHz IF. not normally used and the RF
For RF
IF frequency input frequencies less than input signal passes directly into the IF.
2.5 MHz, down-conversion is
3-151
Operation
BLOCK DIAGRAM
VOLTMETER
AND DISPLAY
Model 8902A
COMMENTS
Input/Output Status.
When the instrument is measuring IF frequency, the signal at MODULATION OUTPUT/AUDIO
INPUT remains unchanged.
Relative Measurements.
If IF frequency is to be displayed relative key. (Refer to Ratio
to a reference, enter the ratio reference using the RATIO
Frequency Resolution.
Normally, the counter updates the display five times each second. use Special Function 7. (Refer to RI: k'rc~yiicwy Rew/ii/ion
reference accuracy zt3 counts.
For selection of other resolutions,
Counter accuracy is the
IF Filter Selection.
IF filter selection is dependent on the selected IF Frequency. (Refer to F-il/cv'.$, RI.' und If: on page
3-259.)
When using the 455 kHz IF on input signals with
(that is, AM due to FM) increases substantially. freqtrencies greater than 300 MHz, incidental AM
RF Input Frequency Calculation.
The Measuring Receiver determines the frequency ofthe of both the IF and LO and calciilating their difference.
RF input signal by counting the frequencies
IF Frequency Accuracy.
The IF frequency need not be exactly its nominal value in order to guarantee accurate modulation measurements. Unless specifically overridden by Special Function 8 or DISABLE ERROR (Blue
Key, RANGE HOLD), Error Messages safeguard the measurements. (Refer
and RI: f:rc.cliccwc'y Tiiuiiig on
to l3'ror
Messuge
Disahlc~
3- 152
Model 8902A Operation
LO Frequency
FUNCTIONS
Special Function 33 (LO Frequency)
DESCRIPTION
Special Function 33.0 enables the Measuring Receiver to display the local oscillator (LO) frequency.
PROCEDURE
To measure the LO frequency, key in 33.0 SPCL.
MEASUREMENT TECHNIQUE
The LO frequency is essentially measured directly by the counter. The frequency that the LO is tuned to depends on (1) whether automatic tuning or manual tuning is being used, (2) whether the RF input signal is being down-converted, and tuning. (Refer to
RF
Freqircmy
(3)
Timing which IF is being used. The following table summarizes
on page 3-141 for more information.)
LO
Tuning
Mode
Automatic
Manual
Down
Conversion
Yes
Yes
N o
Yes
Yes
No
Selected
IF
1.5 MHz
455 kHz
1.5 MHz
1.5 MHz
455 kHz
1.5 MHz
Approximate
LO Frequency
Input
Input
+
IF
IF
101.5 MHz
Keyed In
Keyed In
101.5
+
IF
IF
MHz
3- 153
Operation
BLOCK DIAGRAM
Model 8902A
COMMENTS
Input/Output Status.
When the instrument is measuring the LO frequency, the signal at MODULATION OUTPUT/
AUDIO INPUT remains unchanged.
Relative Measurements.
If the LO frequency is to be displayed relative to a reference, enter the value as a ratio reference using the RATIO key. (Refer to Rulio
Display Resolution.
Normally, the counter updates the display tive times each second. For selection use Special Function 7. (Refer to reference accuracy k3 counts.
RI.'
l ~ r ( i q i / ~ ~ n c y
Cou of other resolutions. titer accuracy is the
LO Does Not Phase Lock to INPUT.
In general, LO tuning is never exact but does not phase lock to the is
RF input signal. close enough to give calibrated measiirements. The LO
LO Frequency for INPUT Less Than 2.5 MHz.
When the RF inpiit signal is less than 2.5 MHz, the is arbitrary.
Note that 101.5 MHz is the frequency the LO is set to for a 100 MHz RF input signal with an IF of
1.5 MHz.
LO frequency is set to 101.5 MHz. This frequency
The LO must remain on to allow the RF input signal to pass through the input mixer.
3- 154
Model 8902A
LO Input and LO Output (Option 003)
Operation
Do not apply greattv than 40 Vdc or +S dllm oj’RFpowcr into thci LO INPUT
or damagc) to the insfrirmcnt may result. Do not apply dc volragc or RF power into Ihr LO OUTPUT or damage to the insfriimcnl may rcsirlt.
DESCRIPTION
In Measuring Receivers with Option the rear-panel LO OUTPUT and LO
003, the internal local oscillator
INPUT connectors. The range of
(LO) signal is the LO signal routed through is 1.27 MHz to
1301.5 MHz, at approximately 0 dBm. Both connectors are 500, ac-coupled, Type-N connectors.
NOTE
The rt.ar-punc4 LO OUTPUT rnrrsl be connccfrd IO fhr rear-panel
LO
INPUT fior normal Mcuutring Rcwivc>r opcrafion /ha/ itsc1.s thc internal local oscillator.
BLOCK DIAGRAM
10 dB
ATTENUATOR RF AMP
INPUT
IF AMP
LO Inpiif and LO Oitfpicl Block Diagram
3- I55
Operation Model 890214
PROCEDURE
To use LO OUTPUT as a signal source:
1. Select an IF frequency of either 1.5 MHz or 455 kHz using Special Function 3. (If the frequency is not specified, the Measuring Receiver will assume the 1.5 MHz IF for keyboard- entered frequencies greater than 10 MHz and the 455 kHz IF for frequencies less than 10 but greater than 2.5 MHz.)
IF
MHz
2. Subtract the IF frequency from the frequency desired at LO OUTPUT, and enter the result, in
MHz, via the numeric keys; then press the MHz key. (To tune the LO below 2.96 MHz, use the procediire as described, but select the 455 kHz IF using Special Function code 3.1, and disable
Error 01 using Special Function code 8.1.)
3. Connect the LO OUTPUT to the desired input.
The LO frequency can be monitored using Special Function 33. (Refer to
3-153.)
LO
Frccpc~ncy o n page
To use an external source as the LO INPUT:
1. Select an IF frequency (1.5 MHz or 455 kHz) using Special Function 3.
2. Press the MHz key to enter manual tune mode (to prevent the internal LO from continuously tuning).
3. Add the IF frequency to the frequency to which the Measuring Receiver is to be tuned, and set the external LO to that frequency.
4. Adjust the external LO to 0 dBm and connect it to the LO INPUT.
COMMENTS
Using the LO OUTPUT.
LO tuning is not exact. The instrument tunes the LO only close enough to make calibrated measurements.
Using the LO INPUT.
To tune to inputs below 2.5 MHz with an external LO, select the 1.5 MHz IF, but set the LO to approximately 100 MHz. LO signal is required for the Input Mixer to function even when down-conversion is not desired.
Invalid Frequency Measurements (RF and LO).
When an external invalid. used.
LO is used, measurements made using the FREQ or FREQ ERROR keys are
To determine input frequency, subtract the 1F frequency (34.0 SPCL) from the LO frequency
The LO frequency function (33.0 SPCL) continues to measure the internal LO.
FM Transients Using an External LO.
When using an external LO, rapid changes in IF passband cause FM transients. Several seconds are then required before accurat.e measurements are possible. To avoid the problem, turn off the external LO
LO frequency within the when switching its frequency.
3-156
Model 8902A Operation
RF
Frequency Resolution
FUNCTIONS
Special Function 7 (RF Frequency Resolution)
DESCRIPTION
When making RF measurements, the frequency resolution can be manually set using Special
Function 7.
When RF frequency measurements are made, the Measuring Receiver normally updates the display five times each second. The instrument automatically selects approximately
320 MHz;
2.5 and 1000
(A resolution of 0.1
Hz
Hz
100 Hz
10 Hz resolution for frequencies below resolution for frequencies from approximately 2.5 to approximately resolution for frequencies greater than approximately 320 numeric keyboard and the or 1 Hz can be selected for RF frequency measurements.)
MHz. Use
SPCL key to set the frequency resolution to either 1000. 100, or 10 the
Special Function 7
IF Frequency, and LO the measurement resolution for RF Input Frequency,
Frequency Measurements.
RF Frequency Error,
PROCEDURE
To set the fieqiiency resolution to a selected range or to re-enter the automatic selection mode, key in the corresponding Special Function code, then time increases.)
SPCL:
7.0 Automatic selection.
7.1 Resolution of 10 Hz.
7.2 Resolution of 100 Hz.
7.3 Resolution of I kHz.
7.4 (Applies to RF
Resolution of 0.1
10.1 MHz through
Frequency measiirements only; other measurements treat 7.4
Hz for input signals less than 10.1 MHz; resolution of
MHt. (When measuring frequencies time with this resolution is approximately 20 seconds.) as
1 high as 1300
Hz for signals from
MHz, as 7.1.) measurement
COMMENTS
Change Resolution Any Time.
The Measuring Receiver need not. be making RF frequency measurements in order to change resolution modes; however, the resolution mode only affects
Counter accuracy is the reference accuracy +3 counts.
RF frequency-related measurements.
RF Frequency Measurements Greater Than 20 GHz
When making RF frequency measurements greater than 20 GHz, 7.1 SPCL selects 100 Hz resolution.
This spccial function is not availablc with firmwarc datc codcs 234.1985 and below. (To display the firmwarc datc codc. sclcct
42.0 SPCL.) order a ROM set that contains this spcdal runction. contact thc ncarest HP salcs orficc.
3-157
Model 8902A Operation
Modulation Measurements Contents
AM
AM
.......................................................................................................
3-161
0
How
..............................................................................
.3-I65
0
0
0
AM Output
0
How
How to
How to optimize AM ALC response time vs. modulation rate.
...........................................................................................
...............................................................................................
How to use the rear-panel AM OUTPUT to obtain demodulated AM.
3- 167
3- 173
FM
FM
........................................................................................................
3-177
0
How
........................................................................................... 3- 18 1
0
How
.........................................................................................
3-1 87
0
FM Output..
.............................................................................................
0
How to use the rear-panel FM OUTPUT to obtain demodulated FM.
0
.3-191
.................................................................................... .3- 193
How to set up the instrument to output demodulated squelch-tone bursts. cPM
.......................................................................................................
0
How to measure QM deviation.
3-197
AUDIO DETECTORS
Audio Detectors ..........................................................................................
Audio Detector Response.
0
How to trade
............................................................................... off readability of noisy signals for measurement time.
3-20 1
.3-205
GENERAL MODULATION MEASUREMENT FUNCTIONS
Audio Filters..
0
Audio Range..
...........................................................................................
...........................................................................................
How to vary the display resolution and MODULATION OUTPUT sensitivity.
.3-207
.3-21 I
........................................................................ .3-2 15
0
0
Residual Noise Effects
0
How to use the MODULATION OUTPUT/AUDIO INPUT to obtain the demodulated, audio signal.
How to use the MODULATION OUTPUT/AUDIO INPI JT to input an external audio signal for audio analysis.
How to
................................................................................... account for noise to make the most accurate peak-modulation measurements.
.3-2 19
3- 159
Model 8902A Operation
AM
FUNCTIONS
AM, Special Function 2 (Audio Range)
DESCRIPTION
Selecting AM enables the Measuring Receiver to measure the AM depth of the tuned R F input signal.
(Selecting Special Function 2 sets measurement limits on the range of AM depth at the same time a specific display resolution is set.)
AM measurements are specified for rates from 20 below
10
0.5 to
(or
Hz to 260 to whenever the
MHz (1.5
455
MHz IF
15 kHz for carriers kHz for kHz IF is used) and from 20 Hz to only). The corresponding
10 MHz and below
Hz
(or to 10 kHz for carrier frequencies
3 with the carriers from 10 to 1300 MHz (1.5 MHz
100
455
10 MHz and kHz IF) and approximately 0.5 Hz
IF only). (Special Function 6.1 will modify the lower frequency.) Modulation depths to 99% can be measured. kHz for carrier frequencies from dB audio bandwidths are approximately
The demodulated signal's frequency and distortion can mcnfs
section which starts on page 3-225.)
also be measured. (Refer to A irdio Mcasirrc-
PROCEDURE
To make an AM measurement, first tune the instrument to the input signal by selecting AUTO-
MATIC OPERATION. Select AM.
Select an audio detector: PEAKS, PEAK-, PEAK&/2, AVG, or RMS. The RMS detector (Blue
Key, AVG) is less accurate than the other detectors in measuring AM, has a reduced bandwidth, and is typically only used for audio distortion measurements.
The following table lists the different measurement range limits that can be selected with Special
Function 2:
Modulation
Range
Peak2 (W)
Detector
Selected
Automatic Selection
1 4 RMS
140
540
Pk, Avg
Pk, Avg, RMS
1100 Pk, Avg, RMS
Special
Function
Code
2.0 SPCL
2.4 SPCL
2.4 SPCL
2.1 SPCL
2.2 SPCL or
2.3 SPCL
Program
Code
2.0SP
2.4SP
2.4SP
2.1 SP
2.2SP or
2.3SP
Display
Resolution
(O/O)
MODULATION
OUTPUT
Sensitivity
(Vat/% AM)
Automatic Selection
0.001 0.1
0.01
0.01
0.1
0.1
0.1 0.01
Tq filter the dernodiilated signal, select the desired filter. (Refer to I.'i//cm, A irdio for more information about filters.)
3-161
Operation Model 8902A
EXAMPLE
To measure the positive peak AM depth of a signal in a 50 bandwidth:
Hz to 15 kHz demodulated signal
LOCAL
(keystrokes)
’I r
I.] czLn:6sk13 Em
(program codes)
Measurement
T
7
Detector
Filters
HP-18 PROGRAM CODES
All HP-IB codes for setting a limit or ments are provided in “Procedures”. a specific display resolution for modulation-depth measure-
AM = MI
SPCL = SP
MEASUREMENT TECHNIQUE
The AM Demodulator rneasitres AM as a ratio of the demodulated audio signal level tuned carrier level. An automatic level control (ALC) loop within the AM Demodulator holds the carrier level constant so that the percent AM is proportional to to the average the peak amplitude of the demodulated audio output. This audio output is then filtered, audio detected, and displayed as
96 AM. The demodulated AM is available at MODULATION OUTPUT/AUDIO INPUT (unless
AUDIO INPUT is selected).
AUDIO
<
[
AUDIO
1-1
VOLTMETER
A
M
Mcja.siirc>mc~nl
3-162
Model 8902A Operation
COMMENTS
Input/Output Status.
The demodiilated AM is present at MODULATION OUTPUT/AUDIO INPUT (unless AUDIO
INPUT has been selected). The demodulated AM is usually present at the rear-panel AM connector. (Refer to AM Oiitpirl
OUTPUT
PeakflP Detector.
The PEAK+ detector always detectsthe peak of the carrier envelope while the PEAK- detector always detects the trough. The PEAKzt/2 detector sums the peak and the trough readings and divides the total by two to provide an average of the two peak values. with the detected average value.)
(Do
Automatic Range Selection.
The routine which automatically selects the modulation range contains a region of overlap between
35 and 40°/o AM (peak detected). When using the average or RMS detectors, ranging occiirs at readings lower than these. In general, if the modulation is reduced from above 40% into the
To only 0.1% resolution is ordinarily displayed although 0.0 1% resolution is available. display the increased resolution, press the AM key a second time. Audio Range has more detailed information on the modulation ranges that can be set.
Automatic Filter Selection.
When operating above 2.5 MHz, while using the 455 kHz IF, the upper limit signals modulation rate is that of the >20 when operating below 10 MHz or kHz LP Filter. The 15 kflz whenever the 455 IF
LP
Time
Filter
is of
the demodulated automatically selected is selected. However, this filter may be overridden by selecting another LP Filter. The lower limit of the modulation rate is determined by the ALC response time selected. (Refer to AM ALC Rcsponse
Inverted Output Signal.
The signal at the rear-panel AM Output is inverted relative to the Modulation Output signal.
Potential Inaccuracies.
AM conditions that cause the carrier signal to disappear (such as 1000/0 AM
05 (FM squelched) to be displayed when these measurements are selected. or pulse modulation) will cause inaccuracies in measurement of FM, RM. or input frequency, or they could cause Error
Increased Accuracy.
Accuracy of AM readings may be improved by calibrating the AM measurement (refer to AM
Cc’lihralion on
and by taking into account the effects of residual noise (refer to Rt.sidira/
Noisc EjJ2ct.s on
Relative AM Depth Measurements.
If AM depth is to be displayed relative to a
RATIO key. (Refer to Ratio
reference, enter the value as a ratio reference using the
3-163
Model 8902A Operation
AM ALC Response Time
FUNCTIONS
Special Function 6 (Automatic Level Control)
DESCRIPTION
The Measuring Receiver normally uses a slow-responding AM automatic level control (ALC) circuit, allowing AM rates as low as 20 Hz to pass unaffected by the leveling loop. (Refer to the figure in
AM, “Measurement Technique.”)
Select a fast ALC response time to speed up the measurement settling time required for varying carrier levels. The faster ALC response time degrades AM accuracy at rates less than 1 kHz.
The ALC can be disabled. This feature, used in conjunction with the rear-panel AM Output connector, is useful for measuring AM at very low modulation rates. Disabling the ALC also permits measuring absolute changes in depth without regard to changes in carrier level (a feature that is useful in characterizing amplitude modulators).
PROCEDURE
The instrument normally operates with a slow AM ALC response time. time,
To change the response or to disable the ALC, enter the corresponding Special Function code, then select SPCL. r
~~
~~
AM ALC
Response
(AM
Fast ALC rates >1 kHz
~
ALC off
I
I
Special
Function Code
6.0 SPCL
6.1 SPCL
6.2 SPCL
I
I 6.0SP
6.1SP
6.2SP
I
HP-IB PROGRAM CODES
For HP-IB codes. refer to “PROCEDURE”.
COMMENTS
Default Condition.
When the instrument is first turned on, or when Automatic Operation selected, the slow ALC response is selected. or Instrument Preset is
IF Level Dependency.
The displayed modulation depth and the sensitivity of the Modulation Output connector for AM demodulation are incorrect when the ALC is disabled unless the
1F level is 1000/0. (Refer to
I F
Idcvc~I
3-165
Model 8902A Operation
AM Calibration
FUNCTIONS
CALIBRATE, SAVE CAL, Yo CAL FACTOR, Special Functions 13 (AM Calibration) and
Calibration Factors).
16 (AM
DESCRIPTION
The accuracy of the Measuring Receiver's AM demodulator can be checked with the internal
AM calibrator. The calibration process generates a calibration factor to compensate for the AM measurement error (within the accuracy limits of the AM Calibrator). Using the SAVE CAL key
Special Function 16, the calibration factor can then be enabled to or automatically correct the measured
AM error in subsequent measurements. With the calibration factor enabled, AM measurements can be made with an accuracy typically better than 0.5%. The calibration factor can be enabled, disabled, or displayed at any time.
Other instruments in the HP 8901 checked using Special Function 13. and 8902 R F signal analyzer family can be calibrated or cross
PROCEDURE
Self-calibration
To determine the measurement error of the Measuring Receiver's AM demodulation circuits, first a half-hour continuous operation before calibration, then perform the following steps:
1. Connect the CALIBRATION AM/FM OUTPUT to the RF INPUT with a sensor module with an internal switch such as the HP I1722A) and select AM.
50R cable (or a
2. Select CALIBRATE. After several seconds, the AM calibration factor is displayed in %o and stored (but not enabled unless already enabled).
The instrument displays iOO.OOo/o if no error is measured. A display demodulator in the Measuring Receiver is reading 0.17% high. As long as the CALIBRATE key light is on and the cable is connected, calibration repeats and the AM calibration factor is updated approximately every 17 seconds. key.
To turn off of 100.17% the calibrator, select CALlBRATE or means the AM any Measurement
NOTE
For opiimirm acwracy, ihc> insirirmcnf should hc coniiriiroirsly opcrafing Jor
a!
kasi
one
hail' hoirr ht;/orc calihrafion is perlormod. In addilion, ihe Jirsi f wo A M Calihraiion I:aclors rcwivcd allcr insirirmcwi powcr-lip shordd no1 hc Jirlly sc>ffl.cl. no1 he iiscd cvcn ij'lhc inslrirmcnl is alwady warm, sincc ihc circuits in ihc audio chain may
Correcting Measurements with the AM Calibration Factor. Once a calibration factor has been determined, the instrument retains that value in its non-volatile memory. This factor may be enabled to automatically correct AM measurements. The calibration factor can also be disabled or displayed.
Selecting
O/o
CAL FACTOR or 16.2 SPCL displays the calibration factor being used.
3- 167
Operation Model 8902A
Enter the appropriate front-panel key or Special Function code to manipulate the AM Calibration
Factor as described in the following table:
Action:
AM Calibration
Factor
Measurement
Mode
Program Code
or
Special Function Code
Disable Any
AM
(From CALIBRATE mode)
16.0 SPCL
(Blue Key)
SAVE CAL
16.0SP
sc
Enable
Any 16.1 SPCL 16.1SP
Display
I
AM
I I
(Blue Key)
‘10 CAL FACTOR*
16.2 SPCL
I
CF
16.2SP
‘The 70 CAL FACTOR key displays the status of the calibration factor: The factor is enabled if the value of 1%. factor
A display of 100.00% would
Any is displayed, with 0.01% resolution. The factor is disabled if 100% of the is displayed. (Note the resolution
Calibrating or
Cross
Checking Another HP 8901 or 8902 RF Signal Analyzer
To compute an AM calibration factor for another RF signal analyzer that has no internal calibrator, or that has an internal calibrator that is to be cross checked, use the Measuring Receiver and its calibrator as follows:
1. Connect the Measuring Receiver’s CALIBRATION AM/FM OUTPUT to the R F input of the other R F signal analyzer.
2. Select 13.0 SPCL for the Measuring Receiver. Record the value that appears on the display.
This is the computed, calibrated, peak AM depth (excluding noise).
3. Select 13.1 SPCL for both instruments. Record the value that appears on the display of the RF signal analyzer. (If display jitter makes readings difficult, select 5.1 SPCL.) The displayed value is the weighted, peak, residual AM depth of the calibrator’s unmodulated output as demodulated by the R F signal analyzer.
4. Select 13.2 SPCL for both instruments. Record the value that appears modulated output. (If display jitter makes readings difficult, select 5.1 on the display
SPCL.) of the
R F signal analyzer. This value is the demodulated, positive, peak AM depth of the calibrator’s
5. On the R F signal analyzer, select PEAK-. the difference between the results of steps
Note the value displayed on the
4 and 5 is three counts
RF signal analyzer. If or less in the least significant digit, an average between the two need not be computed; use the result compute the average as follows: from step 4. If the difference between the two results is greater than three counts in the least significant digit,
(13.2 result) =
(result of step 4)
+
2(result of step 5)
3
6. Compute the AM calibration factor of the RF signal analyzer as follows:
AM Calibration Factor (%) = 100 x
(13.2 result) - (13.1
(13.0 result) result)
3-168
Model 8902A Operation
7. To use this AM calibration factor to correct AM measurements made with the R F signal analyzer, enter the value analyzer. as a ratio reference and use the Ratio fiinction in the R F signal
The Special Function codes are summarized in the table below:
I
Function
I I
Special
I
Program Code
Function
Code
13.0 SPCL 13.0SP
I
Display computed peak AM
Display demodulated peak residual AM 13.1 SPCL
13.2 SPCL
13.1 SP
13.2 SP Display demodulated peak AM
HP-IB
PROGRAM
CODES
HP-IB codes for enabling, disabling, or displaying the internnl :\hl calibration factor are provided in
“Procedures”. The HP-1B codes for the AM Calibrator Spcci:il Function used to calibrate another
R F signal analyzer are also provided as part of “Procedures”.
AM =
MI off =
CALIBRATE on =
SPCL = SP
CO
CI
INDICATIONS
Self-Calibration
When the CALIBRATE key is pressed, approximately 17 seconds pass during which the instrument configures itself and tunes to the calibrator’s signal. The display indicates four dashes (----) and lights the
O/o annunciator. Once the AM Calibration Factor has been computed, it is displayed.
Subsequent updates occur approximately every I7 seconds.
Correcting Measurements with the AM Calibration Factor (Self-Calibrated).
When the calibration factor is enabled, the AM depth measurement is always a corrected measurement.
If “10 CAL FACTOR (Blue Key, MHz) is selected, and the AM calibration factor is enabled, the
AM calibration factor is displayed. If
O/o
CAL FACTOR (Blue Key, MHz) is selected, and the AM calibration factor is disabled, loo‘#) is displayed. (Note the resolution of 1%)
Calibrating Another RF Signal Analyzer.
The Measuring Receiver displays the computed AM depth (Special Function dashes (--) throughout the rest of the procedure.
13.0). but shows two
MEASUREMENT
TECHNIQUE
When AM and then CALIBRATE are selected, the FM Calibrator sends an iinmodulated carrier to the AM Calibrator.
10.1 MHz
The AM Calibrator contains two identical modulators in parallel whose outputs are summed. When the calibration operation is initiated, each modulator is turned on and each individual output level is measured. via an on-board detector, to compiite A M depth.
3- 169
Operation Model 8902A
While one of the modulators is on, the residual AM of the calibrator (very low) and the demodulator (more significant) are characterized and weighted (refer to Residi/a/ N0i.w h''jkc/s
Next, one modulator is left on and the other
Since the near 33.33%. is toggled on and off at a 10 kHz
AM rate.
(The exact depth is derived from the measurements that characterize the individual modulators.) This modulation is then measured by the AM demodulator. (Both peak detectors are used, and their average is computed.) on
RF signal is switched between full on and half on, the resultant carrier modulation is very
The Measuring Receiver compares the modulation depth (static measurements) with the demodu- lated A M (toggled measurements) and computes its accuracy error as follows:
AM Calibration Factor (%) =
Demodulated AM -
Demodulated Residual
Computed AM
AM x 100
A11 segments of the calibration are carefiilly monitored. If any segment is out of limits, the calibration is aborted and Error 08 is displayed.
MODULATOR A ,BUFFER A
3-170
COMMENTS
Default Calibration Factor
If the instrument's non-volatile memory is erased, 100.OOo/o is used as the default calibration factor.
Updating the AM Calibration Factor
Whenever AM calibration is performed, the instrument updates the stored AM calibration factor.
Model 8902A Operation
Special Function Cancellation
Performing Calibration cancels most special fiinctions.
When Using the AM Calibrator to Calibrate Other Signal Analyzers
The modiilation waveform of the AM Calibrator is a rounded squarewave. An which uses it as preserve the full fidelity of the waveform.
RF signal analyzer, a calibration standard, must have demodulation and audio-processing circuits which
Automatic AM Ranging
When used to calibrate an RF signal analyzer, Special Functions 13.1 and 13.2 set the AM modiilation range to that the audio ranging
Key in 2.0 of 0
SPCL to is to
100% (Special Function 2.1). Upon exiting the AM Calibrator Special Function, not returned to automatic but remains fixed (thus leaving the SPCL light on). return the audio ranging to automatic.
3-171
Model 8902A Operation
AM
output
Do not apply greater than 10 Vpk (ac+dc) info the rear-pand A M
connecfor or
damage fo fhe insfriimenf may rtwlt.
OUTPUT
DESCRIPTION
The rear-panel AM OUTPUT (dc coupled, 10 for the display
AM of demodulated from the kn output impedance) provides an auxiliary output
RF input signal. This output enables monitoring of other measurements (such as FM, @M, or audio signals).
AM during
The output can also be used in conjunction with Special Function 6.2 (described in AMALC Rcsponse
Time
to measure AM depth at low modulation rates.
The output signal comprises both a dc voltage (related to the detected
(bandwidth 16 voltage (Vow kHz, one pole proportional to
IF level) and an ac voltage the AM depth). The dc component contains an offset which must be subtracted out. The relationship between at AM OUTPUT is:
Oh AM and the signal levels
% A M = lVdc -
I
x 100% where: Vpk is the peak of the ac component,
Vdc is the total dc component, and
Voff is the dc offset voltage.
When the AM ALC is on, the dc level at AM OUTPUT is held constant, thus,
% A M = K x Vpk, where:
When the AM ALC is turned off (Special Function 6.2), the dc voltage at AM
OUTPUT varies with the signal level (although the offset remains constant), and the full formula must be used for each measurement.
PROCEDURE
To measure AM depth via AM OUTPUT, first determine the offset voltage:
Select AUTOMATIC OPERATION to clear any Special Functions in effect, then connect a dc voltmeter to the AM OUTPUT connector and remove the tuning, and read the offset voltage on the voltmeter. any signal at RF INPUT. Press MHz to fix
Disable the AM ALC loop (6.2 peak ac signals at AM OUTPUT. Use the first equation in
RF INPUT. Measure the dc and
‘‘DESCRIPTION’’
Yo AM.
3- I73
Operation Model 8902A
EXAMPLE
To measure AM depth at AM OUTPUT with the AM ALC turned off, measure
Vof/
Remove any signal at the RF INPUT and connect a dc voltmeter to AM OUTPUT.
LOCAL
(keystrokes) gxmrnc
OPERATION
(program codes)
AUMZ
For this
RF INPUT the voltmeter reads an offset voltage of and tune the Measuring Receiver. Disable the
-0.36
AM
Vdc. Connect an
ALC by selecting
AM
6.2 signal
SPCL.
Measure the dc voltage at AM OUTPUT. (When low AM rates are used, it is easiest to measure the dc voltage at AM OUTPUT before the modulation is applied.) reads -0.46 Vdc. Measure the peak ac voltage at be necessary). For this example, assume 0.02 Vpk
AM
For this example, assume the voltmeter
OUTPUT (for low rates an oscilloscope may was measured on an oscilloscope. The 94.1 AM is:
% A M =
V’pk x lVdc
100%
-
- 0.02
((-0.46)
100%
-
(-0.36)l
= 20% AM
BLOCK DIAGRAM
r
AM
DEMODULATOR- AUOIO
(
L-MiOilVITI
AUDIO VOLTMETER
AM Orifpill Block Dingrctm
3-174
Model 8902A Operation
COMMENTS
Inherent IF Component
AM OUTPUT contains a significant IF component which is greatest when operating at a carrier of 150 kHz.
RF Peak Detector Measurements of AM Output
The accuracy of measurements made on the AM OUTPUT
35.0).
RF level
3-175
Model 8902A Operation
FUNCTIONS
FM, Special Function 2 (Audio Range)
DESCRIPTION
The Measuring Receiver can measure the FM deviation of the tuned input signal. (Special Function
2 enables the instrument to set limits on the range of FM deviation that can be measured.)
Hz to 10 kHz for carrier frequencies 10 MHz and FM Measurements are specified for rates from 20 below (or whenever the
Hz to 260 kHz for carriers from 10 to 1300 MHz (1.5 MHz IF only). Peak deviations up to 40 kHz can be measured on carriers below 10 MHz, and peak deviations up to 400 kHz can be measured carriers above 10 MHz.
455 kHz IF is used) and from 20 Hz to 200 kHz for carrier frequencies from
10 to 1300 MHz (1.5 MHz IF only). The corresponding 3 dB audio bandwidths are approximately
0.5 Hz to 15 kHz for carriers 10 MHz and below (or with the 455 kHz IF) and approximately 0.2 on
The demodulated signal's frequency and distortion can also be measured. (Refer to A irdio Measore- mcnts
PROCEDURE
To make an FM measurement, first tune the instrument to the input signal by selecting Automatic
Operation. Press the FM key.
Select an audio detector: PEAK+, PEAK-, PEAKzt/2, AVG, or RMS. (The RMS detector, selected by pressing the Blue Key and AVG key, is accurate in measuring FM, has a reduced bandwidth, and is usually only used for less audio distortion measurements.)
3- 177
Operation Model 8902A
The following table lists the different measurement range limits that can be selected with Special
Function 2
Modulation
Range
(PeakkkHz dev.)
Detector
Selected
Automatic Selection
10.04 RMS
10.4
14
Pk,
RMS
Pk, Avg
Avg, RMS
Pk,
Pk,
Pk, Avg
Avg,
Avg,
RMS
RMS
540 Pkt Avgt RMS
1400 Pk, Avg, RMS
Special
Function
Code
2.0 SPCL
2.4 SPCL'
2.4 SPCL
2.4 SPCL1
2.1 SPCLl
2.4 SPCL
2.1 SPCL
2.2 SPCL1
2.2 SPCL
2.3 spcL1
2.3 SPCL
Program
Code
2.0SP
2.4SP
2.4SP
2.4SP
2.1SP
2.4SP
2.1SP
2.2SP
2.2SP
2.3SP
2.3SP
Display
Resolution
(W
MODULATION
OUTPUT
Sensitivity
(Vat/% Hz)
Automatic Selection
0.01 1 00
10 0.1
~~
1 1
10
100
0.1
0.01
To filter the demodulated signal, press the appropriate filter keys. (Refer to Filters, A iidio
207 for more information about filters.) If de-emphasis equalization is desired, select the appropriate time constant and display placement. (Refer about filters.) to FM Dr-emphasis
for more information
EXAMPLE
To measure the positive peak deviation of a signal in a 50 Hz to 15 kHz post-detection bandwidth and to place a 750 ps time constant de-emphasis before the display:
LOCAL
(keystrokes) r
FILTERS FM D E - E M W l S
1
(program codes)
Measurement
L'J-LL
Detector Filters
FM De-emphasis
3-178
Model 8902A Operation
HP-IB PROGRAM
CODES
All HP-IB codes for setting range limits for FM measurements are provided in “Procedures”.
FM = M2
SPCL = SP
MEASUREMENT TECHNIQUE
The FM on the IF is demodulated by a frequency discriminator. The amplitude and displayed as kHz deviation. of the discriminator’s output is proportional to the frequency deviation. The demodulated signal is filtered, audio detected,
FM de-emphasis equalization can be inserted ahead selecting PRE DISPLAY. The demodulated FM of the audio detectors and display circuitry by signal always passes through the FM de-emphasis
“network’’ before it appears at the output of MODULATION OUTPUT/AUDIO INPUT.
COMMENTS
Input/Output Status.
The demodulated FM is present at MODULATION OUTPUT/AUDlr) INPUT (unless AUDIO
INPUT has been selected). The demodulated FM is usually present at the rear-panel FM OUTPUT connector. If the is automatically squelched (muted, turned on) except
RF input signal drops too low for accurate FM demodulation, the FM measurement for the FM OUTPUT. (Refer to FM Oiifpirt
Relative FM Deviation Measurements.
If FM deviation is to be displayed relative to a reference, enter the value as a ratio reference using the RATIO key. (Refer to Ratio
3- 179
Opera tion Model 8902A
Peak&/P Detector.
The PEAK+ detector always detects the upward carrier frequency excursion while the PEAK- detector always detects the downward carrier frequency excursion. The PEAKf/2 detector slims the upward and downward frequency-excursion readings and divides the total by two to provide an average of the two peak values. value.)
(Do not confuse this “average” value with the detected average
Inverted Output Signals.
When operating with carrier frequencies below 2.5 MHz, the output signal at MODULATION
OUTPUT/AUDIO INPUT is inverted unless the 455 kHz frequencies above 2.5 MHz or when using the 455
IF is selected. When operating with carrier kHz IF, the signal at FM OUTPUT is inverted.
Automatic Range Selection.
The routine which automatically selects the modulation range contains regions of overlap between the following displayed peak deviations:
0.35 and 0.4 kHz (750 pus de-emphasis, pre-display only), 3.5 and 4 kHz, and 35 and 40 kHz.
When using the average or RMS detector, ranging will occur at readings lower than these. In general, if the modulation is reduced from a higher range into an overlap region, the range does not change.
To range the display for increased resolution, press the FM key a second time. To set the instrument to a selected modulation range, refer to Audio Range.
Default Condition.
When the Measuring Receiver is first powered up, demodulated FM, with a sensitivity of
Vpk/MHz (400 kHz peak deviation range), is available at MODULATION OUTPUT/AUDIO
INPUT. The instrument does not autorange to more sensitive ranges because the Frequency
Measurement mode has been automatically selected, which automatically disables Error circuits overdriven). When Error ranges.
04
04
0.01
(audio is disabled, the instrument only autoranges to less sensitive audio
Increased Accuracy.
Accuracy of FM readings may be improved by using the FM Calibrator (refer to FA4 page 3-181) and by taking into account the effects of residual noise (refer
Calihration on to Residirul Noisc h‘~jl,cl.s
Automatic Squelching.
If the RF input signal drops automatically squelched (muted, turned off). In the 8902A Measuring Receiver, RF gain can be inserted into the RF signal path too level required for measurement. or low for accurate
IF
FM demodulation, the FM measurement is gain can be inserted into the IF path to raise the signal to the
Potential Inaccuracies.
AM conditions that cause the carrier signal to disappear (such will cause inaccuracies in measurement of FM, QM, or as 100°/o input frequency,
AM or
05 (FM squelched) to be displayed when these measurements are selected. or pulse modulation) they could cause Error
Considerations When Using the RMS Detector
During FM measurements if the RMS detector is selected (Blue Key, AVG), FM de-emphasis pre- display is automatically selected. Pre-display must turn on at this time due to circuit configuration of the Measuring Receiver. When pre-display is selected this way, it will not turn off automatically when another detector is selected. Turn off pre-display (after selecting another detector) by pressing the
PRE DISPLAY key (HP-IB code: PO). Measurements could be affected by this pre-display selection.
3- 180
Model 8902A Operation
FM Calibration
FUNCTIONS
CALIBRATE, SAVE CAL, Function 12 (FM Calibration), Special Function 17 (FM Calibration
Factor)
DESCRIPTION
The accuracy of the Measuring Receiver’s FM demodulator can be checked with the internal
FM calibrator. The calibration process generates a calibration factor to compensate for the FM measurement error (within the accuracy limits of the FM Calibrator). The calibration factor can then be enabled to automatically correct the measured FM error in subsequent measurements using the SAVE CAL key or Special Function 17. With the calibration factor enabled, FM measurements can be made with an accuracy typically better than 0.5Yo. The calibration factor can be enabled, disabled, or displayed at any time.
Other instruments in the HP 8901 and 8902 RF signal analyzer family can be calibrated or cross checked with the Measuring Receiver’s FM calibrator using Special Function 12.
PROCEDURE
Self-Calibration.
To determine the measurement error of the Measuring Receiver’s FM demodulation circuits, first allow at least a half-hour continuous operation before calibration, then perform the following steps:
1. Connect the CALIBRATION AM/FM OUTPUT sensor module with an internal switch such as the to the R F INPUT with a
HP 11722A) and select FM.
50R cable (or a
2. Press the CALIBRATE key. After several seconds, the FM calibration factor is displayed in
O/o and stored (but not enabled unless already enabled).
The instrument displays 100.OOo/o if no error is measured. A display of 100.17% means the demodulator in the Measuring Receiver is reading 0.17% high. As long as the CALIBRATE key light is on and the cable is connected, calibration repeats and the FM calibration factor is updated approximately every 17 seconds. key.
To turn off
FM the calibrator, select CALIBRATE or any Measurement
NOTE
For optimitm accirracy, the instritmcnt shoirld hc continiroirsly opmating for at least two FM one
Calihration Factors rtwiwd iist’dl t w n chain may
if
haw hoirr hcfore calihration is performed. the instriiment not hc.firlly is sct[lt>d. a f k r
In addition, the instrirment power-icp shoirld
.firsf not he alrcady warm, since the circirits in thc audio
Correcting Measurements with the FM Calibration Factor.
Once a calibration factor has been determined, the instrument retains that value in its non-volatile memory. This factor can be enabled to automatically correct FM measurements. The calibration factor can also be disabled or displayed.
3-181
Opera ti on Model 8902A
Selecting % CAL FACTOR (Blue Key, MHz) or 16.2 SPCL displays the Calibration Factor being used.
Enter the appropriate front-panel key or special function code
Factor as described in the following table: to manipulate the FM Calibration
~~
~~ Action:
FM Calibration
Factor
~
Disable
Enable
Display
Measurement
Mode
Any
FM
(From CALIBRATE mode)
I
I
Front-Panel Key
I
Program Code or
Special Function Code
17.0 SPCL 17.0SP
(Blue Key)
SAVE CAL sc
17.1 SPCL 17.1SP Anv
FM
%
(Blue Key)
CAL FACTOR’
CF
17.2 SPCL 17.2SP Any
3- 182
Calibrating or Cross Checking Another HP 8901 or 8902 RF Signal Analyzer.
To compute an FM calibration factor for another RF signal analyzer that has no internal calibrator, or that has an internal calibrator that is to be cross checked, use the Measuring Receiver and its calibrator as follows:
1. Connect the Measuring Receiver’s CALIBRATION AM/FM OUTPUT to the RF input of the other RF signal analyzer.
2. Key in 12.0 SPCL into the Measuring Receiver. Record the value that appears in the display.
This is the computed, calibrated, peak FM deviation (excluding noise).
3. Key in 12.1 SPCL into both instruments. Record the value that appears on the display of the
R F signal analyzer. (If display jitter makes readings difficult, key in 5.1 SPCL.) The displayed value is the weighted, peak, residual FM deviation of the calibrator’s unmodulated output as demodulated by the RF signal analyzer.
4. Key in 12.2 SPCL for both instruments. Record the value that appears on the display of the RF signal analyzer. noise).
(If display jitter makes readings difficult, select 5.1 SPCL.) is the demodulated, positive, peak FM deviation of the calibrator’s modulated output (including
5. On the RF signal analyzer, select PEAK-. Note the value displayed on the RF signal analyzer. If the difference between the results of steps 4 and 5 is three counts or less in the least significant digit, an average between the two need not be computed; use the result from step 4. If the difference between the two readings is greater than three counts in the least significant digit, compute the average as follows:
(12.2 result) =
(result of step 4)
+
(result of step 5 )
2
6. Compute the FM calibration factor of the RF signal analyzer as follows:
FM Calibration Factor (%) = 100 x
(12.2 result) - (12.1 result)
(12.0 result)
Model 8902A Operation
7. To use this FM calibration factor to correct FM measurements made with the RF signal analyzer, enter the value as a ratio reference and use the Ratio function in the RF signal analyzer.
The Special Function codes are summarized in the table below:
Function
Display computed peak FM
DisDlav demodulated Deak residual FM
~
Display demodulated peak FM
Special
Function
Code
12.0 SPCL
12.1 SPCL
12.2 SPCL
I
Program Code
12.0SP
12.1SP
12.2 SP
I
HP-IB PROGRAM CODES
HP-IB codes for enabling, disabling, or displaying the internal FM calibration factor are provided in
“Procedures”. The HP-IB codes for the FM Calibrator Special Function used to calibrate another
R F signal analyzer are also provided as part of “Procedures”.
FM = M2
CALIBRATE on = C1
CALIBRATE
SPCL = SP off = CO
INDICATIONS
Self-Calibration.
When the CALIBRATE key is pressed, approximately 17 seconds pass during which the instrument configures itself and tunes to the calibrator’s signal. The display indicates four dashes (----) and lights the Yo annunciator. Once the FM Calibration Factor has been computed,
Subsequent updates occur approximately every 17 seconds. it is displayed.
Correcting Measurements with the FM Calibration Factor (Self-Calibrated).
When the calibration factor is enabled, the FM deviation measurement is always a corrected measurement.
If
O/o
CAL FACTOR is selected, and the FM calibration factor is enabled, the FM calibration factor is displayed. If % CAL FACTOR displayed. (Note the resolution of is selected, and the FM calibration factor
IYo.) is disabled, 100% is
Calibrating Another RF Signal Analyzer.
The Measuring Receiver displays the computed FM two dashes (--) throughout the rest of the procedure. deviation ( Special Function 12.0), but shows
3- 183
Operation Model .8902A
MEASUREMENT
TECHNIQUE
When FM is selected and CALIBRATE is selected, a within the calibrator is driven to one end of its nominal tuning range. The frequency of the VCO is counted, and the oscillator is driven to the opposite end of its tuning range where it is counted again. The peak FM
10.1 MHz voltage controlled oscillator (VCO) deviation is computed from these measurements.
While the VCO is at one end of its range, the residual FM of the calibrator (very low) and the
FM Demodulator (more significant) are characterized and weighted. (Refer to Residual
Noise
EJkts
The VCO is frequency modulated by a 10 kHz modulation oscillator, and the demodulator makes another computed.)
FM
FM measurement. (Both peak detectors are used and the average is
The Measuring Receiver compares the deviation (static measurements) with the demodulated
(toggled measurements) and computes its accuracy error as follows:
FM
FM Calibration Factor (%) =
Demodulated FM
-
Demodulated Residual FM
Computed FM x 100
All segments of the calibration are carefi~lly monitored. If any segment is out of limits, the calibration is aborted and Error 08 is displayed.
10.1 MHz
VOLTAGE
OS CI L LAT q-1
0 R w-p 1-1
C L E R
BUFFER
COUNTER
CONTROLLER
CALIBRATION
OUTPUT
I
COMMENTS
Default Calibration Factor.
If t.he instrument's non-volatile memory is erased, 100.00% is used as the default calibration factor.
Updating the FM Calibration Factor.
Whenever FM calibration is performed, the instrument updates the stored FM calibration factor.
3- 184
Model 8902A Operation
Special Function Cancellation.
Performing calibration cancels most Special Functions.
When Using the FM Calibrator to Calibrate Other Signal Analyzers.
The modulation waveform of the FM Calibrator is a rounded trapezoid. An signal analyzer, which uses it as a calibration standard, must have demodulation and audio processing circuits which preserve the full fidelity of the waveform.
Automatic FM Ranging.
When used to calibrate an RF signal analyzer, Special Functions range to that of 0 to
SPCL
40 kHz (Special Function 2.2).
12.1
Upon exiting the and 12.2 set the FM deviation
FM Calibrator Special Function, the audio ranging is not returned to automatic but remains fixed (thus leaving the
Key in 2.0 to return the audio ranging to automatic.
SPCL light on).
3- 185
Model 8902A Opera tion
FM De-emphasis
FUNCTIONS
Pre-Display, 25ps, 50ps, 7 5 ~ s .
DESCRIPTION
The de-emphasis networks equalize the pre-emphasis often encoded on broadcast FM signals. This type of equalization provides a simple means of reducing audible noise on systems. Pre-emphasis gives a dB corner the pre-emphasis dB per octave, high-frequency boost or relationship between the time constant, rO, and the 3dB corner frequency, fo,
FM communication to the baseband audio before modulating the carrier. De-emphasis reverses the boost after demodulation at the receiver. The 3 is f0
=
3
5 ~ ~ .
The 3dB corner frequencies of the de-emphasis equalizers (typically accurate to f3%)are listed in the following table:
I
Time
Constant
(PSI
25
50
75
750
FM De-emphasis
3 dB
Frequency
(Ha
6366
31 83
21 22
212.2
PROCEDURE
To add de-emphasis to the demodulated FM, select the key corresponding to the desired time constant. (Unless AUDIO INPUT has been selected, the de-emphasized FM is available at the
MODULATION OUTPUT/AUDIO INPUT.) To also display the de-emphasized FM, select PRE
DISPLAY.
HP-IB
In local operation, to turn off one of the de-emphasis functions, press the lighted key a second time.
In remote operation, turn the equalizers off with code PO. (HP-IB code PO also turns off the PRE
DISPLAY function.)
3- I87
Operation Model 8902A
EXAMPLE
To measure the positive peak FM deviation of a carrier with 750 ps de-emphasis inserted before the deviation measurement:
LOCAL
(keystrokes) r
DETECTOR
I.)
DE-EMPHASIS a m
(program codes)
Measurement
Detector
De-emphasis
HP-I6 PROGRAM CODES
~
FM De-emphasis
~ Time
Constant PRE DISPLAY On PRE DISPLAY Off
(PSI
Filters off
25
50
75
750
POP1
P1 P2
P1 P3
P1 P4
P1 P5
PO
POP2
POP3
POP4
POP5
I
COMMENTS
Input/Output Status.
When selected, the de-emphasis networks are inserted in the audio signal path following the audio filters. They will affect the output signal at MODULATION OUTPUT/AUDIO INPUT and can be placed before the audio detector and display. (Refer to the block diagram in FM.) De-emphasis has no affect on the rear panel FM Output.
When Measuring Low Deviation FM
When 750 ps de-emphasis is selected, FM sensitivity at the MODULATION OUTPUT/AUDIO
INPUT is increased by a factor of ten. The range of deviation measurements is restricted to
40 kHz peak deviation or less after de-emphasis. The display resolution, however, remains the same as without de-emphasis unless the pre-display mode has been selected at which time the display resolution increases ten times. This feature provides greater resolution for measuring low deviation
FM.
3- 188
Model 8902A Operation
HP-18. Automatic Selection of Pre-Display.
When the true rms detector is selected, the pre-display mode for FM de-emphasis enabled. This is true whether FM has been selected is automatically constant, however, remains unaffected.) The pre-display mode remains enabled until deliberately disabled. This idiosyncrasy is important to or not. (Selection of the FM de-emphasis time remember when programming the instrument via HP-IB.
Considerations When Using the RMS Detector
During FM measurements if the RMS detector is selected (Blue Key, AVG), FM de-emphasis pre- display is automatically selected. Pre-display must turn the Measuring Receiver. When pre-display another detector is selected. Turn
PRE DISPLAY key (HP-IB code: off
PO). on at this time due to circuit configuration of is selected this way, it will not turn off automatically when pre-display (after selecting another detector) by pressing the
Measurements could be affected by this pre-display selection.
3- 189
Model 8902A Operation
FM Output
Do not apply greater lhan 10 Vpk (a(* conncclor
or
damagc lo thc
+ dc) into instrrrrncnt may
(he rem-pancl FM OUTPUT rtwlt.
DESCRIPTION
The rear-panel FM OUTPUT (dc-coupled, for the FM demodulated from the
10 kCl output impedance) provides an auxiliary outpiit
RF input signal. This output enables monitoring display of very low. other measurements (such as AM, QM, or audio signals) or of FM during when the modulation rate is
The output signal comprises both
(bandwidth 16 a dc voltage, related kHz, one pole) proportional to to the counted IF frequency, and an ac voltage the FM deviation.
With the input signal centered in the IF, the nominal dc offset voltage at FM OUTPUT is approximately 0.8 Vdc for the 1.5 MHz IF and -5.6 Vdc for the 455 kHz typically 6 V/MHz or 6
IF. The FM sensitivity is mV/kHz. The d c voltage at FM OUTPUT can be calculated as follows:
V d c = V,JJ -
(FREQ ERROR)
1000 where:Vdc=representation of the dc voltage at FM OUTPUT volts,
V,,J=representation of the dc offset voltage for the
K=the FM sensitivity in mV/kHz, or V/MHz, and
FREQ ERROR=the kHz error
IF used volts, displayed when FREQ ERROR is selected.
Measure V,,ff when the frequency error is using the following procedure:
0 kHz. The sensitivity can be measured
PROCEDURE
To determine the sensitivity of the FM OUTPUT, apply an unmodulated 2 MHz carrier at the R F
INPUT. (Select 3.2 SPCL, which uses the 1.5
Measure the dc voltage at the output with note the dc voltage, The FM sensitivity (K
MHz IF described in Filters, R F in V/MHz or mV/kHz) is:
and IF
a dc voltmeter. Move the carrier to 1 MHz and again
K
= (Vdc
*
2 MHz)
-
(Vdc f 1 M H z )
EXAMPLE
A 2 MHz unmodulated signal is applied
FM sensitivity is: to the RF INPUT. A dc voltmeter connected to FM
OUTPUT measures +3.89 Vdc. When the carrier is set to I MHz, -2.272 Vdc is measured. The
(3.890)
-
(-2.272) = 6.162 V/MHZ
OT
6.162 mV/kHz
3-191
Operation
BLOCK DIAGRAM
Model 8902A
IF
ON
’
I
~
FM
O ~ i f p i i f
COMMENTS
Inherent IF Component.
FM OUTPUT which is unsquelched and also contains is greatest when operating at a a significant component at twice the carrier frequency of 150 kHz.
IF frequency
Inverted AC Output Component.
Note that the sense of the ac output component (corresponding to the demodulated for carriers above 2.5 MHz.
FM) is inverted
Accuracy of Output During RF Level Measurements.
When
FM
RF Level rneasiirements (Special Function
OUTPUT
35) are made, automatic selection of RF input attenuation and gain overrides any manual settings that might have been selected with Special
Function 1. The selected attenuation could degrade the accuracy of measurements made on the signal.
3- 192
Model 8902A Operation
lone-Burst Receiver
FUNCTIONS
Special Function 18 (Tone-Burst Receiver)
DESCR
I
PTlON
In some FM applications (mobile radio testing, &ar example), after a transmitter is keyed, it issues squelch tones for a brief interval. Often, it is necessary to measure the frequency of the squelch tones. This measurement is made difficult by the noise in the demodulated audio during the short delay between the keying of the transmitter and the appearance of the audio tones.
Special Function 18 enables the Measuring Receiver to be configured as a tone-burst receiver. This function inserts a user-selectable delay between the instant the instrument senses an
RF INPUT and the time when it turns on
RF its
When an external counter is connected to this output, the squelch tone will reach the counter only when a valid measurement can be made. The time delay is selectable from 1 through 99 milliseconds.
The following photo illustrates a 99 ms delay between transmitter keying (lower trace).
+0.5V
Oscilloscope Photo Dipicting a 99 m.5 Delay &tween Transmitier Keying Pirlse
(Lowcr
Tract,)
clivafion qfMOD(JI,A TION OUTPUT/A UDIO INPUT
3-193
Operation Model 8902A
PROCEDURE
In order to successfully measure tone bursts, tune and range the Measuring Receiver:
1. Select FM.
2. Select an audio detector and if desired, audio filters and FM de-emphasis.
3. Key on the transmitter and allow the Measuring Receiver to range and tune automatically.
4. Select RANGE HOLD to hold all ranges and tuning.
5. Select the time delay to be inserted between the moment the transmitter is keyed and the time
MODULATION OUTPUT/AUDIO INPUT is to be turned on. This delay becomes the Special
Function suffix. (If 18.0 SPCL is selected, the Measuring Receiver executes a 99 ms delay.)
6. Enter the Special Function code 18.” (where NN is the selected delay in milliseconds), then select SPCL. (If 18.5 is entered, a 5 ms delay is executed. For a 50 ms delay, enter 18.50.)
The Measuring Receiver is now initiated to receive tone bursts. To exit this mode, select any key except the Blue Key, S (shift), or LOCAL Key, or numeric keys.
PROGRAM
CODES
The Special Function code suffix is derived from the time delay as described in “PROCEDURE”.
SPCL
= SP
INDICATIONS
As the numeric code is entered, it appears on the front panel display. When the SPCL key is pressed,
18.” is displayed (NN is the delay in milliseconds). If no RF is at the RF dashes f--) are displayed.
INPUT connector, two
COMMENTS
Suggested Use of Maximum Delay.
When using the Tone Burst Receiver Special Function, use the delays require very careful setup since, with no input, the high-gain IF Amplifier and Limiters “tune” the noise to an average frequency the instrument, the IF shifts abruptly to the nominal frequency. transmitter is on is close to, often
99 slightly different than the nominal
This for
IF. best results. Shorter
When RF first enters shift creates an FM transient which settles out after a short period and thus is not apparent with longer delays. With short delays the transients can be avoided by carefully tuning the instrument or ms delay so that the IF frequency when the equal to the average IF frequency when the transmitter is off.
HP-IB.
This function is best used when operating via HP-IB since the ext.ernal counter connected to the output of MODULATION OUTPUT/AUDIO INPUT may need to acquire several sets rapid succession (when counting multiple tones, for example). of data in
Selective Range Holding.
Ranges can be held for this function using the individual Special Functions for each parameter instead of using the Range Hold key.
Default Condition.
Special Function code 18.0 provides a 99 ms delay.
3- 194
Model 8902A
Operation
Tone Burst Frequency Cannot Be Measured.
The audio frequency measurement mode cannot be used to measure the frequency of the tone burst.
@M But Not AM.
This feature works also with the QM measurement mode but not AM.
3- 195
Model 8902A Operation
FUNCTIONS
cPM, Special Function 2 (Audio Range)
DESCRIPTION
The @M key enables the Measuring Receiver signal. The demodulated to measure the phase deviation of the tuned input
OM is present at MODULATION OUTPUT/AUDlO INPUT.
The OM measurement is specified only for RF carriers measurements can be performed from 10 to 1300 MHz; however, @M on carriers from 150 kHz to 10 MHz.
The OM measurement is only specified low frequency 3 dB limit is typically 7 Hz. modulation rates from 200 Hz to 20 kHz; however, the
The following figure shows the display resolution for different combinations of peak phase deviation and modulation rate.
400
0.1 RADIAN
RESOLUTION
40
0.01 RADIAN
R ESO LUTl ON
4
0.001 RADIAN
ESO LUT ION
L
I I I I I I
200 Hz 500 Hz 1 kHz 2 kHz 5 kHz 10 kHz 20 kHz
MODULATION RATE
PROCEDURE
To make a OM measiirement, first tune the instrument to the input signal by selecting AUTOMATIC
OPERATION. Select OM.
Select an audio detector: PEAK+. PEAK-, PEAK by pressing the Blue Key and the RMS used for audio distortion measurements.) is
3t /2. AVG, less accurate or in
RMS. (The RMS detector, selected measuring cPM and is typically only
3-197
Operation Model 8902A
The following table lists the different measurement range limits that can be selected with Special
Function 2:
Modulation Special
Function
Code
Automatic Selection
10.4 RMS
14
14
Pk, Avg
Pk, Avg, RMS
540
2.0 SPCL
2.4 SPCL
2.4 SPCL
2.1 SPCL
Pk, Avg, RMS 2.2 SPCL
1400 Pk, Avg, RMS 2.3 SPCL
Program Code
2.0SP
2.4SP
2.4SP
2.1SP
2.2SP
2.3SP
Display
Resolution
(radians)
MODULATION
OUTPUT
Sensitivity
(mvaclradian)
Automatic Selection
0.0001
0.001
0.001
10
1
1
0.01
0.1
0.1
0.01
To filter the demodulated signal, select the appropriate filter keys. (Refer to
Airdio Fi1rer.Y
EXAMPLE
To measure the positive-peak phase deviation of a signal in a 50 Hz to 15 kHz post-detection bandwidth:
LOCAL
(keystrokes) r
’I
El m a
(program codes)
Measurement
L T L
Detector
Filters
HP-IB PROGRAM
All HP-IB
QM M3
CODE cPM measurements are provided in “Procedures”.
3- 198
Model 8902A Operation
MEASUREMENT TECHNIQUE
The QM on the IF is first demodulated by a frequency discriminator. The amplitude of the discriminator’s output is proportional to the frequency deviation. The demodulated signal is filtered and passed through an integrator, which extracts the phase information. The integrator’s output is detected and displayed as phase deviation in radians. The integrator’s output is made available at the
MODULATION OUTPUT/AUDIO INPUT.
@M Mi>autrcmcnf Block Diagram
COMMENTS
Frequency and Distortion Measurements.
The demodulated signal’s frequency and distortion can also be measured. (Refer to A iici‘io MuasirrtJ-
ments
Relative Measurements.
If iPM deviation is to be displayed relative to a reference, enter the value as a ratio reference using the RATIO key. (Refer to Rafiu
Peak Detector. The PEAK+ detector always detects the upward carrier phase excursion while the PEAK- detector always detects the downward carrier phase excursion. The PEAKf/2 detector sums the upward and downward phase-excursion readings and divides the total by two an average value.) of the two peak values. (Do to provide
Inverted Output Signals.
When operating with carrier frequencies below 2.5 MHz, the output signal at MODULATION
OUTPUT/AUDIO INPUT is inverted unless the 455 kHz IF is selected. When operating with carrier frequencies above 2.5 MHz or when using the that of the >20 kHz LP FILTER.
455 kHz IF, the upper limit of the modulation rate is
3- 199
Operation Model 8902A
Automatic Range Selection.
The routine which automatically selects the modulation range contains regions of overlap between the following displayed peak deviations:
0.35 and .4 radians, 3.5 and 4 radians, and 35 and 40 radians.
When using the average or RMS detector, ranging will occur at readings lower than these. In general, if the modulation is reduced from a higher range into an overlap region, the range does not change.
To range the display for increased resolution, press the QM key a second time. To set the instrument to a selected modulation range, refer to Airdiio Range
1.
Potential Inaccuracies.
AM depths approaching 100Yo cause the carrier to nearly disappear and may cause inaccurate measurement of QM deviation or Error 05 (FM squelched).
Input/Output Status.
When QM not QiM. is selected, the signal at the rear-panel FM OUTPUT still represents demodulated FM,
Increased Accuracy.
Accuracy of
(Refer to cPM readings may be improved by taking into account the effects of residual noise.
Re.$idi/al
l$2cts
19.)
Phase Deviation in Degrees.
To display phase deviation in degrees instead of radians, enter 1.745 as a ratio reference and select
RATIO. (Refer to Rulio
Pulsed Phase Modulation.
Pulsed phase modulation, such as phase by the Measuring Receiver. shift keying, cannot be accurately demodulated or measured
Recommended Filter Selection.
Because of the high sensitivity of the OM measurement to low-frequency audio (microphonics, hum, etc.), use automatically.) of the 50 Hz or 300 Hz low-pass filter is recommended. (Neither is switched in
3-200
Model 8902A Operation
Audio Detectors
FUNCTIONS
PEAK+, PEAK-, PEAJGt/2, PEAK HOLD, AVG, RMS.
DESCRIPTION
The Measuring Receiver provides three types of audio detectors: peak responding, average respond- ing (rms calibrated), and true rms. These three detectors provide six modes of audio measurements:
.Positive Peak (PEAK+)
*Negative Peak (PEAK-)
.Average of Positive and Negative Peaks (PEAK+/2 mode)
.Positive or Negative Peak Hold (PEAK HOLD)
.Average (AVG:RMS Calibrated)
0
True RMS (RMS)
The two peak detector keys. when pressed individually, select whether the positive peak or the negative peak of the demodulated signal is measured. When the two peak detector keys are pressed simultaneously (the PEAK&/2 mode), the positive and negative peaks are averaged according to the following equation:
Peak Average =
(Peak+)
+
(Peak-)
2
Peak Hold detection is used in conjunction with positive or negative audio peak detector modes. This mode enables the instrument to hold and display indefinitely, the largest peak detected. This feature is usefiil for capturing the peak maximum of a modulation transient.
Average detection selects an average-responding detector that is calibrated value of a sinewave. to read the rms
True RMS detection selects a true rms detector to measure audio signals. Also, noise and residual measurements are best measured with the true rms detector. This detector is automatically selected and is the only one used with the external audio voltage measurement
(Special Function
Function 29).
30). to “COMMENTS”.) audio distortion measurement and the SINAD measurement (Special
Selection of this detector also affects the FM pre-display de-emphasis. (Refer
Once selected, a detector remains unchanged and is automatically activated each time modulation measurements are made until another detector selected, the true rms detector remains active.) is selected (except for the true rrns detector as discussed in the previous paragraph). (However, once it is automatically
3-20 1
Operation Model 8902A
PROCEDURE
When a modulation measurement is selected, a detector is automatically activated.
To obtain a peak detector, select either PEAK+ or PEAK-. Press both keys simultaneously to enable the peak-average (PEAK;t/2) mode.
Peak hold is used only with the peak detectors. Selecting PEAK HOLD initiates the peak hold mode.
To initiate another peak hold, press that key again. The display is now updated with the new peak.
The peak hold feature does not operate in the peak-average mode.
To obtain the average-responding, rms-calibrated detector, select AVG.
To initiate the true rms measurement, select RMS automatically for the external audio level measurement (Special Function measurement, and SINAD measurement (Special Function 29).
30), audio distortion
HP-IB PROGRAM CODES
Function
PEAK+
PEAK-
PEAK HOLD
AVG
RMS
PEAKd2
I -
Code
D1
D2
D3
D4
D8
D9
COMMENTS
Input/Output Status.
The signal at MODULATION OUTPUT/AUDIO INPUT, AM OUTPUT, or affected by the DETECTOR keys.
FM OUTPUT is not
True RMS Detector.
Only the true rms detector can be used for external audio level (Special Function distortion measurement, and SINAD (Special Function 29.)
30) and for audio
HP-IB Automatic Selection of Pre-Display.
When the true rms detector is selected, the pre-display mode enabled. This is true whether FM has been selected or for FM de-emphasis not. (Selection
of
the FM is automatically de-emphasis time constant, however, remains unaffected.) The pre-display mode remains enabled until deliberately disabled. This idiosyncrasy is important to remember when programming the instrument via HP-IB.
Peak Detector’s Response Time.
A slower response time
(Refer to A iidio for the audio peak detectors can be selected with Special Function 5.1.
3-202
Model 8902A Operation
Peak Hold
Mode.
When the peak hold mode is selected, the limited rise time of the peak detector circuitry can cause a slight measurement error for narrow, one-time modulation transients. To prevent this error, repeat the peak-generating process several times while leaving the peak hold mode active.
If PEAK HOLD is selected while the average or true rms detector mode is active, the detector will switch to the peak detector mode previously selected. if PEAK HOLD peak-average (PEAKf/2) mode is active, the detector reverts to PEAK+ with PEAK HOLD.
HP-I6
In remote operation, new peak-hold cycles can only be initiated by code D3. Thus, if the instrument is in HP-IB Hold mode (code TI), issue code D3 to initiate a peak-hold cycle. Although the display cannot be updated when in HP-IB
HP-IB hold via the triggering codes
Hold, the peak is captured, stored and updated. Upon leaving
(T2 since the peak-hold cycle was initiated. or T3), the data output represents the greatest peak captured
3-203
Model 8902A Operation
Audio
Detector Response
FUNCTIONS
Special Function 5 (Audio Detector Response)
DESCRIPTION
When making modulation measurements, both the udio p ments including SINAD)' ak detector response (for peak measure- and the digital averaging response (for rms measurements) are usually fast.
A slower response time (narrower detection bandwidth) can be enabled using Special Function 5.1.
The slow response time improves measurement readability on unstable or noisy signals whenever display jitter is excessive.
PROCEDURE
The Measuring Receiver is normally set for fast response. enter the corresponding Special Function code, then select SPCL. to slow or vice versa,
Audio Detector
Response
Fast
Slow
Special
Function Code
5.1 SPCL
Program
Code
5.0SP
5.1 SP
COMMENTS
Default Condition
When the instrument is first turned on or when Automatic Operation or Instrument Preset is selected, the response time returns to fast.
The slow rcsponsc timc for SINAD is not availablc with Grmwarc datc codcs 234.1985 and bclow. (To display thc firmwarc date codc. sclcct 42.0 SPCL.) To ordcr a ROM scl that contains this spccicil function. contact thc ncarcst HP salcs office.
3-205
Model 8902A Operation
Audio Filters
FUNCTIONS
HP FILTER, LP FILTER
DESCRIPTION
High-pass and low-pass filters can be inserted in the path of the demodulated signal.
The filters are used for such tasks as rejecting interfering audio signals such as line hum and sub-carriers. They also provide pre-defined bandwidths for residual noise measurements.
PROCEDURE
Insert the desired demodulated signal filter by selecting the appropriate keys. Only one high-pass and one low-pass filter can be inserted at once.
To remove a filter, select the key again.
To select a different filter, press the key corresponding to the desired filter.
HP-IB codes for the various filter keys (listed in the following table) only insert the filters. To remove a high-pass or low-pass filter via HP-IB, use code HO or LO (respectively), or select another filter.
HP-IB
PROGRAM CODES
HP FILTER
ALL OFF
50 Hz
300 Hz
Program Code
HO
H1
H2
LP FILTER
ALL OFF
3 kHz
15 kHz
>20 kHz
Program Code
LO
L1
L2
L3
3-207
Operation
BLOCK DIAGRAM
~
Model 8902A
MODULATION OUTPUT/
AUDIO INPUT
3-208
A itdio FiI1sr.s Block Diagram
COMMENTS
Filter Selection Affects Modulation Output.
The selected filters are always in the path of the demodulated signal independent of the selection of a modulation measurement. Thus, unless turned off, the output of MODULATION OUTPUT/AUDIO
INPUT is filtered. In addition, the selected filters remain in modulation measurements. effect when switching between
Automatic Filter Selection.
Under certain conditions, filters are inserted automatically. When the 455 the RF input is less than 2.5 MHz, filter has been selected. (The ALL low-pass filter selected when operating with the
MHz IF is selected. the
OFF
15
>200 kHz
455 kHz IF is inserted low-pass filtering cannot kHz
inl less another low-pass be
IF is automatically turned is used, or when selected.) The off
15 kHz when the 1.5
Bandwidth Limitations.
With no filters selected, the post-demodulation bandwidth is from less than
200 kHz.
20 Hz to greater than
(These frequencies refer to the limits over which measurement accuracy is specified, not the 3 dB bandwidth.) However. the IF circuits and demodulators impose more severe bandwidth
Model 8902A Operation
1imit.s. Refer limitations. to each specific measurement in these Detailed Operating Instructions for bandwidth
Filter Characteristics.
The individual filter characteristics are given below. The designation and is typically accurate to *3%.
3 dB bandwidth is specified in the filter’s
High-Pass Filters:
50 Hz High Pass: Two-pole Butterworth, 1% flat to 4 0 0 Hz
300 Hz High Pass: Two-pole Butterworth, 1% flat to <1 kHz
Low-Pass Filters:
3 kHz Low Pass: Five-pole Butterworth, 1% flat to >1 kHz
15 kHz Low Pass: Five-pole Chebyshev, 1% flat to >10 kHz
>20 kHz modulation, this filter typically overshoots <I%. This filter’s 3 dB point is typically kHz.)
Low Pass: Nine-pole Bessel, 1% flat to >10 kHz. (When used with square wave
I10
Filter Selection Does Not Affect Some Measurements.
External Audio level, distortion, and SlNAD measurements are unaffected by the audio filters.
Recommended Filter Selection.
Because of the high sensitivity hum, etc.), use of the automatically.)
50 Hz of the @M measurement to low-frequency audio (microphonics, or 300 Hz low-pass filter is recommended. (Neither is switched in
3-209
Operation Model 8902A
Audio Range
FUNCTIONS
Special Function 2 (Audio Range)
DESCRIPTION
The Measuring Receiver is usually set to automat.;ally select the audio range appropriate desired measurement. To set the audio range manually, use Special Function 2. for the
PROCEDURE
To set the audio range
Function code. or to re-enter the automatic selection mode, select the corresponding Special
Detector
S e I e c t e d
Special Modulation
Range
Peak2
(O/o)
I
Automatic Selection
1
Pk, Avg, RMS
2.0 SPCL +
Pk, Avg, RMS or
2.3 SPCL
2.0SP
2.4SP
2.4SP
2.1 SP
2.2SP or
2.3SP e
Display
Resolution
(O/O)
Automatic Selection
0.001
0.01
0.01
0.1
MODULATION
OUTPUT
Sensitivity
(Vac/O/o AM)
0.1
0.1
0.1
0.01
3-2 1 I
Opera tion Model 8902A
A irdio Rangc A vailahk jor FM
Modulation
Range
(PeakkkHz dev.)
Detector
Selected
Special
Function
Code
I
Automatic Selection
L
Pk, Avg, RMS
Pk, Avg, RMS
I I
I
2.0 SPCL
2.4 SPCL’
2.4 SPCL
2.4 SPCL’
2.1 SPCL’
2.4 SPCL
2.1 SPCL
2.2 SPCL’
I
5400 Pk, Avg, RMS 2.3 SPCL
With 750 ps de-emphasis, pre-display only.
2.0SP
2.4SP
2.4SP
2.4SP
2.1 SP
2.4SP
2.1SP
2.2SP
2.2SP
2.3SP
2.3SP
I
1
10
100
(Hz)
OUTPUT
Sensitivity
(Vac/Oh
Automatic Selection
Hz)
0.01 100
0.1 10
1
I
0.1
0.01
A rrdio Rang(> vailahlt>jor @A4
Modulation
Range
(Peakkrad. dev.)
Detector
Selected
Automatic Selection
10.4
I
RMS
1 4 Pk, Avg
1 4 Pk, Avg, RMS
Special
Function
Code
2.0 SPCL
2.4 SPCL
2.4 SPCL
2.1 SPCL
Program Code
2.0SP
2.4SP
2.4SP
2.1 SP
140 Pk, Avg, RMS 2.2 SPCL 2.2SP
I
1400
I
Pk,AvaRMS
I
2.3SPCL
I
2.3SP
Display
Resolution
(radians)
MODULATION
OUTPUT
Sensitivity
(mvaclradian)
Automatic Selection
0.0001
I
10
0.001 1
0.001 1
0.01
0.1
0.1
I
0.01
3-2 12
Model 8902A Operation
COMMENTS
Audio Range Effect on Distortion Measurements
The selected Audio Range has no effect on audio distortion or SINAD measurements.
When the audio range selected is too high for the level tracks the displayed values.) When the audio range generated. (The output of the MODULATION OUTPUT/AUDIO INPUT will probably be clipped.)
Depending nominal values listed in the tables above. is too the audio signal, the signal-to-noise ratio will be low (no error is generated). (The output of MODULATION OUTPUT/AUDIO INPUT on of low for the audio signal level, Error the audio filtering and detector in use, Error
04 is
04 may not be generated at exactly the
Disabling Error 04 Inhibits Audio Autoranging
When Error 04 is disabled (refer
Receiver automatically ranges to to Error Message Disahk Conlrol
the Measuring a less sensitive range when the signal level requires, but it does not range back when the audio level is reduced. This feature is used most often when modulation varies widely with time (such as off-the-air demodulation of a broadcast signal).
3-2 I3
Model 8902A Operation
Modulation Output/Audio Input
FUNCTIONS
AUDIO INPUT
Do not apply greater than I O Vdc or greater than +30 dBm ( I watt) into
MODULATION OUTPUT/A may result.
UDIO
INPUT or damage to the instriimenl
NOTE
For
optimrrm
signal flatness,
cables
attached io MODUI.. TION
A UDIO INPUT (when used as an oulpirr) should bc terminatt*d in 600i2
.
DESCRIPTION
Modulation Output.
MODULATION OUTPUT/AUDIO INPUT provides a calibrated output for signals demodulated by the Measuring Receiver. The output signal available at the connector usually corresponds to the current modulation measurement. (The output is dc coupIed and has a a BNC female connector.)
600C.l
Audio Input.
The input at MODULATION OUTPUT/AUDIO INPUT also provides external access to the audio measurement circuits. The input impedance at the connector is 100 kn.
3-2 15
Opera tion Model 8902A
Effects on Modulation Output/Audio Input During Measurements.
Measurements have a direct effect on table lists the functioning of
MODULATION OUTPUT/AUDIO INPUT.
MODULATION OUTPUT/AUDIO INPUT for each
The following measurement.
I AM
AUDIO DISTN
AUDIO FREQ
Measurement
AUTOMATIC OPERATION
FM
FREQ
INSTR PRESET
30.0 SPCL (Ext. Audio RMS Level)
33.0 SPCL (LO Frequency)
34.0 SPCL (IF Frequency)
35.0 SPCL (RF Level)
36.0 SPCL (Peak Tuned RF Level)
Measuring Receiver's Response
Selects the demodulated AM signal (unless AUDIO INPUT is selected).
Measures signal available at MODULATION OUTPUT/AUDIO INPUT (depends on
AUDIO INPUT key selection).
Measures signal available at MODULATION OUTPUT/AUDIO INPUT (depends on
AUDIO INPUT key selection).
Selects the last-selected modulation measurement.
Selects the demodulated FM signal (unless AUDIO INPUT is selected).
Selects the last-selected modulation measurement.
Selects the last-selected modulation measurement.
Refer to Instrument Preset
Selects the demodulated FM signal (unless AUDIO INPUT is selected).
~~~
Blanks output; turns off all Modulation Output, Audio Input keylights.
_ _
~~
~
Blanks output; turns off all Modulation Output, Audio Input keylights.
Selects the last-selected modulation measurement.
Selects AUDIO INPUT.
Selects the last-selected modulation measurement.
Selects the last-selected modulation measurement.
Blanks output; turns off all Modulation Output, Audio Input keylights.
Blanks output; turns off all Modulation Output, Audio Input keylights.
I
3-2 16
Model 8902A Operation
Display Resolution vs. Modulation Output Sensitivity
In Automatic Operation, when the Modulation Output/Audio Input feature is used, the output autoranges. Autoranging usually occurs between 3.5 and 4 Vpk, open circuit. Many variables, however, affect the autorange limits and hence the displayed measurement resolution. The variables include: type of modulation, audio detector, audio filtering, and FM de-emphasis. Special Function
2 permits manual setting of the audio range.
The following table examines this relationship. (Refer to Airdio Rangc o n page 3-211 for more information on modulation ranges.)
Display
Resolution
(O/O)
AM
Modulation output
Sensitivity
(Va C/~/O)
0.001 0.1
0.01 0.1
Display
Resolution
(Hz)
0.01
0.1
1
10
FM
Modulation output
Sensitivity
(mVac/Hz)
10
1
0.1
Display
Resolution
(radians)
4M
Modulation output
Sensitivity
(mvaclradian)
0.001
0.01
1
0.1
'Available only with 750 ps de-emphasis, pre-display.
BLOCK DIAGRAM
Modirlution
Oiilprit/A
itdio Inpiit Block Diugrum
DETECTORS r-,
,:,'_I
,:,,>
VOLTMETER
AND DISPLAY
', ,?,:,c#,-,-!,>
0
3-2 17
Operation Model 8902A
Functions That Override Audio Input.
The Audio Input function is overridden by all measurements except audio frequency, distortion,
SINAD, and external level.
Errors Disable Output Signal.
Errors 01 through 03, 05, 10, and HP-IB 96 (corresponds to a display the signal at MODULATION OUTPUT/AUDIO INPUT. of two dashes) turn off
Default Condition.
When the Measuring Receiver is first powered up, the demodulated output signal at MODULATION
OUTPUT/AUDIO INPUT is FM. The sensitivity is 0.01 mV/Hz (the least-sensitive range) and will not autorange to more sensitive ranges. This is because at power up,
04 (audio circuits overdriven) is automatically disabled. When Error to less-sensitive audio ranges is allowed.
FREQ
Safeguarding Output Signal.
When Errors 01 through 04 are always enabled via Special Function 8.8, the output signal at
MODULATION OUTPUT/AUDIO INPUT is entirely safeguarded. Under this condition the instrument operates as a calibrated receiver and an error is displayed whenever the signal at
MODULATION OUTPUT/AUDIO INPUT is uncnlibrated. (Refer to Error Mmage Disahk Confrol
Filters Affect Output Signal.
The audio high-pass and low-pass filters and FM de-emphasis affect the output but not the input of the MODULATION OUTPUT/AUDIO INPUT.
3-2 18
Model 890214 Operation
Residual Noise Effects
DESCRIPTION
To make the most accurate peak-modulation measurements, of it is necessary to measure and correct residual noise, that is, noise not on the baseband signal, but modulating the R F carrier,
The following procedure describes the measurement technique.
PROCEDURE
The following procedure enables the user to correct for the effects of residual noise on peak- modulation measurements.
NOTE
This procediire applics to sinewavc modirla!ion only.
1. Set up and make a normal peak-modulation measurement. The displayed measurement result will include the signal plus its noise, (S
+
N)#,k.
2. Press the Range Hold key to prevent autoranging. If filtering and/or de-emphasis was used in step 1, make all the following measurements with the same settings.
3. Remove the modulation from the signal and measure the remaining peak-residual noise,
Npkr on the carrier.
4. Select AVG. Measure the average residual noise,
Nau.
5. Compute
6. Use the following nomograph to determine the percent,
Npk, to
+
N ) $ , k .
N%,
be subtracted from the original, peak-signal-plus-noise measurement, (S
7. Compute the corrected, peak modulation where
N%
is expressed as a ratio (rather than in Yo).
3-219
Model 890214
Operation
3-220
EXAMPLE
An R F signal is applied to the Measuring Receiver. The modulation rate is modulation is to be measured in a IS kHz post-detection bandwidth. depth and correct for the effects of residual noise on the modulation:
To
1 kHz and the peak measure the peak AM o n
= I . \
Measurement
AU T L2
Detector
Filter
(program codes)
For the purposes of subsequent calculations, assume the displayed AM is 3O.8O0/o.
Operation Model 8902A
2. Disable auto-ranging by pressing the RANGE
LOCAL
(keystrokes)
(program codes)
R A N F HOLD El t
Range Hold
LOCAL
(keystrokes)
(program codes)
Detector
For the purposes of subsequent calculations, assume the displayed average residual AM is O.O2O/o.
5. Compute:
-
= 3.5%
6. Compute:
7. Use the nomograph
Compute: to find NO%. (For the purposes of these calculations, assume N%I is 26%.)
NOTE
This correction jizdor oJ’
<O.
1 % ofthe peak rcwding is typical q f a modidation mtmiircvnsnl of’ a yiiality modiilulion soiirct’ mcasiircd wilh thr 15 kHz low-pas.s..filter.
3-22 1
Operation Model 8902A
THEORY
Residual noise is the short-term amplitude or phase (and thus frequency) instability inherent in any CW signal source. In a measurement system composed of a signal source and the Measuring
Receiver, residual noise is contributed by both instruments. When modulation is measured with the
Measuring Receiver, both the intended and residual combined are measured. the modulation index due to
To precisely determine the baseband signal alone, the effects of residual noise must be factored out of the measurement results.
Two noise components are commonly encountered in modulation measurements: periodic (often line-related) and gaussian (random). Periodic noise and the baseband signal behave identically. The
Measuring Receiver measures the arithmetic sum of the peak or average levels of the two signals
(according to the detector selected). alone, switch the modulation noise spectrum so
To of effects domain, noise of this kind appears as random amplitude spikes (or fuzz) riding on top of the recovered off, baseband signal. The amplitude of determine the modulation index due to the baseband signal measure the peak-residual noise on the same range as before, and subtract the result from the original displayed modulation. The of random noise on the measurement system are not as straight forward. True random noise, when viewed in the frequency domain, is a continuous spectrum of frequencies at various amplitudes. The frequency of the noise spectrum is limited only by the bandwidths these spikes the observing and/or generating devices. In the time is limited by the slow rate of the measuring and/or generating devices. Peak detecting these spikes exaggerates the amount of energy present in the noise measurements are typically made with average-responding detectors and with limited bandwidths.
The measurement problem arises because modulation index is typically expressed as a peak level.
To account for residual noise in these peak measurements, the actual effects of the noise on the
Measuring Receiver’s peak detector must be determined.
A simplified diagram of the Measuring Receiver’s peak detector is shown in the following figure.
Whenever the signal-plus-noise voltage into the comparator exceeds the voltage stored on the output capacitor, C, through resistor R. When the voltage across the capacitor exceeds the voltage of the incoming signal, the comparator opens the switch again. This process continues until the voltage on the capacitor is transferred the comparator closes switch S1. The capacitor is then charged via the path from +V to the voltmeter through the sample-and-hold switch,
When very narrow noise spikes are imposed on the comparator’s input, the charging circuit’s time constant will not allow the capacitor to
S2. C is then discharged by fully charge before the noise peak has passed.
53.
RC
C 0 M PA R AT 0
+v
To Voltmetel
3-222
Model 8902A Operation
When noise alone is imposed o n the detector, it is very probable that as C begins to charge, a noise spike will exceed the voltage across the peak detector capacitor. However, as the voltage across the capacitor more nearly approaches the peak-noise level, this probability decreases. Thus the peak detector, over a significantly long time, can faithfully measure fairly high peak-noise levels.
When noise is riding on a sinewave, only the signal-plus-noise peaks exceeding the sinusoid’s peak level can add charge to the peak detector capacitor. Statistically, there is less chance that the composite input signal will exceed the voltage across the capacitor (already charged to the peak of the sinewave) when measuring a sinewave than when measuring only noise. Thus, the contribution of noise on the measured peak-modulation level decreases as the signal-to-noise ratio increases.2 simply measure the peak-residual noise present when the modulation is removed and subtract the result directly from the peak reading of the combined input, over-compensates the effects noise. of
To the
The effects of residual noise on the peak detector depend on the signal-to-noise ratio, the statistics of the noise spikes, and the response time of the specific peak detector. These effects are quantified by taking the ratio of the peak noise reading to the average noise reading. The average noise level is a truer measure of the actual amount of noise energy present, while the peak reading characterizes the peak detector and the statistics of the noise spikes.
COMMENTS
Noise Must Be Gaussian.
The primary restriction placed on this method must be gaussian (that of accounting for residual noise is that the noise repeating peaks and thus does not fall within the statistical model used to derive the nomograph given in the procedure.
A noise-peak-to-noise-average ratio component in the residual noise.
(N,k/N,,) greater than 4.4 is a strong indication of a periodic
Use Range Hold During Measurement.
Both the modulation and the noise measurements used with the nomograph should be made on the same modulation range and with the same peak-detector time-constant. Use the Range Hold key while the instrument is measuring the modulated carrier, then measure the residual noise.
Select the Highest of Successive Readings.
When characterizing the effects of residual noise on peak QM measurements using the low-pass filter, readings may jump considerably. Use the highest of 10 successive readings for all peak measurements in the computations. (Simply select PEAK seconds.)
HOLD
3 kHz and note the reading after 2
No Residual Noise in Calibration.
The residual noise‘contributions of the AM and FM calibrators and the Measuring Receiver are accounted for in the calibration procedures. It is not necessary to factor residual noise corrections into the calibration procedures described in this manual. (Refer to AM Calibration and FM
Calibration.)
Considerations When Using the RMS Detector
During FM measurements if the RMS display is automatically selected. Pre-display must turn on at this time due to circuit configuration of the Measuring Receiver. When pre-display is selected this way, it will not turn another detector is selected. Turn off off automatically when pre-display (after selecting another detector) by pressing the
PRE DISPLAY key (HP-IB code: PO). Measurements could be affected by this pre-display selection.
Rice. S.O., “Statistical Properties of a Sinc Wave Plus Random Noisc”. Bcll Systcm Tcchnical Journal. 27. No.1. (January.
1948), pp. 109-157.
3-223
Model 8902A Operation
Audio Measurements Contents
AUDIO MEASUREMENTS
Audio Frequency..
0
0
0
0
SINAD..
0 demodulated or an external audio input.
How to measure the level of external audio input.
How to
How to
...................................................................................... count the demodulated audio frequency. count an external audio frequency.
Audio Distortion and Level..
How to measure audio distortion (only at 400 or 1 kHz) on either an internally
................................................................................................. measure SINAD an external audio input.
(only at 400 or 1 kHz) on either an internally demodulated or
.3-227
.3-229
.3-233
3-225
Model 8902A Operation
Audio
Frequency
FUNCTIONS
AUDIO FREQ, AUDIO INPUT
DESCRIPTION
Audio Frequency counting can be performed on either demodulated internal signals or external audio signals as determined by the AUDIO lNPUT key.
PROCEDURE
To count the frequency of the audio signal demodulated from the select AUDIO FREQ
R F signal at the INPUT connector,
To count the frequency of an external audio signal at the MODULATION OUTPUT/AUDIO
INPUT connector, follow the above procedure, and then select AUDIO INPUT. The measurement range is 20 Hz to 250 kHz. The input signal should not exceed 4 Vrms. The input impedance is approximately 100 kn.
HP-IB PROGRAM CODES
AUDIO FREQ =
AUDIO INPUT
SI
= AI
MEASUREMENT TECHNIQUE
The audio frequency is measured by a reciprocal-type counter. The input can be either the demodulated RF or an external audio input at the MODULATION OUTPUT/AUDIO
10 MHz time base reference with the audio input signal for at least 100 ms. The frequency is then determined by the following equation: audio frequency =
(number of cycles of audio signal) x 10 M H z number of time base reference pulses
The combination of minimum count time of 100 ms and the 10 MHz time base reference assures six-digit resolution.
3-227
Operation Model 8902A
The function of MODULATION OUTPUT/AUDIO INPUT
INPUT key. The connector has an input impedance of approximately 100 kn.
AUDIO
DEMODULATOR
AUDIO FILTERS
AND GAIN AUOlO
COUNTER COUNTER DISPLAY
I
A iidio Freqiitvwy Block Dicigram
COMMENTS
Relative Measurements
If audio frequency is to be displayed relative to a reference, enter the value the Ratio function. (Refer to Ratio
as a ratio reference using
Finer Resolution for Frequencies from 100 to 250 kHz
Special Function 32.1 enables a resolution of measurements, this special function enables displayed resolution of 0.01 instrument power down. dB. a
0.1 Hz for frequencies resolution of 0.001 dB instead of the normally
The selection of Special Function 32.0 or
100 to 250 kHz.
32.1 is maintained through
32.0 Audio frequency
250 kHz. is displayed with the normal resolution of 1 Hz for frequencies from 100 to
32.1 Audio frequency is displayed with a resolution of 0.1 Hz for frequencies from 100 to 250 kl Iz.
32.2 Displays 0 if the normal measurement resolution is enabled (32.0 SPCL) and displays finer resolution is enabled (32.1 SPCL).
1 if a
This spccial function
42.0 is not availablc with firmware datc codcs 234. I985 and bclow. (To display thc firinwarc datc codc. sclcct
SPCL.) To ordcr a ROM scl that contains this spcci,tl function. contcict thc ncarcst HP salcs oflicc.
3-228
Model 8902A Operation
Audio Distortion and Level
FUNCTIONS
AUDIO DISTN, 1 kHz DISTN, 400
Audio RMS Level)
Hz DISTN, RMS, AUDIO INPUT, Special Function 30 (External
DESCRIPTION
Measure distortion on either internally demodulated audio signals or externally input signals with fundamental frequencies of 1 kHz or 400 of the nominal 1 kHz or 400
Hz. (The fundamental frequency must be within &5%
Hz for accurate measurements.) Once selected, the measurement frequency remains unchanged and is automatically activated each time the audio distortion (or
SINAD) measurement is selected.
Special Function signal applied to
30.0 enables the instriiment to measure the true rms
4 level of an external the MODULATION OUTPUT/AUDIO INPUT connector. (The connector is automatically switched to fiinction nominally 100 kR. as an input upon selection
The maximum measurable input level is of
Vrms.
Special Function 30.0. The true rms level of the internal demodulated audio cannot be measured.) Connector input impedance is
PROCEDURE
To measure distortion on the demodulated audio signal, select AUDIO DISTN (Shift, FM).
To measure distortion on an external audio signal applied to the MODULATION OUTPUT/AUDIO
INPUT, select AUDIO DISTN (Shift, FM) and AUDIO INPUT. (Only the true rms detector can be used for these measurements.)
To change the measurement bandwidth of the internally demodulat.ed audio signal, Select the desired filter keys. (Refer to Audio Filfiir.s
If measurements are to be made on a measurements are to be made on a
1
400 Hz audio signal, select audio signal, select
1 kHz
400
DISTN (Blue Key, PEAK+). If
Hz DISTN (Blue Key, PEAK-).
To measure the true rms level of an audio signal applied to the MODULATION OUTPUT/AUDIO
INPUT, select 30.0 SPCL.
HP-IB PROGRAM CODES
AUDIO DISTN=S2
AUDIO INPUT = AI
MODULATION OUTPUT = A0
1 kHz DISTN = D5
400 uV
Hz DISTN
LOG results = mV units = MV units = UV
=
LIN results = LN
LG
D6
VOLTS units = VL
SPCL = SP
3-229
Operation Model 8902A
MEASUREMENT TECHNIQUE
To measure audio distortion, the instrument compares the input signal level measurement made with a true rrns detector harmonic distortion is then calculated as the ratio of the signal with its fundamental removed unfiltered signal. to the same measurement made with the fundamental component removed. Total to the
The broadband audio signal has approximately 55 is switched through a notch filter set to the fundamental frequency dB rejection at the notch frequency with is computed as the ratio of the signal from the output of
(1
10% kHz or 400 Hz).
The distortion the notch filter to the signal without filtering.
The function of the MODULATION OUTPUT/AUDIO INPUT is controlled by the AUDIO JNPUT key. The connector has an impedance of approximately when used as an output.
100 k 0 when used as an input and 6000
The true rms level (from OV to 4V) of any external audio signal (from
INPUT connector always functions as an input.)
20 Hz to 40 kHz) can be measured using the same rms detector. (In this mode, the MODULATION OUTPUT/AUDIO
DEMODULATOR
AND GAIN DISTORTION
ANALYZER
AUDIO RMS
DETECTOR
VOLTMETER
AN0 DISPLAY
1 8 8 8 8 8 8 8 8 8 8 8 1
3-230
Airio Distortion and Levd Block Diagram
COMMENTS
Audio Level Measurement in Watts
Selection of watts as the unit for audio level measurements results in an error.
Automatic Selection of RMS and PRE DISPLAY
Selection detector and sets
3-187.)
of
an audio distortion or level measurement automatically selects the true rms audio
FM de-emphasis to the pre-display mode. (Refer to FA4 Dtwnphasis on page
The SINAD measurement mode (Special Function measurement mode. to SINAL)
29) is almost identical to the audio distortion
SINAD, as measured by the instrument, is the reciprocal of distortion. (Refer
Model 8902A Opera tion
Relative Measurements
If audio distortion reference by selecting level are to be displayed relative to a reference, enter the value as in either linear units (mV, Yo,
(Refer to etc.) or
Ralio
a ratio
The measured results can be displayed logarithmic units (dBV, dB, etc.) using previously selected units are reinstated whenever an audio measurement is the LOG/LIN selected. key. The
3-23 I
Model 8902A Operation
SINAD
FUNCTIONS
1 kHz DISTN, 400 Hz DISTN, Special Function 29 (SINAD)
DESCRIPTION
Special Function 29.0 enables the Measuring Receiver to make tion) measurements. The SINAD the result is expressed differently.
SINAD (Signal to Noise And Distor- measurement is identical to the audio distortion measurement: but
SINAD is often measured as part of receiver sensitivity testing.
SINAD can be measured on audio signals with fundamental frequencies of either 1 kHz
Hz using the 1 kHz DISTN or 400 Hz be within f 5 Y o of the nominal 1 kHz
DISTN or or 400 keys respectively. The fundamental frequency must
400 Hz for accurate measurements. Once selected, the measurement frequency remains unchanged and is automatically activated each time the audio distortion) measurement is selected.
SINAD (or
SINAD can also be measured on an external audio signal applied to the MODULATION OUTPUT/
AUDIO INPUT connector using the AUDIO INPUT key. When external audio is not selected, the instrument measures the SINAD on the internal demodulated audio.
PROCEDURE
To measure SINAD on the demodulated audio signal, select 29.0 SPCL.
To measure SINAD on an external audio signal applied to the MODULATION OUTPUT/AUDIO
INPUT, select 29.0 SPCL and AUDIO INPUT. (Only the true rms detector can be used for this measurement.)
To change the measurement bandwidth of the internally demodulated audio signal, select the desired filter keys. (Refer to Airdio Fi1lcv-s
If measurements are measurements are to to be made on be made on a a 1 kHz signal. select
400 Hz
1 audio signal, select kHz
400 Hz
(Blue Key,
DISTN
PEAK+). If
(Blue Key, PEAK-).
The measured results can be displayed in either linear units (Oh) or logarithmic units (dB) using the LOG/LIN selected. key. The previously selected units are reinstated whenever an audio measurement is
HP-IB PROGRAM CODES
AUDIO INPUT = A I
MODULATION OUTPUT = A0
1 kHz DISTN = D5
400 HZ DISTN = D6
LIN results = LN
LOG results = LG
SPCL =
SP
MEASUREMENT TECHNIQUE
To measure SINAD, the instrument compares the input signal level measured by a true rms detector to the same measurement with the fundamental component removed. SINAD is then calculated as
3-233
Operation Model 8902A the ratio of the unfiltered signal to the signal with its fundamental removed. Refer to the measurement technique discussions in Audio Dislortion and Lcvd
COMMENTS
Relative Measurements.
If SINAD is to be displayed relative to
RATIO key. (Refer to a reference, enter the value as
Ralio
a ratio reference using the
SINAD Response Time.
A slower response time can be selected with Special Function 5. The slow response time improves measurement readability on unstable or noisy signals whenever display jitter is excessive.
The slow response time for SINAD is not available with firmware datc codes 234.1985 and bclow. (To display the firmware date codc. sclcct 42.0 SPCL.) To ordcr a ROM sct that contains this spccial function. contact thc ncarcst HP salcs oficc.
3-234
Model 8902A Operation
Additional Capabilities Contents
FUNCTIONS THAT CAN BE USED WITH MANY MEASUREMENTS
Automatic Operation
How to cancel special functions
Instrument Preset
How
What the default conditions are.
Range Hold
Limit
0
0
0
0
0
0
0
Store/Recall
0
How
How
How to to
Ratio and Log/Lin to to
.................................................................................... or automatically tune the instrument. preset the instrument to its default state.
...................................................................................... set limits on measurements being made.
.............................................................................................
How to access the instrument's 8 storage registers.
.3-237
.3-239
.3-243
.3-245
.3-249
.3-253
FUNCTIONS THAT INCREASE MEASUREMENT CAPABILITIES
Frequency Offset Control
IF Gain
0
0
0
0
0
How
How
How
How improve measurement sensitivity.
How to to to to to
............................................................................... extend the frequency range of the instrument into the microwave region using an external down-converter.
Filters, R F and IF
0
How to insert the RF high-pass filter in the RF signal path to eliminate interfering, low- frequency signals.
.................................................................................................. select IF gain
R F Input Attenuation and Gain
......................................................................... select R F input attenuation or amplification to eliminate input overload or
Error Message Disable Control
.......................................................................... disable or enable combinations of Errors usable measurement range.
01 through 04 to to extend the instrument's
.3-255
.3-259
3-263
.3-265
.3-267
3-235
Model 8902A Operation
Automatic Operation
FUNCTIONS
AUTOMATJC OPERATlON
DESCRIPTION
The Automatic Operation function fulfills two major functions: (1) To configure the Measuring
Receiver to automatically tune to the largest detectable measurement. (2) To cancel most special functions.
RF inpiit signal and to make the selected
Specifically, Automatic Operation sets special functions with prefixes 1 through 10 to their 0-suffix state, cancels many special functions with prefixes greater than 10, and overrides all service special functions (prefixes functions
HOLD,
1
0, through
40,
39. or greater). (Refer to
Refer to Section 8
Special J'unc/ion.s
1 for details on special of the Service Manual for details on Service Special
Functions.) Automatic Operation also cancels some front-panel settings (TRACK MODE, RANGE and DISABLE ERROR.
Those features that are not affected by Automatic Operation include also not affected.
HP or LP FILTERS, FM DE-
EMPHASIS, MEASUREMENT, CALIBRATION, DETECTOR, DISPLAY, and RATlO. R F level- and modulation-related calibration factors remain intact. Limit settings (Special Function 14) and
Frequency Offset Control (Special Function 27) are
PROCEDURE
To enter the Automatic Operation mode, select Automatic Operation. The instrument will immediately re-tune to the input signal and make the measurement selected.
HP-IB
PROGRAM
CODE
AUTOMATIC OPERATION = AU
COMMENTS
Input/Output Status
MODULATION OUTPUT/AUDIO INPUT is blanked temporarily during the automatic tuning process initiated by selecting Automatic Operation.
The Value of the Automatic Operation Capability
Automatic Operation is the easiest way carrier is to make measurements in applications where only a single present at the R F INPUT. The instrument configures itself to meet the needs of most measurement situations, and all error messages signaling inaccurate measurements are enabled.
Range Hold is Opposite to Automatic Operation
The converse of the Automatic Operation mode is the Range Hold function.
Restrictions on Entering Automatic Operation
The instrument cannot enter the Automatic Tuning mode when making any tuned R F level measurements.
3-237
Model 8902A Operation
Instrument Preset
FUNCTIONS
Includes all Power-Up and Default Conditions and HP-IB Clear
DESCRIPTION
When first turned on (during power-up), the Measuring Receiver passes through a sequence of internal checks before it is ready to make measurements. The results of these checks are indicated internally as a service aid. (Refer to Section 8.) The running to the user by lighting all front-panel indicators (burned-out approximately 10 seconds, this sequence is completed.
LEDs are evident at this time). After
When the Instrument Preset key is pressed, the instrument configures itself the same as during power-up, but bypasses the internal checks.
The Measuring Receiver contains a battery back-up to its internal memory, which makes part of the memory non-volatile afler the power has been switched is unplugged. off
Information retained after power-down:
0
The 8 instrument states stored in the Store/Recall registers.
0
For R F Power: a. One set of zero and calibration (SAVE CAL) data. b. One tdble of 16 frequency/calibration factor pairs and the reference calibration factor used with R F power sensors. o c. One table of 22 frequency/calibration factor pairs and the reference calibration factor used with microwave power sensors in the Frequency Offset mode. d. The state of Special Function 32.0 or 32.1 (dB and frequency resolution).
For Tuned RF Level: a. Four calibration factors. b. The frequency at which the calibration factors are valid. c. The state of the R F High-Pass Filter, Wide IF Filters, and Narrow IF Filters at the time of calibration (Special Function 3). d. The state of Special Function 1.0 or 1.9 (RF input attenuator and gain). e. The state of Special Function 32.0 or 32.1 (dB and frequency resolution). t
For AM and FM:
An A M calibration factor and an FM calibration factor (both in disabled mode).
3-239
Operation Model 8902A
Default conditions after power-up or instrument preset:
If no signal is present at the INPUT connector and no HP-IB controller is connected, the measurement conditions and front-panel annunciators are as follows:
Measurement Conditions
Tuning
Measurement Mode:
Modulation Oiitpiit/A~dio Input: Blanked
Calibration Mode:
HP-IS:
Special Functions:
Automatic Signal Search
Frequency
Off
(See “COMMENTS”.)
(See below.)
If a suitable signal is present at the INPUT connector and no HP-IB controller is connected, the measurement conditions, front-panel annunciators. and Special Functions are as follows:
Measurement Conditions
Tuning:
Measurement Mode:
I F Frequency:
Modulation Output/Audio Input:
High- Pass Filter:
Low-Pass Filter:
Calibration Mode:
HP-IB:
Special Functions:
Special Functions
1-10:
11 Previous Ratio:
Ratio Reference:
14 Limit:
Upper Limit:
Lower Limit:
UpperlLower Limit Code:
I6 AM Calibration Factors:
17 FM Calibration Factors:
22 Service Request:
Status Byte:
25 External Attenuation:
26 Set Reference:
27 Frequency Offset Control:
37 Calibration Factors, R F Power
Mode:
38, 39 Calibration Factors,
Tuned R F Level:
Automatic, Low-Noise
Frequency
Automatic Selection
Output FM
All
All
Off
OfT( 15 kHz
(See below.) if inpiit<lO
Off
(See “COMMENTS”.)
MHz) suffix
Off
100%v
Off is set to 0
1300
0.150
0.005 (FREQ) lOO?h or previous power-down value
100% or previous power-down value suffix set to cleared
0 dB
0 dBm
2
0 MHz
[both calibration factor tables from previous power-down]
Automatic Cal Factor Mode
4 calibration factors and R F and IF filters from previous power-down
3-240
Model 8902A Operation
PROCEDURE
To cause the instrument to run through its internal checks and reset the instrument to its default state. turn the instrument off, then on again.
To
INSTR PRESET (Blue Key, AUTOMATIC OPERATION), or issue a device clear command from an HP-IB controller.
To initiate the internal power-up checks, select 40.0 SPCL.
HP-IB PROGRAM CODES
INSTR PRESET (Device Clear) = IP
SPCL = SP
The instrument can on page 3-?5.) also be preset using the device clear bus command. (Refer to the Rcmoie section
COMMENTS
Setting the Instrument to a Known State.
The Instrument Preset feature is a very simple means of setting the instrument to a known state when writing test procedures involving the Measuring Receiver.
Losing Instrument States with a New Controller Assembly.
After plugging in a new controller Assembly, some or all of the instrument states stored through power-down may be non-existent. If this information is lost: a. The Recall function reverts to the Instrument Preset state. b. The R F Power measurement will: (1) display Error 15, (2) light the UNCAL and RECAL annunciators, and (3) use the default zero and calibration factors. (The R F power calibration factors must be re-entered.) c. The calibration factors for Tuned RF Level will be displayed as O.Oo/o (using Special
Function 38). d. AM and FM calibration factors will be
17).
100% when enabled (using Special Fiinction 16 or
Instrument Preset Clears Pending Require Service Messages.
When the instrument is preset, any pending Require Service Message refer to Receiving the Clear Message, in Remote Operation.) is cleared. (For more details,
CLEAR Key.
The HP-IB Clear message should not be confused with the front-panel CLEAR key or its CL HP-
1B code. The HP-IS Clear message presets the instrument. The CLEAR key clears the display and returns the instrument to its previous state.
Alternative to Turning the Instrument Off and then On.
Lse speciai fiinction 40.0 to cause the Measuring Receiver to pass through its internal checks. (Special function 40.0 is not accessible from the HP-1B.)
3-24 I
Model 8902A Operation
Range Hold
FUNCTIONS
RANGE HOLD
DESCRIPTION
1
The Range Hold function freezes the current ranges being used by the Measuring Receiver. This function, the converse of Automatic Operation, disables automatic tuning and sets Special Functions prefixed I, 2, 3, 7, 9, and 10 to the current range settings. The following functions are not affected by Range Hold: High-pass and Low-pass Filters, FM De-emphasis, Measurement, Detectors, and
Display. Special Functions prefixed I through 10 that are already manually set are unaffected. The table below summarizes the effect of the Range Hold feature:
Special Function
Prefix
1
I
I
Measurement Function
I
RF Input Attenuation and Gain
~
I
I
on
HOLD
Functions
Holds setting
~ ~~ ~~ r
Holds setting 2 Audio Range
3 RF and IF Filters Holds setting
Tuned RF Level Display Averaging No effect
6
7
4
5 Audio Detector Response
AM ALC Response
RF Frequency Resolution
No effect
No effect
Holds setting
-~
8
~~~
9
~
Error Message Disable
~ ~
IF Gain
~ ~ ~~ ~ ~
No effect
~~
Holds setting
10 RF Power Range
AUTO TUNING
Holds setting
Selects Manual Tuning
PROCEDURE
To hold instrument settings in a specific measurement state, set the Measuring Receiver as desired, then select RANGE HOLD.
To exit the Range Hold mode, select RANGE
OPERATION.
HOLD a second time or select AUTOMATIC
HP-IB PROGRAM CODE
Automatic Ranging = GO
RANGE HOLD = GI
3-243
Operation Model 8902A
COMMENTS
Altering Held
Functions.
Once settings are held with the Range Hold function, they can be altered by manually entering the desired setting. For example, the Range Hold fiinction places the instrument in the manual tune mode; select AUTO
Similarly, Special Functions can be used to set other functions operation.
TUNING (Blue Key, TRACK MODE) to re-enter the automatic tuning mode. or selectively return them to automatic
3-244
Model 8902A Operation
Ratio and Log/Lin
FUNCTIONS
RATIO, PREVIOUS RATIO, LOG/LIN, Special Function 1 1 (Previous Ratio)
DESCRIPTION
The Ratio and Previous Ratio fiinctions permit any measurement result the current ratio reference. to be scaled to a reference.
The reference may be either a measurement result or a keyboard entry. Special Function I 1.2 displays
The LOGILIN key enables measurement results to be displayed in linear or logarithmic units, both absolute and relative. Examples of absolute units are kHz and mV (linear), or dBm (logarithmic).
Examples of relative units are
O/O and dB. For purposes of discussion, basic measurement units, such as Yo for AM or distortion, dB for SINAD, etc., (though actually relative units), are treated as absolute units. When the instrument displays
O/o and dB as relative units (that used), annunciator REL is added to the display. is, when the ratio function is
All modulation and all frequency measurement results cannot be displayed with absolute, logarithmic units even though they can be displayed in relative, logarithmic units. (The LOG/LIN key is ignored.)
The Ratio function can be used with the following measurements:
AM
F M
9 M
R F POWER
FR EQ
AUDIO FREQ
AUDIO DISTN
IF LEVEL
TUNED RF LEVEL
FREQ ERROR
SlNAD (29.0 SPCL)
Ext Audio RMS Level (30.0
LO Frequency (33.0 SPCL)
IF Frequency (34.0 SPCL)
R F Level (35.0 SPCL)
SPCL)
Peak Tuned RF Level (36.0 SPCL)
The Ratio fiinc!ion is exited when:
0
0
0 the RATIO key is pressed a second time, a new measurement is selected, or other measurement units are selected.
PROCEDURE
Select LOG/LIN anytime during a measurement to change the display between linear and logarithmic units, where permitted. for both absolute and relative (Ratio) displays.
To use the Ratio function:
1. Select the desired Measurement mode. Measurements possible with the ratio fiinction are listed in “DESCRIPTION.”
3-245
Operation Model 8902A
2. Set the display to the dcsired reference value, either
0
0 adjust the signal parameter being measured for a display equal to the desired reference, or enter the refcrence on the numeric keys. (If the reference value is to be negative, select minus; that is, the Blue Key, then the decimal key.)
3. Select RATIO. The display will show the measurement result relative to the reference.
To use the Previous Ratio fiiiiction to restore a previously-entered ratio reference:
1.
2.
Select the desired Measurement mode.
Select PREVIOUS reference regardless
RATIO (Blue Key, RATIO). The display will show the measurement of what Measurement the instrument was in when the ratio reference was entered and regardless of the current Measurement mode.)
To 11.2 SPCL.
EXAMPLES
LOCAL
(keystrokes) r
(program
codes)
The displayed measurement result is 100% REL if linear units are selected or 0 dB if logarithmic units are selected. (The display will normally vary about these nominal values due to noise and the typical one-count uncertainty in the measured result.)
REL
If it is desired to scale FM measurement results relative to 50 kHz, set the Measurement mode to
FM:
-DATA
7
OISPUY
9
LOCAL
(keystrokes) uu
(program codes) Data
50 R1
T-L_,
Display
If, as in the previous example, 35.35 kHz FM deviation was measured, the displayed measurement result will be 70.79'0 REL if linear units are selected or -3.01
dB
REL if logarithmic units are selected.
3-246
Model 8902A Opera tion
HP-18
PROGRAM
CODES
LOG =
=
LG
LN
PREVIOUS RATIO = R2
RATIO off
SP
=
RATIO on =
SPCL =
R1
MEASUREMENT TECHNIQUE
In the Ratio mode, measurements are made in the same way as when not in the Ratio mode: however, before the result is displayed, the internal controller converts it to ratio. The following equations are used for computing ratio:
(M/R) (100%) = % ratio for all measurements,
(20) log (M/R) = dB ratio for the following measurements:' AM
LEVEL, SINAD (29.0 SPCL), Ext Audio RMS Level, and following measurements:2 FREQ, AUDIO FREQ, FREQ ERROR,
IF Frequency (34.0 SPCL),
(IO)
FM, @M, AUDIO log (M/R)
LO
= dB ratio for the
Frequency
DISTN, IF
(33.0 SPCL), where M is the (undisplayed) measurement result and R is the ratio reference.
COMMENTS
Input/Output Status.
The output signal at MODULATION OUTPUT/AUDIO INPUT is unaffected by the Ratio fiinction.
Displaying the Reference.
When using a currently-displayed measurement result
1 I.?. as the ratio reference, that result actually becomes the reference. The only way to read this reference then is to display it via Special Function
Display Flickw.
Since displayed measurement results are computed from the actual physical measurements, least- significant digit flicker in displayed result. between 100.0%
For the physical measurement can often lead to larger apparent example, an AM measurement varying between and 100.2°/0 REL with swit.ching to logarithmic units). a ratio reference of 50 (or
50.0% between and
0.00 flicker in the
50.10/0 will vary and 0.02 dB after dR Ratio.
When using dB ratio; any ratio reference or measurement result that causes ratio M/R (refer to previous equations) to equal 0. results in a display of Error 11 since the log of 0 is undefined.
When uV. mV. or V units arc uscd, this equation provides the ratio result for RF POWER, TUNED RF LEVEL. and RF
LEVEL (35.0
When watts units are uscd. this equation provides the ratio result for RF POWER, TUNED RF LEVEL, and RF LEVEL (35.0
SPCL) measurcmcn!s.
3-247
Operation Model 8902A
Finer Resolution for dB Measurements
Special Function 32. I enables a special fiinction enables a resolution of 0.1 Hz
0.00 I dB. For audio frequency measurements, this for frequencies from 100 to 250 kHz instead of the normally displayed resoliition of 1 Hz. The selection of Special Function 32.0 or 32.1 is maintained through instrument power down.
32.0 Power is displayed with the normal measurement resolution of 0.01 dB.
32.1 Power is displayed with a measurement resolution of 0.001 dB.
32.2 Displays resolution
0 if the normal measurement resolution is enabled (32.0 SPCL) and displays 1 if a finer is enabled (32.1).
Use SET REF for Relative Tuned RF Level Measurements.
The SET REF key should be used to make scaled measurements in the Tuned R F Level Measurement mode. (Refer to Attcnuafor Mcwsirrc.mcnts
15).
Modulation Flatness.
When used in conjunction with track mode tuning, the Rat.io function makes checking modulation flatness with respect for a to R F freqirency very convenient. (Refer discussion of track mode tuning.) to
Rf-'
Setting Measurement Limits.
The ratio reference can also be entered as a limit reference. (Refer to Limd
Common Ratio Measurements.
The following list provides some usefiil references for common ratio measurements:
0
0
To display broadcast FM deviation relative to the common standard of 75
75 and linear units. l o display
0
To display AM as dB down from the carrier, enter a value of 200 and select logarithmic units.
0
To display rms calibrated average as true average, enter a value of 1 11.07 and select linear units.
0
To display rms calibrated average as peak, enter a value of 70.7 and select linear units.
This special function is not availdblc with firmware datc codcs 234.1 985 and below. (To display the firrnwarc dalc code. sclect
41.0 SPCL.) To ordcr a ROM sct that contains this spccial function. contact the ncarcst HP salcs officc.
3-248
Model 8902A Operation
Limit
FUNCTIONS
RATIO, Special Function 14 (Limit)
DESCRIPTION
Using Special Function 14 and the RATIO key, lower and upper measurement limits can be entered into the Measuring Receiver. Subsequent out-of-limit measurements will then cause the LIMIT annunciator to light.
Wheii the Limit feature service request upon reaching a lower or upper limit (Refer
page 3-27.) 'The LIMIT light turns
off five measurement cycles after the condition causing limiting is cleared. is enabled, the Measuring Receiver can be configured to issue an HP-IB to the Rcrnofc section in this manual on
Only one lower and one upper limit can be set. Once a limit has been set, it can be used only for that
Measurement mode. (However, one limit can be used for one Measurement mode, and the other limit for another Measurement mode.) If, after setting limits, another Measurement mode is selected, the Limit feature is deactivated, but it is restored automatically when the former Measurement mode is re-entered.
Both limit references can be displayed, cleared, and restored; the status of the Limit function can be displayed; and the Measurement modes for which the limits were set can be displayed.
PROCEDURE
To estabiish a ratio reference and set it as a limit:
First enter thc desired limit reference that ratio referen.ce: as a ratio reference and then set the lower or upper limit to
1. Select the Measurement mode for which the limit is to be used.
2. Key in the reference value followed by the RATJO key will s a y as currently displayed.)
(Blue Key and the decimal point key.)
(Do
To change the sign of the reference, use the minus (-) key
To set the limits:
3. Set the lower limit (14. I SPCL) or the upper limit (1 4.2
4. To display the measurement result in absolute units, select RATIO again.
3-249
Operation Model 8902A
The Special Function codes pertaining to the Limit function are listed in the following table:
I
Action
Special Function
Code
Program Code
Limit
Clear limits; turn off LIMIT annunciator.
Set lower limit to RATIO reference.
Set upper limit to RATIO reference.
Restore lower limit.
Restore upper limit.
Display lower limit.
Display upper limit.
Display selected, lower limit measurement code.
Display selected, upper limit measurement code.
Display limit status in the format Lower.Upper; where O-disabled and 1 =enabled.
14.0 SPCL
14.1 SPCL
14.2 SPCL
14.3 SPCL
14.4 SPCL
14.5 SPCL
14.6 SPCL
14.7 SPCL
14.8 SPCL
14.9 SPCL
14.0SP
14.1 SP
14.2SP
14.3SP
14.4SP
14.5SP
14.6SP
14.7SP
14.8SP
14.9SP
To
SPCL effect, select 14.7 SPCL or 14.8 (respectively). The displayed code represents the measurement in which the limit is in effect. These codes are indexed in the following table:
[
Display
0.000
0.001
0.002
0.003
0.004
0.005
0.006
0.008
0.009
0.01 0
~~
I
Measurement
~
AM
FM
4M
RF POWER
TUNED RF LEVEL
FREQ
FREQ ERROR
IF LEVEL
AUDIO FREQ (internal)
IF FREQUENCY (34.0 SPCL)
~~ ~
Display
0.01 1
2.003
2.004
2.009
2.01 0
2.01 1
4.009
4.01 1
6.01 1
I
Measurement
AUDIO FREQ (external)
RF LEVEL (35.0 SPCL)
PEAK TUNED RF LEVEL (36.0 SPCL)
AUDIO DISTN (internal)
LO FREQUENCY (33.0 SPCL)
AUDIO DlSTN (external)
SINAD (internal)
SINAD (external)
EXT AUDIO RMS LEVEL (30.0 SPCL)
1
3-250
Operation Model 8902A
EXAMPLE
To an upper limit of 75 kHz FM deviation:
. -
(program codes)
I
I
Measurement
Data
D
M2 75 R114.2 SP s I a y
TJ T
T
=
RO
RATIO reference
Code Display
Function
LExit RATIO J
I
Read the FM deviation in kHz with an upper limit set at 75 kHz.
HP-18 PROGRAM
CODES
The codes for performing the various limit operations are provided in “Procedures”.
RATIO off =
RATIO on =
RO
R1
COMMENTS
Relative Limits Not Possible.
The test for out-of-limit results is performed of relative measurement results. on the actual measurement results, not upon the displayed number, Thus, if the Ratio feature is enabled simultaneously with the Limit feature, the limit test is still based on the measurement result, not the computed ratio. Limits cannot be terms set in
Importance of Key Sequence.
If Special Function 14.1 or 14.2 is initiated with no previous numeric value. the ratio reference becomes the entered value. The desired limit must be entered before the Special Function numeric code.
3-25 I
Model 8902A Operation
Store/Recall
FUNCTIONS
STORE. RECALL
DESCRIPTION
The Measuring Receiver can store a complete instrument stat.e (including all front-panel functions and most Special Functions) in any of its eight storage registers. The stored data is retained in non- volatile memory when the instrument is stored states can then be re-initiated. off even when the power cord is removed. Any of these
PROCEDURE
To store the current instrument state, select STORE (Blue Key, 7). Then key in a register number (1 through 8).
To recall a previously-stored instrument state, select RECALL (Blue Key, 8). Then key in the desired register number (1 through 8).
HP-IB PROGRAM CODES
RECALL = RC
STORE = TR
COMMENTS
Regarding storage of RF power calibration factors:
.The current reference calibration factor and the frequency/calibration-factor pair can be stored.
.Manual calibration factors can be stored.
.The table of calibration factors cannot be stored with this function, but two tables of calibration factors can be separately stored in the instrument's non-volatile memory. (Refer to RF Power under
3-253
Model 8902A Operation
Frequency Offset Control
FUNCTIONS
Special Function 21 (Frequency Offset Control)
DESCRIPTION
Using an external mixer and local oscillator (LO) to down-convert the input signal, the frequency range of the Measuring Receiver can be extended into the microwave region. The Frequency
Offset mode allows the Measuring Receiver to keep track of the frequencies involved in the down- conversion so the user can be freed from this task. This feature operates for frequencies up to 42
GHz.
The full complement of instrument measurements can be made on the down-converted microwave signal (with the same signal restrictions that apply in the normal frequency range). For best measurement accuracy, the external LO should be a source free from microphonics, residual FM, and drift since these signal impurities translate directly on to the down-converted signal. Use of a synthesized signal source is recommended. Examples of suitable signal sources are the HP 8340A,
8612A, and 8613A.
The RF Power measurement mode uses a separate table of frequencies and calibration factors in the
Frequency Offset mode. Frequency entries can range from 0 to 110 GHz. (Refer to
for a procedure for entering calibration factors.)
RF
Power on
A rear-panel FREQ OFST TTL OUT connector can indicate to external circuits whether the
Measuring Receiver is in the Frequency Offset mode and whether the LO is above or below 18
GHz. Use this feature to control external RF switches to route or bypass the input signal between external mixers.
Use Special Function 27 to enter and exit the Frequency Offset mode and to enter and display the
LO frequency.
PROCEDURE
To down-convert a microwave input signal into the range of the Measuring Receiver, set an external microwave signal source to a level suitable as an LO for the external mixer. Set the frequency of the external LO source to within 1300 MHz of the microwave input signal. Connect the external LO source to the L port of the external mixer. Connect the microwave input signal to the appropriate input port of the external mixer. Connect the output port of the mixer to the RF INPUT connector or to the input of a sensor module connected to the Measuring Receiver.
Key in 27.3 SPCL then select the LO frequency (in MHz) and select MHz to enter the Frequency
Offset mode. rcwIFEBRUARY86 3-255
Operation Model 8902A
The following table summarizes the various Frequency Offset Control special functions:
Action Regarding Frequency
Offset Control
Exit Frequency Offset Mode
Re-enter Frequency Offset Mode
Display the External LO Frequency
Enter and Enable the LO Frequency.
Special Function
Code
27.0 SPCL
27.1 SPCL
27.2 SPCL
27.3 SPCL
Program Code
HP-I8
27.0SP
27.1 SP
27.2SP
27.3SP
‘After Special Function 27.3
40700 MHz can be entered. is entered, enter the frequency of the LO (in MHz) Frequencies from 0 to
3-256
Having entered the appropriate LO frequency, either manually tune
Receiver automatically tune to the input signal. to the microwave input frequency by pressing the appropriate numeric keys followed by the MHz key or let the Measuring
Perform instrument measurements as usual. Select the microwave input ryequency.
DISPLAY FREQ (Blue Key, kHz 1) to display
HP-IB PROGRAM CODES
All HP-IB codes for innnipdating the frequency offset control using Special Function 27 are provided in “Procedures”.
DISPLAY FREQ = FR
MHz = MZ
MEASUREMENT TECHNIQUE
The external input to
LO mixes with the microwave input signal the Measuring Receiver. The frequency of the microwave input signal must
MHz of the external frequency is manually entered by the operator using Special Function thereafter, uses that
LO to
LO the actual frequency of the be within the measurement range of the Measuring Receiver. The frequency
LO. to create a difference frequency which is the
27.3. be within 1300
LO
The Measuring Receiver, to compute the microwave input signal frequency regardless of
If tuning is in the automatic mode, the Measuring Receiver computes and displays the microwave input frequency as
(frequency of LO) - (frequency at INPUT).
If tuning is manual, the Measuring Receiver computes and displays the microwave inpiit frequency as:
(frequency of LO)
The difference is computed when the manually-entered frequency is less than the LO frequency. The sum is computed when the frequency is greater. The sense (+ or -) of the math operation remains the same regardless of the actual microwave input frequency, even if automatic tuning is selected.
The displayed frequency is always based on the frequency actually at the Measuring Receiver’s input and not the manually-entered input frequency, which serves only to set the Measuring Receiver’s internal LO. Manually entering a new microwave inpiit frequency, entering a new initiating automatic tune always retunes the Measuring Receiver.
LO frequency, or
When the manually entered LO frequency is displayed (Special Function preceeding the frequency indicates that the math operation is a sum.
27.2), a minus (-) sign
Model 8902A Operation
COMMENTS
Range Limitations.
If the entered LO frequency and microwave input frequency differ by more than 1300 MHz (or less than 0.15 MHz), an out-of-range error is displayed (Error 10). (Even though the Measuring Receiver appears to measure signals over the range 0 to 110 GHz, the instrument itself can tune to and measure signals only over the range of 0.15 to 1300 MHz. An exception to this is the RF Power measurement.)
Default Condition.
At power-up, the math operation (described under “MEASUREMENT TECHNIQUE”) is a difference.
Peak+ and Peak- Functions Reversed.
When FM or the external
@M
LO measurements are made, the Peak+ and Peak- functions are reversed whenever frequency is less than the microwave input frequency.
HP-IB: Service Request Mask.
Using Special Function 22 (bit weight 16), the Measuring Receiver can be unmasked to output a
Service Request whenever the Frequency Offset mode changes state (that is, entered or exited) or when the instrument is manually retuned. (Refer to the Rernufe
FREQ OFFSET TTL OUT.
When the Measuring Receiver is in the Frequency Offset mode, the rear-panel FREQ OFFSET TTL
OUT connector outputs a voltage which is dependent upon the state of the Frequency Offset mode and the entered external LO frequency. The state of the output is shown in the following table:
State of Frequency
Offset Mode out
In
In
In
Entered LO Frequency
>O
>18
(GH4
Any
0 but but
5
40.7
Nominal Voltage at
FREQ OFFSET TTL OUT
0
0
+5
+3 rcv. 1 FEBRUA R Y86 3-257
Model 8902A Operation
Filters, RF and IF
FUNCTIONS
Special Function 3 (RF and IF Filters)
DESCRIPTION
RF Filter.
To eliminate unwanted low-frequency signals in the RF signal path, an RF filter can be inserted.
Special Function 3 manually selects the 5.25 MHz High-Pass Filter. Since the IF generally responds to signals below input. (For
2.5 MHz, the filter eliminates any low frequencies that might be present on the input signals between 150 kHz to 10 MHz, the filter should be switched out.)
IF Filters.
The Measuring Receiver down-converts (heterodynes) the R F input to the IF. The IF is usually centered at 1.5 MHz for input signals 10 to 1300 MHz. (An IF of 455 kHz can be manually selected.)
For signals between 2.5 MHz and 10 MHz, the IF is 455 kHz. Below 2.5 MHz, the signal is passed directly into the IF without down-conversion (unless the 455 kHt IF has been manually selected).
IF filters determine the frequency response of each IF.
When the 1.5 MHz IF is selected, the IF frequency response is determined by the 2.5 MHz Low-Pass
(LP) Filter.
When the 455 kHz IF is selected, the Wide 455 kHz Bandpass (BP) Filter determines the IF frequency response, unless a tuned RF level measurement is made which inserts the Narrow 455 kHz in series with the other selected IF filter.
BP Filter
Various combinations of these filters can be manually inserted using Special Function 3. (Special
Function 3 will override automatic filter selection for Tuned RF level measurements.)
3-259
Operation Model 8902A
PROCEDURE
To select key a desired combination of RF and IF filters, or to re-enter the automatic selection mode, in the corresponding Special Function code, then press the SPCL key :
Spec i a
Code
I
Function
3.0 SPCL
3.1 SPCL
3.2 SPCL
3.3 SPCL
3.4 SPCL
3.5 SPCL
3.6 SPCL
3.7 SPCL
3.8 SPCL
1
I
Program Code
3.0SP
3.1 SP
3.2SP
3.3SP
3.4SP
3.5SP
3.6SP
3.7SP
3.8SP
1
I
IF
Frequency
455 kHz
1.5 MHz
455 kHz
1.5 MHz
455 kHz
455 kHz
455 kHz
~
455 kHz
Wide
IF
Filter
Automatic Selection
200 kHz BW
Narrow IF
Filter
(30 kHt BW)
1
~ ~~
: OUT
OUT
~~
~
OUT
~
200 kHz BW
2.5 MHz
Low-Pass
200 kHz BW
2.5 MHz
Low-Pass
~~
200 kHz BW
2.5 MHz
Low-Pass
I
OUT
IN
IN
IN
IN
-1
I
RF High-Pass
Filter
(5.25 MHt)
OUT
OUT
IN
IN
OUT
OUT
IN
IN
HP-IB PROGRAM
CODES
The HP-IB codes for selecting various Combinations of RF and IF filters are provided in
"PROCEDURE".
BLOCK DIAGRAM
NARROW
WlOE 455 kHz
&-
Lilock Diagram oj'R1.' and IF I-illcr.5
VOLTMETER
AN0 DISPLAY
ROR8ORflOQR]
3-260
Model 8902A Operation
COMMENTS
Default Condition.
When the instrument is first powered up or when Automatic Operation or Instrument Preset is selected, R F and IF Filters are placed in the automatic selection mode.
Automatic Retuning.
When a new IF is selected, the instrument immediately retunes.
Increased Sensitivity and Selectivity.
Many measurements can typically be made on very low-level signals. Using the narrow bandwidth of the 455 kHz IF for signal frequencies less than greater than 10 MHz increases the sensitivity and selectivity of the Measuring Receiver. (There are, however, restrictions on modulation, and measurement accuracy may decrease.) Manual deletion of
RF input attenuation or insertion of gain also increases sensitivity. (Refer to and
2.5 MHz (but in the manual down-convert mode) or
R1:
Input A ((cwuation
3-26 1
Operation Model 8902A
IF Gain
FUNCTIONS
Special Function 9 (IF Gain)
DESCRIPTION
For Tuned RF Level measurements, the Measuring Receiver uses a programmable IF amplifier. The amplifier has precise 10 dB gain steps ranging from 0 to 60 dB. The amplifier is automatically inserted and programmed in the Tuned IF Level measurement mode for either the IF Synchronous or IF
Average detector. For other measurements, the IF amplifier is bypassed.
Special Function 9 permits manual section of the IF amplifier and can be used with tuned measurements other than tuned RF level.
PROCEDURE
To manually set the IF gain, or
Special Function code followed by SPCL.
IF Gain
I
Special Function
Code
Program Code
Automatic Selection 9.0 SPCL 9.OSP
0 9.1 SPCL
~~~ ~
10
20
~~
9.2 SPCL
9.3 SPCL
9.1 SP
9.2SP
9.3SP
30 9.4 SPCL 9.4SP
40
50
60
9.5 SPCL
9.6 SPCL
9.7 SPCL
9.5SP
9.6SP
9.7SP
HP-lB
PROGRAM CODES
All HP-IB codes for selecting IF gain ranges are provided in “PROCEDURE”.
3-263
Operation Model 8902A
COMMENTS
Default Condition.
When the instrument is first powered up, or when Automatic Operation or Instrument Preset is selected, the IF Gain fiinction is placed in the automatic selection mode. (The gain will usually change when a different IF detector is selected.)
Multiple Uses
of
IF Amplifier.
The design of the programmable IF amplifier is optimized for the Tuned RF Level measurement mode which uses the 455 measurements and IF frequencies to improve measurement sensitivity. (Refer to the block diagram in Tiined
RF
Levd
kHz IF. The amplifier, although not specified, can be used for all tuned
to aid in visualizing the function of the IF amplifier.)
Measurement Degradation.
Increasing the IF gain fo; measurements other than Tuned R F Level would degrade performance.
Degradation is most evident at high modulation rates, high IF gain, kHZ. or IF frequencies other than 455
IF Gain Change.
The IF gain will generally change when a different IF detector is selected.
3-264
Model 8902A Operation
RF Input Attenuation and Gain
FUNCTIONS
Special Function 1 (RF Input Attenuation and Gain)
DESCRIPTION
The RF input attenuation and gain is usually automatically selected but can be manually keyboard entry using Special Function 1. set by
PROCEDURE
To set the input attenuntion/gain to a selected range, or to enter an automatic selection mode, key in the corresponding special function code, then select SPCL:
RF Gain
RF
Input
I
Attenuation
RF Attenuation
Automatic Selection Automatic Selection
0 dB
10 dB
20 dB
0 dB
30 dB
40 dB
Special Function
Code
1.0 SPCL
1.1 SPCL
1 .OSP
1.1SP
1.2 SPCL 1.2SP
1.3 SPCL 1.3SP
I
1.4 SPCL
I
1.4SP
I I I
1.5 SPCL
I
1.5SP
~
24 dB
24 dB
Automatic Selection
0 dB
10 dB
Automatic Selection with 10 dB attenuation always inserted*
1.7 SPCL
1.8 SPCL
1.9 SPCL
1.7SP
1.8SP
1.9SP
COMMENTS
Default Condition.
When the Measuring Receiver
Function 1 .O). is first powered up, or when Automatic Operation or Instrument
Preset is selected, the RF input attenuation/gain is placed in the automatic selection mode (Special
Error 02, 03.
If the RF input attenuation/gain is manually set overdrive the input mixer, Error 02 is displayed. If the RF input attenuation/gain is manually set so the signal level reaching the IF circuits is too low to a range that causes the input signal level to for accurate measurements, Error 03 is displayed.
3-265
Operation Model 8902A
Manual Settings Not Allowed with RF Level Measurements.
Manual setting of RF input attenuation/gain is overridden when R F Level measurements are selected.
Special Function 1.9.
When Special Function 1.9 (the alternate automatic selection) has been selected, the displayed special function suffix in the Special Display will differ frcm that suffix displayed in the Special Special
Display. (Refer to Special Fiinctions
When the Special Display is initiated, 9
for a will be the first description of these two types of display.) suffix. initiated, the automatically-selected suffix will be displayed.
When the Special Special Display is
Increase Measurement Ability on Low Level Signals.
Use input gain (Special Functions 1.6 and 1.7 that insert the R F Amp) in conjunction with
(Special Function 9) to make general, unspecified RF
IF gain and audio measurements on low-level signals.
Only use input gain for input signal frequencies greater than 1 MHz. The R F and also contribute distortion and noise to the measurements. (Refer to IF Gain
IF Amplifiers could
lOd8
ATTENUATOR RF AMP
OVERPOWER
RELAY
INPUT
ATTENUATOR
INPUT
MIXER
RF PEAK
DETECTOR
~ ~~~ ~
BIock Dingrnm of RF Inpiit Atteniiation and Gain
3-266
Model 8902A Operation
Error Message Disable Control
FUNCTIONS
DISABLE ERROR, Special Function 8 (Error Message Disable and Enable)
DESCRIPTION
Error Messages are one means the Measuring Receiver uses to safeguard measurement integrity.
When the instrument senses a potential error-causing situation, an Error Message code is displayed to alert the user of the condition. The the current errors. (Refer to Error
Error Message code indexes an Error Message, which describes
Siimmary
When the Measuring Receiver is in its Automatic Operation mode, Error Messages are selectively enabled, depending on the measurement being made, measurements. Some Error Messages, however, can be selectively disabled
Function 8. Disable Error performs the same function as Special Function 8.7 (Errors
04 disabled). to assure the broadest range of calibrated or enabled using Special
01, 02, 03, and
Most combinations of Errors the behavior of the instrument to meet a particular set
Function 8.8 (Errors 01 through
(Refer to “COMMENTS” for
01 through
04
04 can be disabled enabled) sets up further elaboration.) or enabled by the operator to customize measurement requirements. Special the Measuring Receiver as a calibrated receiver.
The following table lists the Error Messages conveyed by Errors 01 through 04:
I
Error
I
Error Message
01
02
03
04
Signal out of IF range
Input circuits overdriven
Input circuits underdriven
Audio circuits overdriven
I
3-267
Operation Model 8902A
The following table lists the errors that are arrtomatically disabled in each Measurement mode:
Measurement Selected
~~~ ~ ~~
AM
FM
4M
RF POWER
FREQ
AUDIO FREQ
AUDIO DISTN
IF LEVEL
TUNED RF LEVEL
FREQ ERROR
SINAD (Special Function 29.0)
EXT AUDIO RMS LEVEL (Speical Function 30.0)
LO FREQUENCY (Special Function 33.0)
IF FREQUENCY (Special Funciton 34.0)
RF LEVEL (Special Function 35.0)
PEAK TUNED RF LEVEL (Special Function 36.0)
Errors
Disabled When in
Automatic Selection Mode
(Special Function 8.0)
None
None
None
01,04
02,03, 04
None
None
01, 02, 03, 04
02, 03, 04
01,02,03, 04
None
None
01, 02,03, 04
01,02,03, 04
01,04
02, 03, 04
PROCEDURES
To disable Errors selection enables
01, 02, 03,
8.7 SPCL. and 04, select DISABLE ERROR (Blue Key, RANGE HOLD). This key
To selectively enable or disable combinations of Errors 01 through code that corresponds to the condition desired, then select conditions are listed in the following table:
SPCL. The codes for the various
Error
Condition
Special Function
Code
Program
Code
Automatic Selection
01 disabled
02 and 03 disabled
01, 02, and 03 disabled
04 disabled
01 and 04 disabled
02, 03, and 04 disabled
01, 02, 03, and 04 disabled
01, 02,03, and 04 enabled
8.0 SPCL
8.1 SPCL
8.2 SPCL
8.3 SPCL
8.4 SPCL
8.5 SPCL
8.6 SPCL
8.7 SPCL
8.8 SPCL
8.0SP
8.1 SP
8.2SP
8.3SP
8.4SP
8.5SP
8.6SP
8.7SP
8.8SP
3-268
Model 8902A Operation
HP-IB PROGRAM CODES
The HP-IB program codes for selectively disabling combinations of Errors in “PROCEDURE”.
01 through 04 are provided
DISABLE ERROR = BI
Clear DISABLE ERROR function = BO
COMMENTS
Input/Output Status
When Error Messages are disabled, the accuracy of the displayed measurement and the fidelity of the signal at the output of the MODULATION OUTPUT/AUDIO INPUT are not safeguarded.
When all the errors are enabled, displayed results are calibrated and the output of MODULATION
OUTPUT/AUDIO INPUT is entirely safeguarded.
Disable Error 04 Inhibits Audio Autoranging
When Error 04 is disabled, the Measuring Receiver automatically ranges to a less sensitive range when the signal level requires, but it does not range back when the audio level is reduced. Thus, if a transitory peak audio signal is detected, the Measuring Receiver will up-range the audio range to accommodate the peak but will not down-range after it has passed. Audio autoranging is then prevented from interfering with other measurements such as input frequency. (Refer
to A irdio Rangc
Special Function 8 Overrides Automatic Selection
Nqte that Special Functions 8.1 through 8.8 override the automatic selection for all measurement modes. Thus. error messages that may be appropriately disabled for one measurement mode (such as frequency) may be inappropriate for another measurement mode (such as AM).
Limits to Disabling Error Messages
Disabling some error messages (such as Error be disabled (such as Error 07).
04) often give rise to other error messages that cannot
Safeguarding the Signal Fidelity at the Modulation Output
Special Function 8.8 is sometimes referred to as the “calibrated receiver” mode of operation.
It assures that the output from MODULATION OUTPUT/AUDIO INPUT is safeguarded for most measurements. Some tuned, non-modulation measurement modes (such as frequency) d o not completely safeguard the signal fidelity at this output since accurate demodulation is not the primary goal of that measurement mode.
Identify Currently Disabled Error Messages
Use the Special Display and the Special Special Display to identify currently disabled error messages.
(Refer to Special J‘iinctions
3-269
Model 8902A Operation
Special Functions
FUNCTIONS
All Special Functions prefixed 1 to 39
DESCR I PTlON
General Information.
Special functions enable extended use of the instrument beyond the control normally available from dedicated front-panel keys. The special functions are best used after a thorough understanding of the instrument is grasped.
Special functions are accessed via keyboard entry of the appropriate numeric code terminated by the SPCL key. (Refer to "Procedures".) The codes comprise a prefix, decimal, and suffix.
Special functions are disabled in different ways, depending on the function. Refer to the following comprehensive table for actions which clear or disable any special function. Special functions are grouped by their prefixes into three categories as follows:
Prefix 0
Prefix 0 is the Direct Control Special Function intended for use in servicing the Measuring Receiver
(discussed in detail in Section 8). All instrument error messages and safeguards are inactive. If the
Direct Control Special Function is entered inadvertently, press AUTOMATIC OPERATION.
Prefixes 1 to 39
Prefixes 1 to 39 are the User Special Functions that are used during normal instrument operation when a special configuration, a special measurement, or special information is required. All error messages and most safeguards remain in effect unless the operator disables them. These special functions are described in the table in this instruction.
Prefixes 40 to 99
Prefixes 40 fault (discussed in detail in Section 8). The functions available include special internal measurements, software control, and special service tests and configurations. Most instrument safeguards are relin- quished. If to 99 are the Service Special Functions used to assist in troubleshooting an instrument a Service Special Function is entered inadvertently. press AUTOMATIC OPERATION.
Repair personnel can gain arbitrary control of the instrument as an aid in troubleshooting.
Viewing Special Function States
In addition to completing the entry of special function codes, the SPCL key enables viewing of some special function settings. The operator-requested settings of Special Functions prefixed 1 through 10 can be viewed by pressing the SPCL key once (following no numeric entry). This display is called the
Special Display. If some of these Special Functions are in automatic modes (generally the 0-suffix setting), the actual instrument settings of these functions can be displayed by pressing the SPCL key a second time while the Special Display is still active. This display is called the Special Special
Display. Both displays can be disabled by pressing any key except the Blue Key, LOCAL, key. (While either display is active, pressing the SPCL key selects the other display.) or S (shift)
A summary of User Special Functions is provided at the end of this instruction. and the Special Special Display.
Also included in this instruction are procedures for initiating special functions and for obtaining the Special Display
3-27 1
Operation Model 8902A
PROCEDURES
Entering Special Functions.
To use a special function, key in the corresponding code, then select SPCL.
Special Display.
To display the user-requested modes of special functions prefixed 1 through 10, select SPCL alone one time. The digit position (noted beneath the display) corresponds to the special function prefix, and the number displayed in that position corresponds to the special function suffix.
Special Special Display.
To determine the actual instrument settings corresponding to special functions prefixed 1 through
10, press the SPCL key alone once while the Special Display is active. (If the Special Display is not active, press the SPCL key twice to get this display.) The digit position corresponds to the special function prefix, and the number displayed in that digit corresponds to the special function suffix.
HP-IB PROGRAM CODES
All special fiinction codes are formed by the special function number followed by the code “SP”.
For example, the code for Special Function 7.3 is “7.3SP”.
For special function codes with zero as a suffix, force a single space if the zero is to be ommitted.
For example, “1O.OSP” could be “IO. SP”
EXAMPLES
Entering Special Functions.
To display the frequency of the signal in the IF (Special Function 34):
LOCAL
(keystrokes)
@@
(program codes) Code
34.0 SP
Function
3-272
Model 8902A
Viewing
When
the
Special Display.
SPCL is pressed alone once, the following display might result:
Operation
(=PREFIXES) r
5.0
-
6.1
7.2
8.8
9.2
10.0
Code
.o
2.1
3.0
4.2
Special Function
Name
RF Input Attenuation and Gain
Audio Ranae
RF and IF Filters
Tuned RF Level Detector Selection and Display Averaging
~
Audio Detector Response
Automatic Level Control
RF Frequency Resolution
Error Message Disable
IF Gain
RF Power Ranae
User-Requested Setting
Automatic Selection
radians dM
Automatic Selection (RF High-Pass Filter Out)
If Synchronous Detector with 1 Second
Averaging Time
Fast ResDonse
Fast Response
100 Hz
All Errors Enabled
dB IF Gain
Automatic Selection
Operation Model 8902A
1-
-1 u
5
U ! 5-
11
L O u 5-
I! jz[
11
U
/
(=SUFFIXES)
3-274
- - C F
~~
I
3.2
4-2
5.0
6.1
7.2
8.8
9.2
~~
Special Function
~
Name
I
1
RF Input Attenuation and Gain
Audio Ranae
RF and IF Filters
Tuned RF Level Detector Selection and Display Averaging
Audio Detector Response
Automatic Level Control
RF Frequency Resolution
Error Message Disable
~ ~~
IF Gain
10.1 RF Power Range
Actual Instrument Setting
10 dB Attenuation
_ _ _ _ _ _ ~
~
40% AM; 4 kHz FM; 4 radians qiM
~
1.5 MHz IF Frequency; 2.5 MHz IF Bandwidth;
Narrow Filter Out: RF High-Pass Filter Out
If Synchronous Detector with 1 Second
Averaging Time
100 Hz
All Errors Enabled
10 dB IF Gain
Range #1
COMMENTS
Omit Zero Suffixes.
If a special function has a suffix of zero, the zero need not be entered. For example, 10.0 SPCL
1O.SPCL. (However, 22.2 SPCL does not equal 22.20 SPCL nor does 18.1 SPCL equal 18.10 SPCL.)
If entering a special fiinction code evokes Error 21 (invalid key sequence), the special function requested has not been executed.
HP-IB.
Force a single space in “10. SP” if the zero is to be omitted.
CLEAR Key.
If an error is made while keying in the special function code, select CLEAR and re-enter the code.
Incongruity Between Special and Special Special Display.
In most cases, the user-selected special function suffix appears in both the Special Display and the Special Special Display. However, Special Functions 1.9 and 4.4 are user-selected, automatic- selection modes, and might display a different suffix in the Special Special Display.
I
Model 8902A Operation
DETAILED DESCRIPTIONS OF
ALL
SPECIAL FUNCTIONS
1. RF Input Attenuation and RF input attenuation or amplification to eliminate input overload or to improve measurement sensitivity. For more details about this function, refer to
Gain.
RF Inpirt
Use this special function
Arreniration and Gain to
select
1 .O Automatic selection
1.1 Attenuation of 0 dB
1.2 Attenuation of 10 dB
1.3 Attenuation of 20 dB
1.4 Attenuation of 30 dB
1.5 Attenuation of 40 dB
1.6 Attenuation of 50 dB
1.7 Gain of 24 dB
1.8 Gain of 14 dB (24 dB ga..i wit 10 dB attenuation)
1.9 Automatic selection with 10 dB attenuation always inserted (usually only used in Tuned
R F Level measurements)
2. Audio Range Selection. Use this special function to set the display resolution for modulation rncasurements. The Measuring Receiver’s display resolution is dependent on the modulation being measured and the detector being used. For example, in only display when the RMS
Hz in detail here. Refer
FM measurements, Special Function resolution when the deviation being measured to Airdio R m g c
1, is so less than 0.04 peak kHz and complex, it is not described for detailed tables for this function.
2.4 can
Special
Function
Code
3.0 SPCL
3.1 SPCL
3.2 SPCL
3.3 SPCL
3.4 SPCL
3.5 SPCL
3.6 SPCL
3.7 SPCL
3.8 SPCL a
IF
Frequency
3.0SP
3.1 SP 455 kHz
3.2SP
3.3SP
3.4SP
3.5SP
3.6SP
3.7SP
3.8SP
1.5 MHz
455 kHz
1.5 MHz
455 kHz
455 kHz
455 kHz
455 kHz
Wide
IF
Filter
Automatic Selection
Narrow IF
Filter
(30 kHz BW)
200 kHz BW
2.5 MHz
Low-Pass
200 kHz BW
2.5 MHz
Low-Pass
200 kHz BW
2.5 MHz
Low-Pass
200 kHz BW
2.5 MHz
Low-Pass
OUT
OUT
OUT
OUT
IN
IN
IN
IN
RF High-Pass
Filter
(5.25 MHz)
OUT
OUT
OUT
IN
IN
OUT
OUT
IN
IN
3-275
Operation Model 8902A
4. Tuned RF Level Synchronous and Average Detector and Display Averaging. Tuned R F level measurements can be made with one of two internal detectors: a narrow-band tracking synchronous detector or sensitive than the
(4.4
IF
IF a wider-band IF average detector. The average detector but the synchronous detector (4.0
Measurement dveraging time is automatically selected by the Measuring Receiver during the Tuned or 4.4 SPCL is selected. The Measuring Receiver chooses
4.0 Synchronous detector; averaging time is automatic.
4.1 Synchronous detector; averaging time is 10s.
4.2 Synchronous detector; averaging time is 1s.
4.3 Synchronous detector; averaging time is 0. Is.
4.4 Average detector; averaging time is automatic.
4.5 Average detector; averaging time is 10s.
4.6 Average detector; averaging time is Is.
4.7 Average detector; averaging time is 0.1s.
IF
IF synchronous detector is more
IF average detector is more tolerant of signal drift and residual FM than the average detector. When measuring noisy signals, use the 1F average detector
SPCL). The SPCL) is automatically selected on power-up.
RF Level measurement when 4.0 SPCL these times based on the requirements of its internal circuitry. However, experienced operators may want to increase or decrease the measurement time using Special Function 4.
5. Audio Detector Response. Use this special function to help stabilize measurements on unstable or noisy signals when making modulation or SIN AD measurements.'
5.0 Fast response time.
5.1 Slow response time.
6. Automatic Level Control. Use this special function to speed up the ALC response time or disable the ALC. (The faster ALC response time degrades AM accuracy at rates less than 1 kHz.)
Disabling the ALC, in conjunction with the rear-panel AM Output connector, can be used to measure
AM at very low modulation rates. Disabling the ALC also permits measurement in AM depth without regard to changes in carrier level. of to absolute changes
6.0 Slow ALC (for AM rates greater than 20 Hz).
6.1 Fast ALC (for AM rates greater than 1 kHz).
6.2 ALC off.
The slow response time for SlNAD date codc, select 42.0 SPCL.) is not availablc with firmware date codcs 234.1985 and below. (To display thc firmwarc
To ordcr a ROM sct that contains this spccial function. conlact the ncarest HP salcs office.
3-276
Model 8902A Operation
7. RF Frequency Resolution. Use this special fiinction to manually set the display resolution during frequency measurements (including RF, measurement time increases
.
7.0 Automatic selection.
IF, and LO frequencies). Note that with finer resolution,
7.1 Resolution of 10 Hz.
7.2 Resolution of 100 Hz. (When using an external selects 100 Hz resolution.)
LO value greater than 20 GHz. 7. I SPCL
7.3 Resolution of 1 kHz.
7.4 (Applies to R F Frequency measurements only; other measurements treat 7.4 as
Resolution of 0.1 from 10.1 MHz
Hz for input signals less than 10.1 through 1300 MHz.
MHz; resolution of measurement time with this resolution is approximately 20 seconds.)
1 Hz
(When measuring frequencies as high as for signals
1300
7.1.)
MHz,
8.Error Message Disable Control. Most combinations of Errors enabled to customize the behaviour of the instrument to
01 errors that are automatically disabled during each measurement. through 04 can be disabled or meet a particular set of measurement requirements. When the Measuring Receiver uses automatic selection of error messages, these messages are selectively enabled, depending on the measurement being made, to assure the broadest range of calibrated measurements. Error the
Mcssagc Disahk Confro/
on page 3-267 has a table that lists
8.0 Automatic selection of disabled error messages.
8.1 Disables Error 0 1.
8.2 Disables Errors 02 and 03.
8.3 Disables Errors 01,
8.4 Disables Error 04.
02, and 03.
8.5 Disables Errors 01 and 04.
8.6 Disables Errors 02, 03, and 04.
8.7 Disables Errors
Key, RANGE
01, 02,03, and 04. Performs the same function as DISABLE
OUTPUT
HOLD).
8.8 Enables Errors 01, 02, 03, and 04. This ensures that the output from MODULATION is safeguarded for most measurements. Some tuned, non-modulation measure- ment modes (such as frequency) do not completely safeguard the signal fidelity at this output since accurate demodulation is not the primary goal of that measurement mode.
9. IF Gain. Use this special function to insert gain into the Measuring Receiver's circuitry. The amplifier used has precise 10 dB gain steps ranging from for more information about this function.)
0 to 60 dB. (Refer to IF
9.0 Automatic Selection of gain for Tuned RF Level measurements.
9.1 Gain of 0 dB inserted.
9.2 Gain of 10 dB inserted.
9.3 Gain of 20 dB inserted.
9.4 Gain of 30 dB inserted.
9.5 Gain
9:'
40 dB inserted.
9.6 Gain of 50 dB inserted.
9.7 Gain of 60 dB inserted.
-
This special function is not available with firmwarc date codcs 234.1985 and below. (To display the firmwarc datc codc. sclcct
42.0 SPCL.) To ordcr a ROM sct that contains this special function. contact the ncarcst HP salcs oficc.
3-277
Opera tion Model 8902A
10. RF Power Range. Use this special function to manually select one of the five internal power ranges. In most applications, the Measuring Receiver will automatically select the appropriate power range. The following table lists the power ranges and their associated special function codes.
10.0 Automatic selection.
10.1 Range #1 (most sensitive range).
10.2 Range #2.
10.3 Range #3.
10.4 Range #4.
10.5 Range #5 (least sensitive range).
11.2. Previous Ratio. Use this special function to display the reference set with the RATIO key.
Use this special fiinction to compute an FM calibration factor for another RF signal analyzer that has no internal calibrator, or that has an internal calibrator that is to be cross checked. procedure for FM calibration, refer to FM Culihration
18 1 .)
(For a complete
12.0 Display the computed peak FM.
12.1 Display the demodulated peak residual FM.
12.2 Display the demodulated peak FM.
13. AM Calibration for Another Instrument in the HP 8902 and
Use this special function to compute an AM calibration factor no internal calibrator, or procedure for AM calibration, refer to AM Calihrafion for that has an internal calibrator that is to
8902 RF Signal Analyzer Family. another R F signal analyzer that has be cross checked.
(For a complete
13.0 Display the computed peak AM.
13.1 Display the demodulated peak residual AM.
13.2 Display the demodulated peak AM.
14. Measurement Limits. Use this special function in conjunction with the RATIO key to set lower and upper measurement limits.
Limit
(For a complete procedure
14.0 Clear limits; turn off LIMIT annunciator.
14.1 Set a lower limit to the Ratio reference. on setting measurement limits, refer to
14.2 Set an upper limit to the Ratio reference.
14.3 Restore the lower limit.
14.4 Restore the upper limit.
14.5 Display the lower limit.
14.6 Display the upper limit.
14.7 Display the code for the measurement the lower limit applies to.
14.8 Display the code for the measurement the upper limit applies to.
14.9 Display the limit status in the format “Lower.Upper” where O=disabled and l=enabled.
3-278
Model 8902A Operation
15. Time Base Check. Use this special function to check the status of the time base being used by
the Measuring Receiver. (More information about the time base is on page 3-3.)
15.0 Display whether the internal, Option 002 time base oven is warm enough source; 0 = warm. Error 12 is displayed if the time base is cold. to create a stable
15.1 Display whether the internal or external time base is being used; 0 = internal and
1 = external.
16. AM Calibration Factor. This special function enables you to disable, enable, or display the current AM calibration factor. Front-panel keys SAVE CAL (Blue Key, CALIBRATE) and % CAL
FACTOR (Blue Key, MHz) can also be used to enable and display the calibration factor. (For a complete procedure for AM calibration, refer to AM Calibration
16.0
16.1
16.2
Disable the AM calibration factor.
Enable the AM calibration factor.
Display the AM calibration factor. (Displays 0 if not enabled.)
17. FM Calibration Factor. This special fiinction enables current FM calibration factor. Front-panel keys SAVE CAL (Blue Key, CALIBRATE) and
FM
you
Calibration to disable, enable, or display the
Yo CAL
FACTOR (Blue Key, MHz) can also be used to enable and display the calibration factor. (For a complete procedure for FM calibration, refer to
17.0 Disable the FM calibration factor.
17.1
17.2
Enable the FM calibration factor.
Display the FM calibration factor. (Displays 0 if not enabled.)
18." Tone Burst Receiver.
A time delay of NN
Use this special function to measure the frequency of squelch tones. ms is inserted between detection of a carrier and unsquelching of the output at the MODULATION OUTPUT connector. The range of NN is 1 to 99 ms. If NN is 0, the delay is
99 ms. (Refer to Tone Birrst R m + w on
for more information about this function.)
21. HP-IB Address. Use this special function to display the HP-IB address in the form:
AAAAAAA.TLS., where:
AAAAAAA is the address in binary,
T = 1 = talk only,
L = 1 = listen only, and
S = 1 = requesting service.
22. Service Request. Use this special function to set up a service request mask. A value of NN from 0 to 63 sums the weighted conditions below to set up a service request mask. The summed, weighted conditions are displayed when NN is 64.
for more information about this service request mask.
1
2
4
Data ready
HP-IB error (cannot be disabled)
Instrument error
8 Limit exceeded
16
32
64
Frequency Offset mode state change
RECAL or UNCAL read back SRQ mask rev.ltiJUNE86 3-279
Operation Model 890214
23. External LO (Option 030 Only). Use this special function when making Selective Power
Measurements using an external LO. (Refer to information about this measurement.)
Selcjcfive Power Mcmirrtwwnrs
for more
23.0 Return the LO to internal.
23.1 Set the LO to external.
23.2 Display the status of the LO (O=Internal, L=External).
24. Selective Power Measurement (Option 030 Only). Use this special function when measurhg adjacent channel power or single-sideband noise. (Refer
for more information about this measurement.)
24.0
24.1 to Selecfive Powc*r Measirrcwwnls
Sets the Measuring Receiver to the Selective Power Measurement Mode.
Selects the wide-bandwidth IF filter for adjacent-channel or cellular radio power mea- surements; displays the IF level (in volts).
24.2
24.3
24.4
24.5
Establishes the level measured with 24.1 SPCL as the 0 dB reference.
Selects a narrower bandwidth IF filter than 24.1 SPCL for adjacent-channel power measurements; displays the IF level (in volts).
Establishes the level measured with 24.3 SPCL as the 0 dB reference.
Selects a very narrow bandwidth IF filter (2.5 kHz) for the single-sideband noise measurement; displays the IF level (in volts).
24.6
24.7
24.8
24.9
Establishes the level measured with 24.5 SPCL as the 0 dB reference.
Displays the noise measurement as normalized to a 1 Hz bandwidth.
Enables setting of the value of the noise measurement bandwidth.
Displays the value of the noise meawrement bandwidth.
25. Current Value of External Attenuation. Use this special function in conjunction with dB EXT
ATTEN (Blue Key, LOG/LIN) to scale level measurements to correctly indicate the power at the input of an external attenuator or amplifier connected to the Measuring Receiver. (For informatin on setting the value of external attenuation or gain, refer to Ex/ernal Alfcviiafion
25.2 Display the current offset in dB. (Amplification is shown as a
negative attenuation value.)
26. Relative Tuned RF Level Measurement. Use this special function in conjunction with SET
REF (Blue Key, ZERO) to make relative Tuned R F Level measurements. (Refer to Affenirafar
Measirrtwwnts on
for more information about this function.)
SET REF Enter the relative Tuned RF Level measurement mode and set the input signal level dB. as 0
26.0 Exit the relative Tuned RF Level measurement mode and enter the absolute Tuned R F
Level measurement mode.
26.1 Re-enter the relative measurement mode using the previous reference set with SET REF.
3-280
rcv.lciJUNE86
Model 8902A Operation
27. hequency Offset Control. converted input signals. (The Measuring Receiver can measure frequencies to 42 GHz when an external mixer and LO are used
Use this special function when making measurements on down- to down-convert the input signal. Refer to for requirements of the local oscillator and mixer.) The F'requency allows the Measuring Receiver to
Jkequency offset
Offset Control special function keep track of the frequencies involved in the down-conversion.
27.0 Exit the Frequency Offset Mode.
27.1 Enter the F'requency Offset Mode.
27.2 Display the external LO frequency.
27.3 Prepare of the to enter and enable the LO
40700
SPCL, enter the frequency
MHz can be entered.
29.0 SINAD Measurement. Use this special function to make SINAD (Signal to Noise And
Distortion) measurements on either internally demodulated signals or externally applied audio signals.
30.0 External Audio RMS Level Measurement. Use this special function level of an audio signal applied to the Measuring Receiver's AUDIO INPUT
rms
31. Tuned RF Level Noise Correction.
Detector (Special h c t i o n s
Function 31.1 is enabled, the normal h e d if
4.4 through noise correction is
Use
4.7) off this special function in conjunction with the when making Timed level signals. The selection of Special Function 31 is maintained through instrument power down (the
Measuring Receiver being turned off and then on).
The Timed RF Level measurement calibrates three low-level measurements. (The
RF
Then the HP 8902A measures the noise between the
RF
RF and display 1 if it is
RF input and the on.
Level measurements on low- input attenuation ranges
Level measurement procedure
RF
R E A L range, to is it
IF achieve accurate followed (that annunciator causes
Average is, the sensor
IF Average Detedor circuitry. is
In subsequent measurements (in this third range), the Measuring Receiver subtracts the measured noise from the total signal-plus-noise to display the measured signal level.
31.0 'Ihm off noise correction.
31.1 b
31.2 Display 0
Operating Information Pull-Out Curd illustrates these.) When Special stepping down in level and pressing the CALIBRATE key whenever the displayed). However, when the Measuring Receiver calibrates the third module to switch out the signal from the device-under-test momentarily (placing 5022 at the output).
This special function is not available with firmware
42.0 SPCL.) To order a ROM date codes 234.1985 and below. (To display the firmware date code, select set that contains this spec4 function, contact the nearest HP sales office. rev.25JUL87 3-281
Operation
COMMENTS ABOUT SPECIAL FUNCTION 31:
NOTE
Special finction 31.1 (for noise correction) should be entered once before making level measurements.
3i.o
SPCL.
To
clear Special finction 31.1 you MUST enter
Model 8902A
Special h c t i o n 31 can be especially useful when making measurements on down-converted signals.
Special h c t i o n s 31.0 and 31.1 can be toggled once the with 31.1 enabled. if Special h c t i o n
That and without the noise.
The Measuring Receiver
31.1
is,
the uses is signal a default
can
%ed
RF' Level calibration be measured alternately with the noise noise
Tuned
RF
Level calibration sequence. (The default noise value is the last value that was measured. This value is
Instrument Preset and power down.) has added been done the saved signal through
3-282
Do not use 31.1
SPCL
when making any uncalibrated, level measurement in Itcned
RF Level
mode
Sensor Module must be used when making Itcned calibrations with the AVG Detector. or relative without a power signal sensor. The
RF
Level range-to-range
32. dB and Frequency Resolution. measurements that use with resolution in 0.001 measurements, selection of Special h c t i o n 32.0 or 32.1
During is
RF Power and b e d
Receiver being
turned
simultaneously.)
32.0
32.1
32.2 off dB instead and then of on).
Hz
RF Level measurements, and to display the normally displayed resolution of to display
(Note that
0.1 resolution from
Special h c t i o n s 32.1
0.01
100 and
dB
to
32.9 measurements
During audio
250
can kHz.
The be enabled
Power is displayed with n o d measurement resolution of 0.01
Audio
250 is displayed with the dB. normal resolution of 1 Hz for frequencies from 100 to
Power is displayed with measurement resolution of 0.001 dB.
Audio frequency is displayed with a resolution of 0.1 Hz for frequencies from 100 to 250 kHz.
Displays 0 if the n o d finer resolution is enabled (32.1 SPCL). is enabled (32.0 SPCL) and displays 1 if a
32.9 making level measurements on low-level signals (greater than 40 to
Tuned RF Level Measurements Using Track-Mode Tuning.
drift.
The track mode tuning is available only with the through 4.7) which can measure levels be enabled simultaneously.) to -110
IF
MHz
Use this special function when into the HP that Special h c t i o n s
8902A)
32.1 that tend average detector (Special h c t i o n s and 32.9
4.4 can
To select track-mode tuning for a low-level 'Ibed RF' Level measurement: a. Instrument Preset the HP 8902A (blue key, green key). b. If external a down converter
L.O. to measure microwave frequency. Make sure that the L.O. signals, frequency results in an
HP
8902A of greater than 40
MHz
when mixed with the c. Set the RF signal to a level greater than -10 dBm. key in
RF
27.3 signal.
SPCL. Key in the
IF frequency to the reu.OlMAR88
Model 89028 Operation
Once d. e. Select f. Press the g. h. If using i. Step the signal level down
RECAL annunciator is displayed.
COMMENTS in amplitude and press the CALIBRATE key whenever the
SPECIAL FUNCTION 32.9:
If the signal appears to be lost, set the signal level of the device-under-test
Then select Blue Key, CLEAR (HP-IB code: BC). This key sequence forces a to greater than dBm. retune of the VCO during
RF
Allow
the HP 8902A to tune to the signal. (Wait for a frequency display.)
Select signal
32.9 has
MHz
an
ZERO key.
SPCL. (This
HP an absolute level measurement
ABOUT key
RF to
11722A is been recaptured, the same or HP step
11792A the as
Level (yellow shift key, signal entering enter the manual tune mode.
RF Power key). sensor module, press the CALIBRATE key or set a relative reference by pressing the blue key and the
Level measurements and should recapture the
4.4 signal
SPCL, if it has
8.1 not
SPCL, Log units, Track
drifted
at this point. more that to
5 make
MHz.
If the signal frequency into the HP 8902A drifts past one of the following frequency boundaries, the
Measuring Receiver will lose the signal and the measurement process must be restarted.
40
MHz,
80
MHz,
160
MHz,
320 MHz, and 640 MHz.
33.0 LO Frequency Measurement. signal being measured.
Use this special function to display the LO frequency for the
34.0 IF Frequency Measurement. Use this special function to display the IF frequency for the signal
MHz.
(Refer to
Filters, RF
and
IF
manually select the IF for frequencies above 10
35.0 RF Level Measurement. measurement is input. selected when RF POWER is selected and no to measure the power sensor is peak connected
RF
power. This
Tuned RF frequencies
RF Level Measurement.
Level Measurement. Use the Peak Tuned RF is not accurate or sensitive
Level measurement to the measure the level of that are drifting or to determine flatness as a function of carrier frequency. factors. An extensive table in of hquency Offset Mode (Special E'unction 27).
37.0 Use automatic calibration factors.
37.1 Use manual
RF
Use calibration factors. this special function
to manipulate
37.2 Display calibration factor status (O=automatic, l=manual).
RF Power calibration
used
is determined by the status
37.3 Enter calibration factor.
37.4 Display table size.
37.5 Prepare to recall the reference calibration factor.
37.6 Prepare to recd the next frequency/calibration factor pair.
37.9 Clear the table.
Two
rev.
01
MAR88
3-283
Operation Model 8902A
38.
39) in time
used
in Timed FW is decreased when it is not necessary
Use this special function
Level measurements. This function is useful to display calibration
(when used with Special h c t i o n to perform calibration. For more details about this function, refer to Timed RF Level
If the number of test frequencies is less than or equal to eight, consider using the storage registers to save the calibration data. For details about storing measurement settings, refer
Level measurements at many different frequencies. Measurement
(Note: to Store/Recall
To display and then re-use h e d RF Level calibration factors, perform calibration at the frequency of interest, read the calibration factors using Special h c t i o n 38, before making measurements at the previously measured frequency using Special b c t i o n 39.
38.1 Display the calibration factor for Range #l.
38.2 Display the calibration factor for Range #2.
38.3 Display the calibration factor for Range #3.
38.4 Display the SET REF reference calibration value. (This cal factor is displayed with a maximum of eight digits and a resolution of 0.01%) used in making repetitive Timed is to in
fined
RF
RP
Level
Level measurements. This function is it is
Level measurements
useful (when used with Special h c t i o n 38) at many different frequencies. Measurement time consider using the storage registers to save the calibration data. For details about storing instrument settings, refer to StorelRecall
To display and then re-use n n e d RF
Use this special function to enter calibration factors the number of test frequencies
Level calibration factors, is less than or equal to eight, perform calibration at the frequency of interest; read the calibration factors using Special Function 38; then re-enter the calibration factors before making measurements at the previously measured frequency using Special b c t i o n 39. (Before using Special F'unction 39, that the instrument is tuned to the input signal.)
39.1 Enter the calibration factor for Range #l.
39.2 Enter the calibration factor for Range #2.
39.3 Enter the calibration factor for Range #3.
39.4 Enter the SET REF reference calibration value.
39.9 Clear all calibration factors.
'
This special function
42.0 SPCL.)
SPCL.) is
ROM
ROM set
(To display the firmware that contains this special function, contact the nearest HP sales office. set that contains this special function, contact the nearest HP sales office. date code, select
This special function is not available with firmware date codes 234.1985 and below. (To display the firmware date code, select
42.0
To order a
To order a not available with firmware date codes 234.1985 and below.
3-284 rev.25JUL87
Model 8902A
Operation
ERROR MESSAGE SUMMARY
DESCRIPTION
Error Messages are one means the Measuring Receiver uses to safeguard measurement integrity.
When the instrument senses a potential error-causing situation, an Error Message code is displayed to alert the user of the condition. The Error Message code indexes an Error Message which describes the current error. Error Messages indicate operating problems, incorrect keyboard entries, or service- related problems. The error message is usually cleared when the error condition is removed,
Two types of error message display formats are used:
Error
- - No detectable signal falls within the IF passband. Either no signal is at the input, or the instrument cannot tune to find the applied signal. (For example, it might be manually tuned far enough away from an input signal that to the HP-IB as Error 96 no power is detected in the IF.) This display is output using the HP-IB output format described in “HP-IB Output Format”.
- - - -
A signal has been detected but, for various reasons, a measurement result is not yet available. The instrument might be still completing the measurement requested, or in some cases, unable to complete a measurement because of manual settings of special functions. (For example, when frequency measurements are made on a low-level input signal with high AM depth, or when the RF input attenuation or gain is improperly set.) This display is never output to the HP-IB and typically indicates a transitory state in instrument operation.
- - - - - -
The IF synchronous detector circuitry is searching for the IF signal. This error message can only be displayed when the
Level measurement mode. (Refer to Tuned
IF synchronous detector is used in the Tuned R F
RE‘ZJevel
This display is never output to the HP-IB and typically indicates a transitory state in instrument operation.
Error messages are grouped by error code as follows:
Errors 01 through 19 and 90 through 99.
These messages are Operating Errors which indicate a condition has not been met to assure a calibrated measurement. Operating controls (usually, the easiest way is key or Special Function 8
Errors to select AUTOMATIC OPERATION). The DISABLE ERROR can be used hfcssagc Disublc Conlrol
to can usually be cleared by readjustment of front-panel selectively disable Errors 01 through 04. (Refer to Error
3-285
Opera ti on Model 8902A
Errors 20 through 29.
These messages are Entry Errors which indicate an invalid or key sequence or keyboard entry. These function selection be made. Some of these error displays time out after a few seconds and then allow the display to return to the current measurement.
Errors 30 through 39.
These met to are Tuned RF Level Calibration Errors which indicate a condition that has not been assure calibration. The error can usually be cleared by readjusting the input signal, setting Special Functions 1 and 9 to automatic selection. or by
Errors 40 through 89.
These messages are Service Errors generated to provide service-related information. They must be enabled to be displayed since they are not displayed in normal instrument operation. Service
Messages are discussed in Section 8 of the Service Manual.
Error
HP-IB
HP-16
The
Output Format
HP-IB
Fixed Data
+900000 DD 00 E+01 CR LF
Error Cod
Fixed Data
Line Feed
Carriage Return
Fixed Exponent
For example, Error 02 is output to the HP-IB as +9000000200E+O1CRLF. Once an error has been input to the computing controller, the error code is simply derived by subtracting input number, then dividing the result by 1000.
9x 10'" from the
Error Messages
The following table describes all Operating Errors and includes the error code, message, and the action typically required to remove the error-causing condition. The COMMENTS column that follows provides additional information and references pertaining to particular error messages.
3-286
Model 8902A Operation
13
14
15
16
17
09
10
11
12
18
19
96
Error
Code
05
06
07
08
01
02
03
04
Message
IF frequency error.
Input level too high.
Input Level too low.
Audio circuits overdriven.
FM spuelched.
RF input overload.
Voltmeter and display overload.
Calibrator error.
Option not installed.
Input frequency out of range.
Calculated value out of range.
Time Base oven cold (Option 002).
Power sensor not connected.
Power sensor cannot zero.
Calibration factor error.
Audio circuits underdriven.
Selective power measurement (option series 030)
RF Power will not calibrate.
Tuned RF Level circuits underdriven.
(HP-IB only) No input signal sensed by instrument.
)perating Errors
Corrective Action
Retune to signal at input.
Increase RF input attenuation.
Decrease RF input attenuation.
Increase audio range.
Reduce signal level varations (AM) at RF INPUT.
Reduce RF signal level at RF INPUT, then press any key.
Increase audio range.
Connect CALIBRATION AM/FM OUTPUT to RF INPUT or turn off calibrator.
Select another instrument function.
Adjust input frequency to within specified limits.
Conversion from
O/o to dB is not possible. Press LOG/LIN for linear display.
For highest accuracy, wait until oven is warm. (Refer to Special
Function 15.)
Press RF POWER. RF level measurement is initiated if the power sensor is not connected.
Assure zero power at SENSOR input.
Input calibration factors.
Increase external audio input level.
Release RANGE HOLD, adjust input level or re-reference measurement.
Assure 0 dBm at SENSOR input.
Press Automatic Operation.
Increase signal level at RF INPUT or retune.
COMMENTS
Error 01
With the 1.5
MHz
With the 455 kHz IF, the IF frequency must be 1.5 MHz f50 kHz. the IF frequency must be 455 kHz h2.5 W z . kHz Tuned RP level.)
Refer to RF Frequency Tuning. Error 01 disables MODULATION OUTPUT/AUDIO INPUT.
Error 02
Refer to RF Input Attenuation and Gain
OUTPUT/AUDIO INPUT. for nominal input levels. Error 02 disables MODULATION
Error 03
Refer to RF Input Attenuation and Gain for nominal input levels. Error 03 disables MODULATION
OUTPUT/AUDIO INPUT. rev. 15JUN90 3-287
Opera tion Model 8902A
Error 06
Maximum allowable input level is 7 Vrms (1 W peak).
Error 07
If displayed during modulation measurements, increase audio range. If displayed during level measurements, increase RF input attenuation or increase RF power range.
Error 08
.;
1
If the connection from CALIBRATION AM/FM OUTPUT to indicate calibrator malfunction.
RF INPUT intact, this error may
Error 09
Error 09 display times out. If the option is installed, Error 09 displayed may indicate an option malfunction.
Error 10
Error 10 turns off MODULATION OUTPUT/AUDIO INPUT.
Error 11
In dB RATIO, Error 11 is displayed when measurement result is 0 or negative. (The argument of the log function must be greater than 0.)
Error 12
Error 12 is enabled by Special Function 15.
Error 13
Error 13 usually only occurs when the power sensor is disconnected during an RF power measurement.
Error 14
Error 14 will not occur when using a sensor module (such as the HP 11722A) or a power sensor with an RF switch controlled by voltages accessed from the rear panel. (Refer to Rcmolc Control R F
Swilch
Error 15
Rerer to RI: Powcr
for entry and edit information concerning calibration factors.
Error 17
Several conditions can cause this error:
0
IF level too high for available range. Either Range Hold was selected or one of the measurement ranges (Special Functions 1 through and try the measurement again.
10) was user selected. Select AUTOMATIC OPERATION
0
0
IF level too low when making a reference measurement. The reference is below 1.25V. Increase the source level to between 1.25V and 2.5V.
Either a ratio measurement was attempted with an inadequate reference measurement reference was not measured before the ratio measurement was attempted. Take measurement with the reference level between 1.25V and 2.5V. or the a reference
3-288
Model 8902A Ope rat ion
Errors
20
21
22
23
24
25
26
Error 96
Error 96 corresponds to a display of two dashes (- -). Error 96 can occur when no signal is applied or when Error 03 is disabled and the instrument is manually
96 (- -) turns off MODULATION OUTPUT/AUDIO INPUT. tuned where no signal is found. Error
Entry Err
Message
Entered value out of range.
Invalid key sequence.
Invalid Special Function prefix.
Invalid Special Function suffix.
Invalid HP-IB code.
Special Functions selected not compatible with selected measurement.
End of RF POWER calibration factor table reached.
B
~~ ~ Corrective Action
Re-enter new value.
Check for compatibility of functions selected
Re-enter correct Special Function Code.
Re-enter correct Special Function Code.
Re-enter correct HP-IB code.
Press AUTOMATIC OPERATION
Check number of entries.
Error 20
When this error occurs during single-sideband noise measurements, the bandwidth entry was out- of-range. Usually it is unnecessary to enter a bandwidth for noise measurements. This bandwidth is established at the factory.
Errors
30
31
32
33
34
35
Message Corrective Action
Manual input attenuation or gain selection. Change RF input attenuation and gain.
Requires new power reference.
Calibration not possible.
Power sensor reference error.
Signal lost during calibration.
Level error during calibration.
Calibrate RF Power before attempting calibration of
Tuned RF Level.
Move input Signal level into avalid calibration range.
Maintain consistency in frequency and level at SENSOR during calibration.
Maintain frequency stability at RF INPUT during calibration.
Maintain signal stability at RF INPUT during calibration.
I
Errors
40-89
I I
Messaae
Serivce-related errors.
Errors 40 through 89
Service errors are normally disabled.
Entry Errors
I
I Corrective Action
Refer to service section of HP 8902A instrument manual. rev.24OCT86
Performance Testa Model 8902A
Table of Contents
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance Test 4-Audio Filters
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance Test 6-Power Reference (Using Reference Comparison)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance Test 1 4 - k e d RF Level
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Abbreviated Performance Testing
7-Power Reference (Using DC Substitution)
Level (Using a Step Attenuator)
Performance Test 12-High-Selectivity Filters (Options 032 and 033)
. . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . .
4-0 rev.01 FEB89
Model 8902A Performance Tests
Section 4
PERFORMANCE TESTS
4-1. INTRODUCTION
The procedures in this section test the instrument’s electrical performance using the specifications
of Table 1-1 as performance standards. All tests are performed without accessing the interior of
the instrument. A simpler operational test is available in Section 3, Opcralion, under the title Basic
Firncfional Chccks.
NOTE
Uttlcss 0fltc.rwi.w nofed,
no
warm-up pcriod is rtyiiircid Jor thc~Jollowing
Linc voltagc mirst be within +590 and -1090 of nominal f the rcw1t.r oj’thc ptJrjormantu
tmfs
arc
io
he considcwd valid.
4-2. EQUIPMENT REQUIRED
Equipment required for the performance tests is listed in Table 1-3, Rccomrncwdcw’ TcYt Eqniprntwt.
Any equipment that satisfies the critical specifications provided in the table may be substituted for the recommended model(s).
4-3. PERFORMANCE TEST RECORD
Results of the performance tests may be procedures. The Ptv$orrnance Tesf Record
-Abula lists ed on the Ptyfbrrnuntu Test Rucord at the end of the all of the tested specifications and their acceptable limits. The results, recorded at incoming inspection, can be used for comparison in periodic maintenance and troubleshooting and after repairs or adjustments.
4-4. CALIBRATION CYCLE
This instrument requires periodic verification of performance. Depending on the use and environ- mental conditions, the instrument should be checked using the following performance tests at least once every year.
4-5.
ABBREVIATED PERFORMANCE TESTING
No abbreviation of performance testing is recommended.
4- 1
Performance
Tests Model 8902A
Specification
I
Characteristic
AMPLITUDE MODULATION
Rates
Performance
Test 1-AM
Performance Limits
Depth
Accuracy( 1*293*4)
Flatness '*')
Demodulated Output
Distortion
Residual AM
20 Hz to 100 kHz
To 99%
&?O/O of reading il digit i3% of reading il digit il% of reading il digit f3% of reading fl digit
M.3% of reading fl digit
<0.3% THD
<O.6% THD
<0.01% rrns
Conditions
to 1300 MHz carrier
to
99% depth
20 Hz to 10 kHz rates; to 99% depth
to 1300 MHz carrier;
99% depth
1300 MHz carrier;
99% depth
90 Hz to 10 kHz rates; 20 to 80% depth
4 0 % depth
<95% depth
FREQUENCY MODULATION
AM Rejection(2) <20 Hz peak deviation
I
PHASE MODULATION
50% AM depth;
rates;
AM Rejection(2)
( l ) But not to exceed 50 kHz rates with rms detector.
('1 Peak residuals must be accounted for in peak readings. (Refer to Residual Noise Effects in Detailed
(3)
( 4 )
(')
Operating lnstrucfions in Section 3.)
For peak measurements only, AM accuracy may be affected by distortion generated by the Measuring
Receiver. In the worst case, this can decrease accuracy by 0.1% of reading for each 0.1%
For rrns detector, add 33% of reading.
Flatness is the variation in indicated AM depth for constant depth on input signal.
For optimum flatness, cables should be terminated with their characteristic impedance. of distortion.
Model 8902A Performance Tests
Description
AM accuracy at a 10 kHz rate. A low-residual AM source is connected to the input and the internal residual AM is measured. A source, which can produce wide-band, linear AM, is modulated at various AM rates and depths to measure distortion, flatness, and incidental FM and QM. A special AM/FM test source is required for is measured with the internal AM Calibrator, which produces approximately 33% AM these tests to assure that the AM source has adequate bandwidth, low distortion, low residual AM, and low incidental FM and cPM.
Equipment
AM/FM Test Source
Audio Analyzer..
................................................................
Audio Synthesizer..
11715A
HP 8903B
HP 3336C
0 zzz;;
000000 0000
0
0 0
,"
#:
INPUT
(Step 10) INPUT
J
(stoL!!.m- AM OUTPUT
ANALYZER OUTPUT
(stop 7 )
I
.--.
(Stop 14)
Figure 4-1. A
M
Perfiirmancc Test Setiip
NOTE
In
[he following proccditrt2 rhc RI: moditlation soitrce can he conncx*tcd tither
to
a sensor moditk (which is conncc(cd to (hc Mcasiiring Rcccivtir) or dircwly to [he Measiiring Rectivcv-3 INPUT connector. The proccdiirc is writlcn Jbr
(he lntler case.
Procedure
AM Accuracy at 10 kHz Rate
1. On the Measuring Receiver, press the blue key then press INSTR PRESET (the AUTOMATIC
OPERATION key) to preset the instrument. Connect the Measuring Receiver's CALIBRATION
AM/FM OUTPUT to its INPUT.
NOTE
For
greatcst
occ-irrucy,
ullow the Mtwsirring Rtwiwr to
worm
itp
.for at
least one-half' hour.
4-3
Performance Tests Model 8902A
2. On the Measuring Receiver, press AM and then press CALIBRATE. Allow at least two readings
(approximately 40 seconds) to pass. The display should read between 99 and 101Yo.
AM Calibration Factor 40Yo AM Range: 99 101%
3. Key in 2.2 SPCL to set the AM range to 100% AM. Allow at least two readings to pass. The display should read between 99 and 101%. Record this value for future reference.
AM Calibration Factor 100% AM Range: 99 101Yo
Residual AM
4. On the AM/FM test source, set the t.est mode switch
output to the Measuring Receiver’s INPUT. (See Figure 4-1.
Nothing should be connected to the test source’s audio input.) to AM. Connect the test source AM
5.
6.
On the Measuring Receiver, press FREQ and TRACK MODE. Tune the AM/FM test source’s carrier frequency to approximately 12.5 MHz. Press TRACK MODE again to turn it off.
On the Measuring Receiver, press AM. Key in 2.0 SPCL to set the modulation range to auto- matic. Set the other controls as follows:
HP FILTER
LP FILTER
DETECTOR
....................................................................
....................................................................
50
3
Hz kHz
AVG
The display should show 0.01% or less.
Residual AM: 0.010/0
AM Distortion
7. Set the audio analyzer’s oscillator to 20 kHz. Connect its output to the audio input of the
AM/FM test source. (See Figure 4-1.)
NOTE
For
this t w , thc high inpiit
if
the
low connector
airdio a n a l p r shoiild or high oirtpirt bz ha.s jlonting inpirt groirnhd.
connwior.
Connections und oirfpiit shoirld bc connectors,
mndc
to thc
8. Set the Measuring Receiver controls as follows:
HP FlLTER
LP FILTER
DETECTOR
................................................................
.................................................................
.ALL
.ALL
OFF
OFF
PEAK+
9. Adjust the audio analyzer’s oscillator level for a Measuring Receiver display of 500/0
4-4
Model 8902A Performance Tests
IO. Connect the audio analyzer’s input to the Measuring Receiver’s MODULATION OUTPUT/
AUDIO INPUT. (See Figure 4-1.)
Set the audio analyzer to measure the distortion on the 20 kHz signal at the MODULATION OUTPUT/AUDIO INPUT with 80 kHz of low-pass filtering
(on the audio analyzer). The distortion should be 0.3% or less (-50 dB or less).
11.
AM Distortion at 20 kHz Rate; 5oVo AM: 0.3%
Increase the audio analyzer’s oscillator level until the Measuring Receiver reads 95% AM. Mea- sure the distortion. The distortion should be 0.6% or less (-44 dB or less).
12.
AM Distortion at 20 kHz Rate; 95% AM: 0.6%
Set the audio analyzer’s oscillator frequency to 20 Hz. Readjust the level, if necessary, for a
Measuring Receiver display of 95% AM. Measure the distortion. The distortion should be 0.6% or less.
AM Distortion at 20 Hz Rate; 95% AM: 0.6%
13. Decrease the audio analyzer’s oscillator level until the Measuring Receiver reads
Measure the distortion. The distortion should be 0.30/0 less.
50% AM.
AM Distortion at 20 Hz Rate; 50% AM: 0.3%
AM
Flatness
14. Set the audio synthesizer to 1 kHz
Receiver display of 80Yv AM. at + I dBm. Connect its output to the audio input of the
AM/FM test source. (See Figure 4-1.)
Fine adjust the audio synthesizer level for a Measuring
NOTE
Flatncm of the audio synthcsizt>r is criticaljor this test. If‘the audio synthesizer has liwling capability, switch it on.
15. On the Measuring Receiver, press AVG. Set RATIO on (with LOG/LIN set for a linear display).
Set the audio synthesizer frequency as listed in the following table. For each setting, note the
Measuring Receiver’s display. The difference in readings between any be less than 0.8% REL. two frequencies should
Audio Synthesizer
Frequency (Hz)
1 000
10 000
150
90
Displayed AM
(Yo REL)
AM Flatness (Maximum Difference): 0.8Y0 REL
4-5
Performance
Testa
Model 8902A
AM Accuracy
17. the audio detector time constant
Set to the audio synthesizer frequency close possible to 80.0% slow. to to turn it off. Press PEAK+. Key in 5.1 SPCL to set kHz. Set the audio synthesizer level for a display as on the Measuring Receiver. Record the display reading below.
40.0% reading: % A M
18. On the Measuring Receiver, key in the reading recorded in step factor recorded in step 3 then press RATIO. For example, step 3 is 100. 4% and the reading from then press the RATIO key. step 17 is if
80.15%, the divided
AM the AM calibration
Calibration Factor you would key in 79.83 (that is ,
Audio
Synthesizer hequency(Hz)
50 000
100 OOO
50
20
AM Limits (% REL)
Lower Actual Upper
98.9
96.9
98.9
96.9
-
101.1
103.1
NOTE ztl digit at a nominal reading of 80.0 is about icO.195 of the reading in the
RATIO mode.
4-6
Audio
Synthesizer m u e n c y ( ~ z )
20
50
10 000
AM Limits (% REL)
Lower
96.9
97.9
97.9
-
102.1
102.1
AM Rejection
LP FILTER to 3 kHz. off. Set the HP FILTER
21. Set the audio synthesizer frequency to 1 kHz. Set its level for a Measuring Receiver display of
22.
50% AM.
On the Measuring Receiver, press FM. Momentarily disconnect the audio input to the AM/FM test source and note the residual FM displayed on the Measuring Receiver. to 50 Hz and the
Residual F M 455 kHz I F Hz
23. Reconnect the audio input of the AM/FM test source. or less.
Note the Measuring Receiver's displayed
FM. The displayed FM minus one-half the residual FM noted in step 22 should be 20 Hz peak
AM Rejection (with FM); 455 kHz I F 20 Hz rev.15DEC88
Model 8902A Performance Tests
24. On the Measuring Receiver, key in 3.0 and 23.
SPCL to set the IF back to 1.5 MHz. Repeat steps 22
AM
Residual FM; 1.5 MHz
Rejection (with FM); 1.5 MHz IF 20
25. On the Measuring Receiver, press QM. Momentarily disconnect the audio input test source and note the residual QM to the AM/FM
Residual MHz I F rad
26. Reconnect the audio input peak or less. of the AM/FM test source. Note the Measuring Receiver’s displayed
QM. The displayed QM minus one-half the residual QM noted in step 25 should be 0.030 rad
AM Rejection (with QM); 1.5 MHz IF: 0.030 rad
4-7
Performance Tests Model 8902A
Specification
Characteristic
FREQUENCY MODULATION
Rates(')
Performance
Test 2-FM
Performance Limits
Demodulated Output
Conditions
kHz
20 Hz to 200 kHz
20 Hz to 20 kHz
40 kHz peak maximum
400 kHz peak maximum
40 kHz peak maximum e% fl digit fl
O/O of reading fl digit f5% of reading fl digit
<0.1% THD
THD
<8 Hz rms at 1300 MHz decreasing linearly with frequency to <1 Hz rms for 100 MHz and below
to 1300 MHz carrier
to 1300 MHz carrier;
750 ps de-emphasis
MHz carrier
to 1300 MHz carrier
to 1300 MHz carrier;
750 ps de-emphasis
250
kHz rates;
<40 kHz peak deviation
to 1300 MHz carrier;
50 Hz to 100 kHz rates;
<400 kHz peak deviation;
<40 kHz peak deviation with 750 p.s de-emphasis
to 1300 MHz carrier;
20 Hz to 200 kHz rates;
<400 kHz deviation;
<40 kHz peak deviation with 750 ps de-emphasis
MHz carrier;
<lo kHt peak deviation
to 1300 MHz carrier;
20 Hz to 100 kHz rates;
<1 kHz peak deviation;
<40 kHz peak deviation with 750 ps de-emphasis
kHz bandwidth
( 2 )
( 4 )
( 5 )
But not
With to
(3) For rms detector, add
750 exceed 50 kHz rates with rms detector.
Peak residuals must be accounted for in peak readings. (Refer to Residual Noise Effects in Derailed
Operating instructions in Section 3.)
ps f3% of reading. de-emphasis and pre-display "off", distortion is not specified for modulation outputs peak. This can occur near maximum deviation for a measurement range at rates
But not to exceed 20 kHz rates and 40 kHz peak deviation with 750 kHz.
,us de-emphasis.
>4V
Model 8902A Performance Tests
*
Characteristic Performance Limits Conditions
AMPLITUDE MODULATION
FM Rejection(2)
~
I <0.2% AM
<0.2% AM
250 kHz to 10 MHz carrier;
<5 kHz peak deviation;
400 and 1000 Hz rates;
50 Hz to 3 kHz bandwidth
10 to 1300 MHz carrier;
<50 kHz peak deviation;
400 Hz and 1 kHz rates;
50 Hz to 3 kHz bandwidth
(2)
I I
Peak residuals must be accounted for in peak readings. (Refer to Residual Noise Effects in Detailed
Operating Instructions in Section 3.)
Description
FM is measured with a very low-noise oscillator at the Measuring Receiver’s input. The resulting measured FM is the residual FM of the Measuring Receiver’s internal local oscillator. FM accuracy is measured with the internal FM Calibrator, which produces approximately 34 kHz peak deviation at a 10 kHz rate. A source, which can produce wide-band, linear FM, is modulated at various FM rates and deviations to measure distortion, flatness, and incidental AM. A special AM/FM test source is required for these tests to assure that the FM source has adequate bandwidth, low distortion, low residual FM, and low incidental AM.
Equipment
AM/FM Test Source
Audio Analyzer..
Audio Synthesizer
............................................................
HP
HP
11
HP
715A
89038
3336C
CAI
HP 8902A
0
:g::
000000 0000 0
0
0 0
0 0000
0
AUDlO INPUT gggg
0 (Stap 15) INPUT
1
1
(Step 31
.
LOW RESIDUAL OUTPUT
FM+4 OUTPUT
AUDIO ANALYZER
I
OUTPUT
( S t e p s 7.30)
7
I
OUTPUT
4-9
Performance Tests Model 8902A
NOTE to a followiiig procedirrc thcs RF modulation soiircc can hc conncctcd cithcr smsor module (which is connected
to
thtj Mtjasiiring Rmiver)
or
dirwtly to (he Measiiring Rtwivw's the latter
case.
INPUT
connector. The proccdirre is writlcw ./or
Procedure
Residual FM
1. On the AM/FM test source, set the test mode to residual FM. Connect
MHz) output to the Measuring Receiver's INPUT. (See Figure 4-2.) its low-residual (560
2. On the Measuring Receiver, press the blue key then press INSTR PRESET (the AUTOMATIC
OPERATION key) to preset the instrument. Set the other controls as follows:
MEASUREMENT
HP FILTER..
LP FILTER
DETECTOR
................................................................
50
3
FM kHz
AVG
The display should read 4 Hz or less.
Residual FM at 560 MHz; 50 Hz to 3 kHz bandwidth: 4 Hz
NOTE
Thc cqiration for dctcrmining the rcsidiral FM limits is: rcsidiral I:M in Hz = 5.83 x carrier.f~~jqircncy GHz + 0.42 Hz.
For
a
carrim ~1.560 digit of irncwtainty giws
is
3.7 Hz. Allowing./or onc a limil of approximakly 4
Hz.
FM Accuracy at 10 kHz
Rate
3. Connect the Measuring Receiver's CALIBRATE AM/FM OUTPUT to the INPUT. (See Figure
4-2.)
NOTE
For grt~afc~f lo warm iip jbr af lwst onr-halj' hoirr.
4. On the Measuring Receiver, press CALIBRATE. Allow at least two readings (approximately 40 seconds) to pass. The display should read between 99 and 1010/0. Record this value for fiiture reference.
FM Calibration Factor; 40 kHz Modulation Range: 99 1010/0
4-10
Model 8902A Performance Tests
5. On the Measuring Receiver, key in 2.3 SPCL to set the modulation range to 400 kHz. Allow at least two readings to pass. The display should read between 99 and 101%.
FM Calibration Factor; 400 kHz Modulation Range: 99 101%
6. On the AM/FM test source, set the test mode to FM. Connect its F M i 4 output to the Measuring
Receiver’s INPUT. (See Figure 4-2.)
7. Set the audio analyzer’s oscillator to 10 kHz at 1V. Connect its output to the audio input of the
AM/FM test source. (See Figure 4-2.)
NOTE
For [his test, [fthc audio analyzer has jloating inpirt and oirtpirt conncWws,
{he low high inpill
or
high sltoiild hc~ groirndcd. Conncciions shoirld bc madc oiilpirf connccfor.
to
the
8. On the Measuring Receiver, press FREQ and TRACK MODE. Tune the AM/FM test source’s carrier frequency to approximately 100 MHz. Press TRACK MODE again to turn it off.
9. On the Measuring Receiver, press FM. Set LP FILTER to 15 kHz and DETECTOR to AVG.
Key in 2.0 SPCL to set the modulation range to automatic.
10. Adjust the audio analyzer’s oscillator level for a Measuring Receiver display of 20 kHz average deviation. On the Measuring Receiver, set RAT10 on (with LOG/LIN set for a linear display).
11. Connect the FMi-32 output of the AM/FM test source to the Measuring Receiver’s INPUT without disturbing the AM/FM test source’s controls. (See Figure 4-2.) Multiply the displayed ratio on the Measuring Receiver by the calibration factor of step 4. (For example, if the display reads 12.529’0 REL and the calibration factor of step 4 is 100.4%, the result is 12.52 x 100.4 =
12.57% REL.) The result should be between 12.35 and 12.65Yo REL.
FM Accuracy; 4 kHz Modulation Range: 12.35 12.65% REL
FM Distortion, Accuracy, and Rejection--1.5 MHz IF
12. Connect the F M i 4 output of the AM/FM test source to the Measuring Receiver’s INPUT.
(See Figure 4-2.)
13. On the Measuring Receiver, set all LP FILTERS to off, DETECTOR to PEAK+, and RATIO
Off.
14. Set the audio analyzer’s oscillator frequency to 100 kHz. Set the level for a Measuring Receiver display of 100 kHz peak deviation.
15. Connect the audio analyzer’s input to the Measuring Receiver’s MODU LATlON OUTPUT/
AUDIO INPUT. (See Figure 4-2.) Set the aiidio analyzer to measure the distortion on the 100 kHz signal at the MODULATION OUTPUT/AUDlO INPUT (all audio analyzer filters should be off). The distortion should be O.lo/o or less (-60 dB or less).
FM Distortion at 100 kHz Rate; 100 kHz Peak Deviation: 0. 1%
4-1 1
Performance Tests Model 8902A
16. Set the audio synthesizer to 10 kHz at +5 dBm. Connect its output to the audio input of the
AM/FM test source. (See Figure 4-2.) Fine adjust the level for
100 kHz times the calibration factor of step 5. a Measuring Receiver display of
(For example, if the calibration factor is 100.4%, set the level for a display of 100.4 kHz.) of step 5
NOTE
Flatness of the airdio synthesizer is critical for this test. has Itwling capability, swirch it on.
If
the airdio synthesizer
17. Set the audio synthesizer to the frequencies in the following table. For each setting, the Mea- suring Receiver’s display should read between the limits indicated in the table.
Audio
Synthesizer
Frequency
50 000
100 000
50
20
(Hz) Lower
98.9
94.9
98.9
94.9
FM Limits (kHz)
Actual Upper
-
-
101.1
105.1
18. On the Measuring Receiver, set HP FILTER to 50 Hz and LP FILTER to 3 kHz.
19. Set the audio synthesizer frequency to 1 kHz. Set the level for a Measuring Receiver display of
50 kHz peak deviation.
20. On the Measuring Receiver, press AM. Momentarily disconnect the audio input to the AM/FM test source and note the residual AM displayed on the Measuring Receiver.
Residual AM:
90
21. Reconnect the audio input of the AM/FM test source. Note the AM displayed on the Measuring
Receiver. The displayed AM minus one-half the residual AM noted in step or less.
20 should be 0.2%
FM Rejection at 1 kHz Rate; 50 kHz Peak Deviation: 0.2%
FM Distortion, Accuracy, and Rejection-455 kHz IF
22. Connect the FM+32 output of the AM/FM test source to the Measuring Receiver’s INPUT.
(See Figure 4-2.)
23. On the Measuring Receiver, key in 3.1 SPCL to set the IF to 455 kHz. Press FM.
24. Set the audio synthesizer level for a Measuring Receiver display of 5 kHz peak deviation.
25. On the Measuring Receiver, press AM. Momentarily disconnect the audio input to the AM/FM test source and note the residual AM displayed on the Measuring Receiver.
Residual AM:
010
26. Reconnect the audio input of the AM/FM test source. Note the AM displayed on the Measuring
Receiver. The displayed or less.
AM minus one-half the residual AM noted in step 25 should be 0.2%
FM Rejection at 1 kHz Rate; 5 kHz Peak Deviation: 0.2%
27. On the Measuring Receiver, press FM. Set all HP FILTERS to off and LP FlLTER to >20 kHz.
4-12
Model 8902A Performance
Tests
28. Set the audio synthesizer level for a Measuring Receiver display of 10 kHz peak deviation times the calibration factor of step the level for a display of
(For example, if the calibration factor of step 4 is 100.4Y0, set
10.04 kHz.)
29. Set the audio synthesizer
to
the frequencies shown in the following table. For each setting, the
Measuring Receiver’s display should read between the limits indicated in the table.
I ~
1 0 000
20
I
I
9.79
9.79
I
I
___
___
I
I
10.21
10.21
I
30. Set the audio analyzer’s oscillator to 10 kHz at Connect its output
AM/FM test source. (See Figure 4-2.) Fine adjust the oscillator level for a Measuring Receiver display of 10 kHz peak deviation.
4V. to the audio input of the
31. Set the audio analyzer to measure the distortion on the 10 kHz signal at the MODULATION
OUTPUT/AUDIO lNPUT of the Measuring Receiver. Set the distortion analyzer’s low-pass filter to dB or
30 less). kHz and the high-pass filter to 400 Hz. The distortion should be less than 0.1% (-60
FM Distortion at 10 kHz; 10 kHz Peak Deviation: 0.1%
4- 13
Performance Tests Model 8902A
Performance Test 3-@M
Specification
Performance Limits Condltions Characteristic
PHASE MODULATION
Rates 200 Hz to 10 kHr
200 Hz to 20 kHz
150 kHt to 10 MHz carrier
10 to 1300 MHz carrier
Accuracy( lV2)
39% of reading il digit f3% of reading il digit
150 kHz to 10 MHz carrier
10 to 1300 MHz carrier
Demodulated Output
Distortion
I
400
<0.1% THD
0.1 Radian
1
, /
1 50 kHzSf,<lO MHz
9
40
20
E
10
,$
4.0
=
2.0
1.0 m .4 n. .2
100 200
/
400 ms detector only l k 2k 4k 10k
Modulation Rate (Hz)
20k
Phase Modulation Deviation and Maximum Resolution
(I) Peak residuals must be accounted for in peak readings. (Refer to Residual Noise Effects in Detailed
( 2 )
Operating Instructions in Section 3.)
For rms detector, add f3% of reading.
Description
A signal with a known amount at a known peak deviation (as of phase modulation is generated by frequency modulating a carrier measured by the previously-calibrated Measuring Receiver) and rate.
The relationship between the peak phase deviation and peak frequency deviation is: peak phase deviation = peak frequency deviation modulation rate
The measured deviation is compared with the calculated deviation for several combinations of FM deviation and rate. The distortion these tests to assure that the
FM.
FM is also measured. A special AM/FM test source is required for source has adequate bandwidth, low-distortion, and low residual
4-14
Model
8902A Performance Tests
EQUIPMENT
AM/FM
Audio
...................................................................
Audio Synthesizer.
HP
8903B
0
F
::".:
0 0
-
28888
0
0
I
INPUT
(Step 12) INPUT
STEP 6
,
AUD IO ANALYZER
AWFM
TEST SOURCE
8
':: FW32 OUTPUT
(Step
yzpp,":
7)
0 0 0 0 0
OUTPUT
~~ ~
Figure
4-3. QM Performance Test Setup
AUDIO SYNTHESIZER
DUTPUT
-
(Step 3)
NOTE
In the following procedure the
RF
either to a sensor module (which is modulation source can be connected connected to the Measuring Receiver) or directly to the Measuring Receiver's INPUT connector. is written for the latter case.
The
procedure
PROCEDURE
oM Accuracy
1. Perform Performance Test
Receiver's
2-FM.
2. On the AM/FM test source, set the test mode to FM. Connect its FM output
3. Set the audio synthesizer to 200 Hz at -10
dBm.
Connect its output to the Measuring to the audio input of the
4.
5.
INPUT.
AM/FM
test source. (See Figure 4-3.)
On the Measuring Receiver, press the blue key then press INSTR PRESET (the AUTOMATIC
OPERATION key) to preset the instrument. Press FREQ test it source's carrier frequency off. to approximately
On the Measuring Receiver, set the controls as
400 follows: and TRACK MODE. T h e the
MHz. Press TRACK MODE
AMFM
again to turn
MEASUREMENT..
LP FILTER..
DETECTOR
...............................................................
.....................................................................
>20
FM
AVG rev.02FEB88 4-15
Performance Tests Model W2A
6. Set the audio synthesizer hequency as shown in the following table. Set the Measuring Receiver
High Pass Filter shown in the table (as read on the Measuring Receiver). After setting in the table. as shown in the table. Set the audio synthesizer level to give the FM deviation
each
FM deviation, press
QM. For each setting, the Measuring Receiver’s display should read between the limits indicated r Audio
Synthesizer
Frequency (Hz)
200
1000
20 000
20 000
I
High
Pass
Filter
200
300
300 to make this measurement.
I
Connect the FM+32 output of
Average FM the
Deviation
(kHz)
250
250
4*
I
Lower
242.4
242.4
12.0
0.193
QM Limits (rad)
I
Actual Upper
257.6
257.6
-
AM/FM test source to the Measuring Receiver’s INPUT
Figure 4-3.) Press AUTOMATIC OPERATION, then MHz
Audio
Synthesizer
Frequency (Hz) Filter
000
000
200
High
Pass
300
300
300
Average FM
Deviation t k W
25
2.5
25
QM Limits (rad)
Lower Actual
2.39
0.239
24.0
24.0
Upper
-
-
QM Distortion
8. Connect the FM output of the AM/FM test source to the Measuring Receiver’s INPUT. (See
Figure 4-3.) Press AUTOMATIC OPERATION on the Measuring Receiver.
9. Set the audio analyzer’s oscillator to 1
test source. (See Figure 4-3.)
kHz. Connect its output to the audio input of the AM/FM
NOTE
For
this test, if the a d i o analyzer has mating input and output connectors, the
low
connector should be grounded. Connections high input or high output connector. should be made to the
10.
11.
On the Measuring Receiver, press
Set LP FILTER to 15 kHz.
QM. Set DETECTOR to PEAK+. Set HP FILTER
Adjust the audio analyzer’s oscillator level to give a display of 400 rad peak deviation. to 300 Hz.
rev. 02FEB88
Model 8902A Performance Tests
12. Connect the audio analyzer’s input to the Measuring Receiver’s MODULATION OUTPUT/
AUDIO INPUT. (See Figure 4-3.)
Set the audio analyzer to measure the distortion on the
Hz.
I
kHz signal at the MODULATION OUTPUT/AUDIO INPUT. Set the high-pass filter on the audio analyzer to 400 The distortion should be O.Io/o (-60 dB) or less.
13.
14.
QM 400 rad Peak Deviation; 1.5 MHz I F
Reduce the audio analyzer’s oscillator level to give a display of 40 rad peak deviation.
0.1%
On the Measuring Receiver, key in 3. I SPCL. The distortion measured on the audio analyzer should be 0.1% or less.
cPM
Distortion at 1 kHz Rate; 40 rad Peak Deviation; 455 kHz IF 0.1 To
4-17
Performance Tests Model 8902A
Performance Test 4-Audio Filters
Specification
Characteristic Performance Limits
I
Conditions
AUDIO FILTERS
50 Hz High-Pass (2 Pole)
3 dB Cutoff Frequency
Flatness
300 Hz High-Pass (2 Pole)
3 dB Cutoff Frequency
Flatness
3 kHt Low-Pass
Flatness
(5 Pole)
3 dB Cutoff Frequency
15 kHz Low-Pass (5 Pole)
3 dB Cutoff Frequency
Flatness
50 Hz nominal
<1%
300 Hz nominal
<1%
3 kHz nominal
<1%
>200 Hz rates
>1 kHz rates
<1 kHz rates
15 kHz nominal
<1% <lo kHz rates
>20 kHz Low-Pass (9 Pole Bessel)(’)
Flatness < 1%
<lo kHz rates
( I )
The >20 kHz low-pass filter is intended
I or minimum overshoot squarewave modulation.
1
I
Description
A signal is frequency modulated by a source which is known to have FM which is flat with rate. The flatness of the demodulated signal is then measured for various modulation filters.
NOTE
Equipment
AM/FM Test Source
Audio Synthesizer.
............................................................ H P
H P
1 I7 15A
3336C
Procedure
4-18
Model 8902A Performance Tests
HP 8902A
I
0 ::::."
0
0
:: :
1
0
0000 0
0000
0
INPUT
I
OUTPUT o
0
0
0 0 0 0 0
I t
OUTPUT
AUDIO SYNTHESIZER i
1. Connect the equipment as shown in Figure 4-4.
2. On the AM/FM test source, set the test mode to FM.
3. Set the audio synthesizer to 200 Hz at +6 dBm.
1. On the Measuring Receiver, press the blue
OPERATION key) to preset the instrument. Press FREQ and TRACK
AM/FM test source's carrier frequency again to turn it off. key
MODE. to approximately 100 MHz. Press TRACK MODE
5. On the Measuring Receiver, press MHz to center the instrument's tuning. Set the other controls as follows:
MEASUREMENT
DETECTOR
................................................................ F M
AVG
6. Set the audio synthesizer level to give a display of approximately 25 kHz average deviation.
7. Set the audio synthesizer frequency to the frequencies shown in the following table. For each setting, set RATIO on the Measuring Receiver to off,
RATIO to on (with LOG/LIN set for a set all H P or LP FILTERS to OK then set linear display), and insert the filter indicated. For each setting, the Measuring Receiver's display should read between the limits indicated in the table.
Audio
Synthesizer
Frequency (Hz)
2
1
200
000
000
10 000
1 000
100
10
1
10
1
000
000
000
000
Filter
50 Hz HP FILTER
50 Hz HP FILTER
300 Hz HP FILTER
300 Hz HP FILTER
3
3
15 kHz LP FILTER kHz LP FILTER kHz LP FILTER
15 kHz LP FILTER
>20 kHz LP FILTER
>20 kHz LP FILTER
Lower
98.99
98.99
98.99
98.99
98.99
98.99
98.99
98.99
98.99
98.99
Ratio Limits (% REL)
Actual Upper
101.01
101.01
101.01
101.01
101.01
101.01
101.01
101.01
101.01
101.01
4-19
Performance Tests Model 8902A
Performance Test 5-Audio Measurements
Specification
Characteristic
AUDIO FREQUENCY
COUNTER
Frequency Range
Accuracy(’)
Performance Limits
20 Hz to 250 kHz reference accuracy
-+3 digits reference accuracy
*0.02 Hz reference accuracy f0.2
Conditions
>1 kHz rate;
>lo% AM, >1.5 kHz FM, or >1.5 rad @M;
>lo0 mVrms external
<1 kHz rate;
>lo% AM, >1.5 kHz FM,
>lo0 mVrms external or >1.5 rad ‘PM;
<3 kHz rate;
1.5 to or
10% AM, 0.15 to 1.5 kHZ FM,
0.15 to 1.5 rad
(PM;
3 kHz low-pass filter
~~~ ~
AUDIO DISTORTION
Frequency Range
Residual Noise and Distort
Accuracy
Sensitivity
400 or 1000 Hz k5O/0
<0.3% (-50.4 dB) f l dB of reading
1.5% peak AM
150 Hz peak FM
0.6 rad peak
0.1 to 3 Vrms
20 Hz to 50 kHz bandwidth; <4OoC modulation modulation modulation external
AUDIO RMS LEVEL
Frequency Range
Voltage Range
Accuracy
50 Hz to 40 kHz
0.1 to 3 Vrms i4°/0
( I ) For demodulated signals, the residual noise generated by the Measuring Receiver must be accounted for in distortion measurements (that is, residual AM, FM, or M).
Description
All audio measurements are made on external audio signals. Level accuracy is measured by com- paring the voltage reading o n the Measuring Receiver with the output from a more accurately set audio oscillator. Residual distortion and noise is measured by making a dist.ortion measurement o n a
4-20
Model 8902A Performance Tests low-distortion oscillator. Measurements must be made at several frequencies within the notch filter range to verify proper nulling of the fundamental. Distortion accuracy is measured by summing low-distortion output from one oscillator with the output of an oscillator which is set second through fifth harmonic of known magnitude. The audio counter is checked signal from a audio frequency synthesizer set to both high and low levels. by to generate a a counting the
EQUIPMENT
Audio Analyzer
...................................................................
Audio Synthesizer.
HP 8903B
HP 3336C
PROCEDURE
Audio
Analyzer
Frequency (HZ)
50
500
5 000
40 000
Level Limits (Vrms)
Lower Actual Upper
2.88
2.88
2.88
2.88
-
3.12
5. Set the Audio Analyzer level indicated in the table. to 100 mV. Set the Audio Analyzer to the frequencies shown in the following table. For each setting, the Measuring Receiver’s display should read between the limits
Audio
An a I y z e r
Frequency (Hz)
40 000
Lower
96
96
96
96
Actual Upper
104
104
104
104 rev.
15NOV87
4-21
Performance Tests Model 8902A
Audio Counter Range and Sensitivity
6. On the Measuring Receiver, press FREQ. from the Measuring Receiver’s Audio Input. Connect the Audio Synthesizer output
Measuring Receiver’s Audio Input.
S (shift) then AUDIO Disconnect the Audio Analyzer to the
7. Set the Audio Analyzer to the frequencies and levels shown in the following table. For each setting, the Measuring Receiver’s display should read within the limits indicated in the table. i
~
Audio Synthesizer
Frequency (Hz)
20
20
1 000
1 000
250 000
250 000
Level (dBm)
+8
-13.0
-1 3.0
+8
+8
-13.0
I Freauencv Limits (kHz1
Lower Acutal
0.01998
0.01998
0.99997
0.99997
249.997
249.997
-
0.02002
-
-
1
Residual Noise and Distortion
8. Set the audio synthesizer to 380 Hz at -13 dBm (100 at the audio input).
9. On the Measuring Receiver, press
400 Hz DISTN (the PEAK- key).
S (shift) then AUDIO DISTN. Press the blue key then press
10. Slowly step the audio synthesizer up in frequency to 420 Hz using 2 Hz steps or finer. Note the highest distortion reading displayed on the Measuring Receiver. The highest reading should not exceed 0.3%.
Maximum Residual Distortion; 400 Hz Input at 100 mV: 0.3%
11. frequency to 380 Hz using 2 Hz
+16.5 a m . Slowly step the audio synthesizer down in steps or finer. Note the highest distortion reading displayed on the Measuring Receiver. The highest reading should not exceed 0.3%.
12.
Maximum Residual Distortion; 400 Hz Input at 3V
Set the audio synthesizer frequency to 950 Hz.
0.3%
13. On the Measuring Receiver, press the blue key then press 1 kHz DISTN (the PEAK+ key).
14. Slowly step the audio synthesizer up in frequency to 1050 Hz using 5 Hz steps or finer. Note the highest distortion reading displayed on the Measuring Receiver. The highest reading should not exceed 0.3%.
Maximum Residual Distortion; 1 kHz Input at 3 V 0.3%
15. frequency to 950 Hz using 5 Hz to dBm. Slowly step the audio synthesizer down steps or finer. Note the highest distortion reading displayed on the Measuring Receiver. The highest reading should not exceed 0.3%. in
Maximum Residual Distortion; 1 kHz Input at 100 m V 0.3%
4-22 rev.15NOV87
1
I
Model 8902A Performance Tests
Distortion
Accuracy
16.
17.
On the audio analyzer, set oscillator to 1 kHz 1V. its output float switch to the float position. Set the audio analyzer’s
Set the audio synthesizer to 2 off (but less than -50
W z as low as possible without switching the instrument as shown in
Figure 4-5. Note that the audio synthesizer is connected to the floating low output of the audio analyzer’s output. (This has the effect of summing the two outputs.)
HP 8902A
0
:;;ti
000000 0000 0
D
0
0
0 0000
JNPUT
AUDIO ANALYZER
I
OUTPUT
AUDIO SYNTHESIZER
Figure
4-6. Distortion Accuracy Performance Test Setup
Audio
Synthesizer
Frequency (kHt)
2
3
4
5 r
Distortion Limits (%)
Lower Actual Upper
0.89
0.89
0.89
0.89
-
1.12
1.12
24.
25.
26.
Set the audio analyzer’s oscillator frequency to 400 Hz without changing its level.
On the Measuring Receiver, press the blue key then press 400 Hz DISTN.
Set the audio synthesizer’s frequency as shown in the following table without changing the audio synthesizer’s amplitude. For each setting, the Measuring Receiver’s display should read between the limits indicated in the table. rev. 15AUG88 Performance Test 5-Audio Measurements 4-23
Performance Tests
Audio
Synthesizer
Frequency (Hz)
800
1200
1600
2000
Distortion Limits (“YO)
Lower
0.89
0.89
0.89
0.89
Actual Upper
1.12
-
1.12
Model 8902A
4-24
Model 8902A Performance Tests
Characteristic
POWER REFERENCE
Power Output
Power Output Accuracy
I
Performance Limits
I
1 mW
*1.20/0
Conditions worst case; for 1 year; 0 to 55OC
Description
The power from an external 1 mW power reference is measured with a power sensor and the power meter of the Measuring Receiver. The same power meter and sensor are then used to measure the power from the Measuring Receiver's power reference.
NOTE
Due fo acciiracy Iimilalions of'lhis &sf melh~d, the powtjr Iewl can only be wriJicd lo wifhin
&I.
9?v. Grwfcr ucciiracy cun bc obtuincd hy using a rcwnlly calibrafed tPxfxrLma1 powcv- rcjkrcncc. or by tollowing flic procdirre in Perfor- mance Test 7-Power Reference Accuracy (Using DC Substitution).
Equipment
Power Reference
Sensor Module
......................................................... HP 435A Opt
HP
KO5
I 1722A
Procedure
1. Connect the input of the sensor module (or a compatible power sensor connected to the
Measuring Receiver's SENSOR input) to the output of the external power reference.
2. On the Measuring Receiver, press RF POWER. Press RATIO and check that LOG/LIN is in the linear mode. (The display should read between 99.9 and lOO.Io/o REL.)
3. Connect the power sensor/input switch to the CALIBRATION RF POWER OUTPUT con-
RF Power Reference Accuracy: 98.1
4-25
Performance Tegts
Performance Test 7-Power Reference
(Using
DC Substitution)
SPECIFICATION
Model 8902A
POWER REFERENCE
- o w
POwerOutputAccuracy
1 mW fl.2% worst
case;
1 year; 0 to 55OC
DESCRIPTION
The power from the power reference oscillator is measured by a method this method
With no amount of a power-sensing thermistor is placed power applied, the the thermistor heats into balance. When re-balance it. for measurement direct
A
RF
dc
in
one arm of a self-balancing, voltage supplying the top of the bridge dc substitution. In resistance bridge. is automatically adjusted until to the temperature that produces the resistance required to bring the bridge
FtF power is applied to the thermistor, the thermistor heats up and momentarily to second bridge, which senses only the ambient temperature, is employed drift. Careful measurement of the bridge dc volfages provides power applied to the thermistor to a higher reading of the power meter. degree a way to the bridge to compensate determine the of accuracy than can be obtained to by
NOTE
The
A less accurate method of f1.2% by this procedure. for measuring the power reference can be found in the preceeding Performance Test 6-Power Reference (Using
Reference Comparison).
EQUIPMENT
Digital Voltmeter
Power Meter
Thermistor Mount
.................................................................
HP 3455A
.......................................................
HP 478A Opt H75 *
NOTE
* Must be calibrated at the National Bureau of Standurh (NBS) to obtain the accuracy
for
this test. See llzble 1-2 for critical specifications.
4-26 reu.lOJULk37
Model 8902A Performance Tests
PROCEDURE it but not
to
432A Power Meter switched off and the thermistor interconnect cable c o ~ e c t e d rear-panel VRF connector and pin end of the interconnect cable. Record the value of the mount resistance for should be approximately 20052.)
1 to the right of the key slot) on the thermistor future reference. (It
W
(R):
n
2. Connect the equipment as shown in floating. The positive input of the voltmeter should be connected to the rear-panel VCOMP connector of the HP 432A
Mount Resistance
The input of the digital voltmeter should be
Power Meter, the negative input to the connector. Switch the
NOTE
thk
point on do
not
handle the HP 478A in
order
to maintain its
the&
stab2ity
-
DIGITAL VOLTMETER
HP 432A
VRF
0
0
:::g
0 0
:
0
8888
0
0 rev.1 OJUL87
3.
4.
5. Fine
6.
On the Measuring Receiver, key in
Set the HP
ZERO to to obtain a zero meter indication. zero
Observe
Figure
4-6.
Power
Reference Performume Test Setup the
HP
Power Meter RANGE
432A Power to COARSE
Meter on the most sensitive range, then set the RANGE switch the voltage reading on the voltmeter. If the reading is greater than off.
400 pV, press and hold the FINE ZERO switch on the HP 432A Power Meter and adjust COARSE ZERO so that the voltmeter reads less than 200 pV then release the FINE ZERO switch. Record the voltmeter reading for future reference.
-
VRF with NO (Vo): Vdc
NOTE
Steps 6, 7, and 8 should be performed as quickly as possible to minimize d@.
7. On the Measuring Receiver, key in 45.16 SPCL. Record the voltmeter reading.
8.
- V’F with 1 mW (VI): Vdc
Connect the voltmeter to read VCoMp (with respect to chassis ground) on the HP 432A Power
Meter. (The voltmeter’s negative input should connect to chassis ground.) Record the voltmeter reading. with 1 mW: Vdc
4-27
Performance Tests
RF
Power Reference Power: 0.988
Model 8902A
9. Compute the power where mW.
H
P =
2VCOMP(Vl
- + v,2 -
v:
is the effective efficiency of the thermistor mount at 50 MHz as read from its label and
R
is the resistance measured in step 1. The computed power should be between 0.988 and 1.012
1.012 mW
4-28 rev. 1 OJUL87
Model 8902A Performance Tests
Performance Test 8-Power Meter
SPECIFICATION
Characteristic
RF POWER
RF Range Linearity(')
Performance Limits
RF Range-to-Range Change
Zero Set(2)
Error(') i0.02 f0.03 dB dB
*0.02 dB/RF range change from reference range
*0.5°/~ of full scale f l count
('1 Using Recorder Output, Using front-panel display, add
Decrease by a factor of ten for each higher range. fl count of least-significant digit.
RF ranges 2 to 5
RF range 1 on lowest range
DESCRIPTION
A power meter range calibrator is used to check the range-to-range error, in-range linearity, and zeroing integrity of the power meter circuits. divider in the range calibrator.
RF power ranging is simulated by a precision voltage
EQUIPMENT
Range Calibrator.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
,
. . . . . . . . . . . . . . .
,
. . . .
.
. . . . .
HP 1 1683A
PROCEDURE
Zero Set
1. Connect the power meter output of input. to the Measuring Receiver's SENSOR
2. On the range calibrator, set the function to standby, polarity to normal, and range to 1 mW.
3. On the Measuring Receiver, press the blue hey then press INSTR PRESET (the AUTOMATIC
OPERATION key) to preset the instrument. Press RF POWER. Press ZERO and wait for the instrument to zero.
NOTE
I f Error 15 is disylaycd, press 100 thcn lhr hliic key thcw tlrc> (40 CAL I'ACTOR kcy (thc
MHz key) to cnfcr a dirmmy calihrafion factor of 1OO?ii
4. On the Measuring Receiver, key in the special functions indicated in the following table. For each setting the Measuring Receiver's display should read as indicated in the table. (Take the average of several readings. Ignore the RECAL and UNCAL annunciators.)
I
4-29
Performance Tests
Serial Preflx 2305A
to
-
Special
Function
10.1
10.2
10.3
10.4
10.5
Actual
Power Reading
Maximum
0.00 pW
0.0 pw
0.000 rnW
0.00 rnW
0.0 f f f f rnW 1 count count count
Model 8902A
Serial Prefix 2 4 5 A and above: r
Special
Function
10.1
10.2
10.3
10.4
10.5
Actual
Power Reading
Maximum
0.000 pw f
0.00 pW 0.06
0.0 pw
0.000 rnW
0.00 rnW It
* f
1
0.051
0.2 count count
Range-to-Range Error
5. On the range calibrator, set the function to calibrate.
6. On the Measuring Receiver, key in 10.0 SPCL to set the power meter ranging to automatic.
Press CALIBRATE then press the blue key then press SAVE CAL (again, the CALIBRATE key). This normalizes the power reading to 1 mW. (The CALIBRATE key light should be on.)
7. On the Measuring Receiver, key in the Special Functions listed in the following table.
Receiver should be within the limits shown.
For each setting, set the range calibrator to the range indicated in the table. The reading on the Measuring
Special
Function
10.2
10.4
10.5
Range
Calibrator
Range
10 pw
100 pw
10 mW
100 mW
I
99.4 pw
9.94 rnW
99.0 mW
Power Reading Limits
100.6 pW
10.06 rnW
101.0 rnW
Accuracy within a
Range
8. Set the range calibrator’s range to 1 mW.
9. On the Measuring Receiver, key in 10.3 SPCL. Set the range calibrator’s range to 100 pW. The
Measuring Receiver’s display should read between 0.099 and 0.101 mW (0.100 m W Jt0.5% digit, then rounded to the nearest 0.001 mW).
&l
Accuracy within a Range: 0.099 0.101 mW
4-30 rev. 060CT86
Model 8902A Performance Tests
Performance
Test 9-SWR
Specification
-
Characteristic
RF POWER
Input SWR
TUNED RF LEVEL
Input SWR
Performance Limits
~
4.15
4 . 1
4.40
4 . 3 3
4.50
4.33
Conditions using HP 11722A Sensor Module at RF input; RF range 1 and 2 at RF input; RF range 3 at HP 11722A input; RF range 1 and 2 at HP 11722A input; RF range 3 at HP l1722A input; RF range 3 with Special Function
1.9 (1 0 dB RF and RF amplifier inserted)
Description
Input SWR loss. Measurements are made directly at the Measuring of a power sensor or sensor module connected to the Measuring Receiver. In either case, the input under test is driven by a signal generator through an SWR bridge. The reflected power is measured by a spectrum analyzer. A reference line is first established by disconnecting the output of the SWR bridge to create a high- reflection, open circuit. Since SWR for the tuned input levels below reflected signal.
0
RF level measurement mode is specified only for dBm, a spectrum analyzer is required to detect the much lower level of the
Equipment
Attenuator, 6
Signal Generator.
SWR Bridge..
....................................................
R F Spectrum Analyzer
Sensor Module
......................................................
8491A Option 006
HP 8559A/ 182T
HP 11722A
HP 8640B Option 002
Wiltron 60NF50
NOTE
The. log display accwriccy qfthc vptwriirn analyzer may hc irtadt%palc’.Ji7r this tc’.~(. If‘ any data points in thc following proccdrire appcar to he ncar or oiif OS limils, in its cheek proccdi ire. thc arnpli(iidc culib.a[ion rnaniiul and i i s o
(hi. datu a[ the spt~ctriim analyzer ohluintd rhiw
to us
dcscrihcd corrticl [he rcwil[.r. in this
I f a tracking gciwalor that is compa(ib1c with the> jbr tho .signal giwsralor, a swcyt
RF
spcctriirn aridyzcr is rncasiirorncwt can hz miidc.
4-3 I
Performance Tests Model 8902A
HP 8902A
SENSOR
I
SIGNAL GENERATOR
RF OUTPUT
INPUT RF INPUT
6 dB ATTENUATOR
SVR B R I N E
~ ~~
Figure 4- 7. S WR Pcflormance Tat Setirp
PROCEDURE
Sensor Module’s Power Sensor
SWR
NOTE
If
a sensor modirle is not available, pet$orm steps I fhroirgh 4 except set fhe signal gentrator fo -27 dBm.
Then confinire
on
On
af sfep the Measitring Receiver, press FREQ and key
14. in 1.0 MHz.
1. Connect the equipment as shown in Figure 4-7. Connect the 6 dB attenuator directly to the
RF input of the SWR bridge.
SWR bridge at this time.
Do not connect anything to the device-under-test input of the
2. Set the signal generator level to +3 dBm CW.
3. Set the spectrum analyzer to sweep 0 to 1 GHz. Set the display for 10 dB per vertical division.
4. With the sensor module disconnected from the SWR bridge, tune the signal generator from 0.1 to 1300 MHz and note the level of the signal. Adjust the spectrum analyzer’s reference level, as needed, to set the average level of the signal to a convenient graticule reference. Resweep the signal generator and note the reference on the display.
NOTE
If
the signal generator or sptWxm analyzer is incapable of‘ complcie covcv-age of the ficqircncy rangc: irsc whaicwr range is availahlc. the specirirm analyzer has variahlc persistence
or
storage capabilify, irse ii
to
store [he rt;ference line.
5. On the Measuring Receiver, press the blue key then press INSTR PRESET (the AUTOMATIC
OPERATION key) to preset the instrument. Press RF POWER. Connect the sensor module to the SWR bridge. (See Figure 4-7.)
4-32
Model 8902A Performance Tests
6. Resweep the signal generator and observe the level of the signal on the spectrum analyzer. At all frequencies between 2.5 and 1300 MHz the highest and lowest frequencies.) the signal should be 23 dB below the reference signal.
(Repeat the above steps and adjust the spectrum analyzer sweep, as required, to gather data for
Worst Case Return Loss for RF Power Measurement: -23 dB
Sensor Module’s
Thru-Path SWR
7. On the Measuring Receiver, press attenuation to 50 dB (range 1)
FREQ. Key in 1.6 SPCL and and manual tune the instrument.
1.0 MHz to set the input
NOTE
In the steps that jollow, ignorc error mtwages in fhc Measwing Receiver’s display. Thp messages indicate that the ins,rurnenr is not tirned to the inpiil signal. Also ignow any spirrioiis signals on the spwtrirm analyzer display. Thc signals originale with the
Measuring Rmivcr S local oscillator.
8. If necessary, re-establish the reference on the spectrum analyzer (with the sensor module disconnected from the SWR bridge). Then with the sensor module connected to bridge, resweep the signal generator. At all frequencies between 2.5 and 1300 should be 17 dB below the reference signal.
MHz, the SWR the signal
Worst Case Return Loss for Tuned RF Level Measurement;
External Sensor Module; Range 1: -17 dB
9. On the Measuring Receiver, key in 1.2
Repeat step 8.
SPCL to set the input attenuation to 10 dB (range 2).
Worst Case Return Loss for ‘Tuned RF Level Measurement;
External Sensor Module; Range 2: -17 dB
10. Set the signal generator level to -27 dBm.
11. With the sensor module disconnected from the SWR bridge, sweep the signal generator as before and establish a convenient reference on the spectrum analyzer’s display.
12. Reconnect the sensor module to the SWR bridge. On the Measuring Receiver, key in 1.7 SPCL to set the input gain to
1300 MHz,
24
dB.
Resweep the signal generator. At all fiequencies between the signal should be 14 dB below the reference signal.
2.5 and
Worst Case Return Loss for Tuned RF Level Measurement;
External Sensor Module: Range 3: -14 dB
13. On the Measuring Receiver, key in 1.8 generator. At all frequencies between 2.5 and reference signal.
SPCL to set the input gain to 14 dB. Resweep the signal
1300 MHz, the signal should be 17 dB below the
Worst Case Return Loss for Tuned RF Level Measurement;
External Sensor; 14 dB Gain Range: -17 dB rcv. I8DEC86 4-33
Performance Tests Model 8902A
Measuring Receiver Input SWR
14. Disconnect the sensor module from the SWR bridge and the Measuring Receiver’s input.
Connect the
(See Figure
SWR
4-7.) to the Measuring Receiver’s INPUT connector.
15. On the Measuring Receiver, key in 1.7 SPCL. Resweep the signal generator. At all frequencies between 2.5 and 1300 MHz, the signal should be 16 dB below the reference signal.
Worst Case Return Loss for Tuned R F Level Measurement;
Measuring Receiver Input; Range 3:
16. Set the signal generator level to +3 dBm.
-16 dB
17. Remove the SWR bridge from the Measuring Receiver’s input. Sweep the signal generator as before and establish a convenient reference on the spectrum analyzer’s display.
18. Reconnect the SWR bridge to the Measuring Receiver’s INPUT connector. On the Measuring
Receiver, key in 1.2 SPCL. Resweep the signal generator. At all frequencies between 2.5 and
1300 MHz, the signal should be 22 dB below the reference signal.
Worst Case Return Loss for Tuned RF Level Measurement:
Measuring Receiver Input; Range 2:
19. On the Measuring Receiver, key in 1.6 SPCL. Repeat step 18.
-22 dB
Worst Case Return Loss for Tuned RF Level Measurement;
Measuring Receiver Input; Range 1: -22 dB
4-34
Model 8902A Performance
Tests
Performance Test 10-Tuned
RF
Level (Using a Step Attenuator)
Specification
Characteristic
TUNED RF LEVEL
Frequency Range
Power Range
Relative Measurement
AcCuracy(1)
Detector Linearity
IF Range-teRange Error(2)
RF Range-to-Range Error
Frequency Drift Error
Noise Error(3)
Performance Limits
2.5 to 1300 MHz
0 to
0 to
-127 dBm
-100 dBm using IF synchronous detector using IF average detector
+
IF range-to-range error
+
RF range-twange e m frequency drift error noise error *1 digit f0.02 f0.04 dB dB f0.02 dB/IF range change f0.05 dB/IF range change f0.04 dB/RF range change f0.06 dB/RF range change f0.05 drift from center of IF f0.18 dB
IF synchronous detector
IF average detector
IF ranges
IF range
1
6 to
7
5 tuned RF level
RF power to tuned RF level
( l )
Accuracy is specified only at constant temperature and after RF range calibration is completed. Accuracy
(2)
(3) is affected
50 using
IF ranges by the residual FM of the source under test. If the approximately average detector. kHz bandwidth)
Using the IF synchronous detector
1.9 measured over a the
6 7
-1 is implemented.
30s
IF average detector period in a 3 by peak residual FM deviation is greater than using Special Function 4.4.
10 dBm for the IF synchronous detector, and below approximately and for levels i-120 dBm, or for levels i-110
-85 dBm if dBm for
Special the IF
Function
Description
This
test checks synchronous internal that held. is dc near
The and IF relative accuracy of the average detectors. voltmeter)
The tuned RF level measurement mode for both the linearity of the detectors (including by feeding a 50 the linearity
MHz of
IF' the signal through a calibrated step attenuator into the Measuring Receiver. The instruments are set to produce a signal the upper measurement limit of attenuation i s
is
checked first. Linearity is measured then increased the increase in attenuation. by the detector, a level reference is set, and the range settings
10 dB and the drop in displayed level is compared against rev.13JUL87 4-35
Performance Tests Model 8902A
IF gain step accuracy is measured by setting the instruments overlap region of adjacent IF correcting for the detector linearity error) is the to produce a signal level gain steps. The change in the displayed level for each
IF gain step error. gain that is in the change (after
Fhquency
drift
error is measured for each detector is fine tuned slightly. by noting the change in level as the signal frequency
NOTE
The output level accuracy of the signid generator a piston attenuator is accurately calibmted. is of secondary importance.
The test may be performed at other frequencies where the step attenuator or
An alternate procedure which uses a piston attenuator over a wide attenuation range is found in Performance Test l l - l h e d RF Level (Using a Piston
Attenuator).
Equipment
Attenuator, Step 10
Signal Generator
.................................................................
Option
HJ? 864OB
Procedure
NOTE
In the following procedure the signal generator can be connected either to a sensor module (which is connected
to
the Measuring Receiver) to the Measuring Receiver’s INPUT connector. The procedure the W e r case. is
or
directly written for
Ignore the UNCAL and RECAL annunciators and error messages as they appeur in the display.
Detector Linearity
1. Set the one-half hour.
2. Set the 10 b. signal generator
Key in c. Key in
S (shift)
4.6
1.2 to 50 step attenuator
MHz
to 10 and connect it directly
TUNED RF LEVEL.
SPCL to select the
CW at dB
+3 a m . Allow the equipment
SPCL to set the input attenuation to 10 d. Key in 9.2 SPCL to set the e.
IF gain to 10 dB.
Key in 49. S SPCL to display the voltage into the IF Average Detector. (Pressing
S and 1 will cause “b” to appear in the display.) Adjust the signal generator level for a reading of approximately 3.0 (3 f. Press CLEAR.
IF average detector with a measurement averaging time of 1s. dB. to warm up at least to the Measuring Receiver’s
INPUT connector. Connect the signal generator’s output to the attenuator.
3. On the Measuring Receiver, press the blue key then press INSTR PRESET (the AUTOMATIC
OPERATION key) to preset the instrument. Allow the Measuring Receiver to find the input signal and measure its frequency, then press the MHz key.
4.
5.
Set the signal generator level to -7 dBm.
On the Measuring Receiver, key in the following: a. Key in
4-36 rev.
13JUL8
Model 890% Performance Testa
6. g. Press the blue key then press SET
If steps where the fador between 0.9931 and dB).
REF (the ZERO key) it does not, press the blue key and SET
Set the step attenuator as
-20.015 dB,
0.3148/0.3153 = to 20 a ratio rather than percent dB)
For step is is 0.9984.
-10.025 dB.
REF
again.)
10 dB to dB).
10 to 20
The computed result should be step is enter the
(that is, a ratio of
-9.990 tuned dB
RF attenuator
100.01%. and for the 20 dB dB a ratio, compute the computed result
8.
9.
Set the attenuator back a. Key in c. d. of 1s.
Press and dB).
4.2 SPCL
50.6
100.01%. to to
SPCL
10 dB. select the IF
IF Average Detector Linearity: to
0.9954 1.0046 synchronous detedor with a measurement averaging time to display the voltage into the IF Synchronous Detector. fine adjust the signal generator level for a reading of approximately
PressCLEAR. the blue key and to
SET
20
REF. dB.
(The display should read,
Divide the result in the Measuring Receiver’s display
10 to 20 dB steps (as
3.0 (3 done in step 6).
If
Vdc). necessary, on the average, between was again.)
99.99 by the
Record the computed result for future reference. The computed result should be between 0.9977 and 1.0023
(k0.02
IF Synchronous Detector Linearity: 0.9977 1.0023
IF Range-to-Range Accuracy
11.
Set the step attenuator back
On the Measuring Receiver, key in to set the
12. On the step attenuator, step up the attenuation in 10
For each attenuator setting perform the following: a. to 10
Press the blue key then SET dB.
SPCL
REF
to establish b. Key in the Special h c t i o n listed in the table. dB a
IF gain steps as
0 indicated in the following table. level reference. c. Note the average value of several readings and record the result in the table. d. Multiply the result recorded in step c by the result of step and record the computed result for future reference. The computed result should be within the limits indicated in the table.
-
1
2
3
4
-
Attenuation
of step
; 1:::
9 s
9.6
9.7
Kev ii
Displayed
Result
4%)
4.1 SPCL at this
Lower
99.77
99.77
99.77
99.77
99.43
99.43
Actual Upper
-
-
4-37 rev.13JUL87
Performance Testa Model 8902A
Frequency
Drift
Error
13. Set the step attenuator until Error 01 to 10 dB. the SET REF key. Fine tune the appears, stopping
4.2 signal
SPCL. Key in intervals
9.2 to
SPCL. Press the blue
10 shift key and range, or note the display. Note the maximum and minimum value on the Measuring Receiver’s display. The difference between the maximum and minimum values should be less than 12.20
IF Synchronous Detector Frequency Drift Error: 12.2%
4-38 rev.
13JUL87
Model 8902A Performance
Tests
Performance Test
11
-Tuned
Specification
RF
Level (Using a Piston Attenuator)
Performance Limits Conditions
TUNED RF LEVEL
Frequency Range
POWEK Range
2.5 to 1300 MHz
0 to -127 dBm
0 to -100 dBm using IF synchronous detector using IF average detector
Relative Measurement
Accuracy(')
Detector Linearity
IF Range-teRange Error(2)
RF Range-to-Range Error
Frequency Drift E m
+
+
IF range-to-range
RF range-to-range error frequency drift error noise error fl
error
diiit f0.02 dB f0.04 f0.02 f0.05 dB/IF range change dB/IF range change f0.04 dB/RF range change f0.06 change f0.05 drift from center of IF
IF synchroMxrs detector
IF average detector
IF ranges 1 to 5
IF range 6 to 7 tuned RF level
RF power to tuned RF level
Noise Error(3)
(l)
Accuracy is specified only
(2)
(3) is affect& by using the
IF ranges 6
Using the IF the and residu&
7 a are
at
constant temperature and after
FM of the sour& under test. If period used approximately -1 10 dBm for average detector.
in
a 3 kHz bandwidth, tuned RF level in automatic operation only for tuned measurements
RF should be level measurements made below the IF synchronous detector, and below approximately -85 dBm for the IF synchronous detector and for levels i-120 dBm, peak residual FM deviati& is greater than or range calibration is completed. Accuracy
4.4. for levels i-110 dBm if Special Function
Description
This test checks the relative accuracy of the tuned RF level measurement mode for both the IF' synchronous and IF average detectors. The linearity of the detectors (including the linearity of the internal dc voltmeter) is checked first. Linearity is measured by feeding a 30 MHz signal through a calibrated piston attenuator into the Measuring Receiver. The instruments are set to produce a signal that is near the upper measurement limit of the detector, a level reference is set, and the range settings held. The attenuation is then increased by 10 dl3 and the drop in displayed level is compared against the increase in attenuation. rev.15SEP88 4-39
Performance Testa Model 8902A
IF
gain step accuracy is measured by increasing the attenuation of the piston attenuator in 10 steps and comparing the displayed reading with the increase in attenuation. dB
Frequency drift error is measured for each detector by noting the change in level as the signal frequency is fine tuned slightly.
NOTE
The
output level accuraqy of the
test
(Using mqy be is
accurately calibrated.
is
found
signal
in generator
An
&mate procedure
which
uses a calibrated 10
is
of secondary importance. performed at other frequencies where the piston attenuator
dB
10-bed RF Level
Equipment
Attenuator, 3 dB
Signal Generator
(2
Attenuator, Piston required)
............................................
HP 8491A
.................................................................
Option
Eaton Type
HP
03
864OB
Procedure
NOTE
In
the
following procedure an external sensor sensor module
is module is
not used. If a connected to the Measuring Receiver, disconnect it. Use
short
interconnect cables to prevent leakage from the input of the attenuator to
the
input
of the
Measuring Receiver. !#-$le-shielded coaxial
cable is
recommended.
4-40
Detector Linearity
1.
2.
Set the signal generator to 30 MHz CW at +10 dBm.
Allow
the equipment to warm up at least one-half hour.
Set the piston attenuator to 10 dB. Connect one fixed attenuator’s input and connect the other end of the 3 cable to the signal generator’s output connector.
3 dB attenuator directly to the piston dB attenuator through a short, well-shielded
3. Connect the other fixed 3 the other end of the 3 dB dB attenuator directly to the piston attenuator’s output attenuator to the Measuring Receiver’s INPUT. and connect
4. On the Measuring Receiver, press the blue key then press INSTR PRESET (the AUTOMATIC
OPERATION key) to preset the instrument. Allow the Measuring Receiver to find the input signal and measure its frequency, then press MHz.
NOTE
In the following steps, ignore the RECAL
and
UNCAL annuncbtors and error messages.
5. On the Measuring Receiver, key in the following: a. Key in S (shift) TUNED RF LEVEL. b. Key in 4.6 SPCL to select the IF average detector with a measurement averaging time of 1s.
rev.15SEP88
Model 8902A Performance Tests
6. c. Key in 1.2 SPCL to set the input attenuation to 10 d. Key in 9.3 SPCL to set the IF gain to 20 dB. dB.
On the Measuring Receiver, key in display the voltage from the IF
49. S (shift) 1 SPCL to set the instrument
S and 1 will cause to measure and
"b" to appear in the display.) Adjust the signal generator level for a reading of approximately 3.0 (3 Vdc).
The piston attenuator attenuation setting (20
two
3
to
obtain the 3
Vdc
dB
residual
reading. dB,
NOTE
have
30 insertion
If
the piston attenuator adjust the dB loss insertion loss at the plus the added 10 signal
has
dB). as dB
The needed
7. Press CLEAR key) to set the displayed reading
100.01%. If to re-enter tuned RF level. Press the blue key then press SET REF (the a reference. (The display should read between it does not, press the blue key and SET REF again.)
ZERO
NOTE
If
calibration data is supplied with the piston attenuator, use the data in all
for
the attenuator error.
8. dB expressed in to 20 dB. 31.48 and 31.77% (that is,
%).
9. Set the piston attenuator back to 10
IF Average Detector Linearity: 31.48 dB.
31.77%
10. On the Measuring Receiver, key in measurement averaging time of 1s.
4.2 SPCL
9.1 to select the
SPCL to set the
IF synchronous detector with a
IF gain to 0 dB.
11. On the Measuring Receiver, key in 50.6 SPCL to set the instrument to measure and display the voltage from the approximately 3.0.
IF synchronous detector. Lower the signal generator level for a reading of
12.
13. Set the piston attenuator
-10f0.02
If it does not, press the blue key and SET REF again.) dB). to 20 dB.
99.99 and
The display should read between 31.55 and 31.70% (that is,
IF Synchronous Detector Linearity: 31.55 31.70%
IF
Range-to-Range
Accuracy
14. Set the piston attenuator back to 10 dl3.
15. Set the piston attenuator as indicated in the following table. For each step, key in the special function indicated in the table. For each step the display should read within the limits indicated in the table.
rev. 15SEP88
4-41
Performance Tests Model 8902A
Special
Function
9.1
9.2
9.3
9.4
9.5
9.6
9.7
Attenuation of Piston
Attenuator (dB)
10
20
30
40
50
60
70
Limits of Displayed Result (96)
Lower Actual
Ref upper
31.55
9.954
3.141
0.9908
0.31 15
0.09795
31.70
10.046
3.1 84
1 .ON3
0.321 0
0.10209
Frequency
Drift
Error
16. On the Measuring Receiver, key in 9.1 SPCL.
17. Set the piston attenuator to approximately 10 dB.
18. On the Measuring Receiver, press the blue generator slowly up and frequent intervals than 12.20% (1.0 dB). down over a kHz key and the range, or
SET REF until an Error key. Fine tune the signal
01 appears, stopping at the maximum and minimum value on the Measuring
Receiver’s display. The difference between the maximum and minimum values should be less
IF Synchronous Detector Frequency Drift Error: 12.20%
4-42 rev.15SEP88
Model 8902A Performance Tests
Performance Test 12-High-Selectivity Filters (Options
032
and
033)
Specification
SELECTIVE POWER: Filter Shape
-- 11111111111.11
4-44’ 0 2 4 6 1 1 0 1 1 1 4 1 O i 8 1
RELATWE FREQUENCY (kHz)
12.5 kHz Filter Shape (Option 032) 25 W z Filter Shape (Option 033)
Description
The accuracy of the high-selectivity filters is tested by feeding a 455
IF is determined. kHz CW signal directly into the
IF via the front-panel input connector. As the frequency of the input is changed, the shape of the
Equipment
Signal Generator.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 8640B or HP 3336C
4-43
Performance Tests
Procedure
Model 8902A
NOTE
In thc following procediirc the signal gcncrator can he connected either to a sensor modiilc (which is conncctcd to the Mcasiiring Rcctiver) or directly to the Measirring Reccivcr’s INPUT conncctor. The procediirc is writtcn for the latter case
Initial Setup
1. Set the signal generator to 455.0 kHz CW at +3 dBm. Connect the signal generator’s output to the Measuring Receiver’s INPUT. Allow the equipment to warm up at least one-half hour.
“Wide” Filter Test-Option Combination 032 and 037
2. On the Measuring Receiver, key in the following: a. Press the blue key then press INSTR PRESET (the AUTOMATIC OPERATION key) to preset the instrument. b. Key in 100 MHz to inhibit automatic tuning. c. Key in 24.0 SPCL to initialize the high-selectivity level measurement. d. Key in 3.1 SPCL to remove the RF input high-pass filter. e. Key in 24.1 SPCL to read the IF level.
3. Slowly tune the frequency of the signal generator up and down until the peak reading is found.
4. On the Measuring Receiver, key in 24.1 SPCL and 24.2 SPCL
IF level as a level reference. (The display should read 0 dB.) to establish and display the current
5. Tune the signal generator down until the first minimum is found. The display should read -2 dB or higher (that is, between -2 and 0 dB).
12.5 kHz Filter: Loss at First Minimum: -2 dB
6. Tune the signal generator down until the display reads -6.00 dB. Record the signal generator’s frequency.
12.5 kHz Filter: Lower 6 dB Frequency: kHz
7. Tune the signal generator down negative).
1.6 kHz. The display should read -30 dB or less (that is, more
12.5 kHz Filter: Loss at 1.6 kl-iz Below Lower 6 dB Corner: -30 dB
8. Tune the signal generator down another 3 kHz. The display should read -80 dB or less.
12.5 kHz Filter: Loss at 4.6 kHz Below Lower 6 dB Corner: -80 dB
9. Tune the signal generator up until the display reads 0 dB, then continue on until the display reads -6.00 dB. Record the signal generator’s freqirency.
12.5 kHz Filter: Upper 6 dB Frequency: kHz
10. Subtract the reading of step 9 from the reading of step 6. The difference should be between 6.4 and 10.4 kHz.
12.5 kHz Filter: 6 dB Bandwidth: 6.4 10.4 kHz
4-44
Model 8902A Performance Tests
11. Tune the signal generator up 12 kHz above the frequency recorded read -30 dB or less. in step 6. The display should
12.5 kHz Filter: Loss at 12 kHz Above Lower 6 dB Corner:
12. Tune the signal generator up another 3 kHz. The display should read -80 dB or less.
-30 dB
12.5 kHz Filter: Loss at 15 kHz Above Lower 6 dB Corner: -80 dB
“Wide” Filter Test-Option Combination 032 and 033 or 033 and 037
13. Perform step I, then on the Measuring Receiver, key in the following: a. Press the blue key then press INSTR PRESET (the AUTOMATIC OPERATION key) to preset the instrument. b. Key in 100 MHz to inhibit automatic tuning. c. Key in 24.0 SPCL to initialize the high-selectivity level measurement. d. Key in 3.1 SPCL to remove the RF input high-pass filter. e. Key in 24.1 SPCL to read the IF level.
14. Slowly tune the frequency of the signal generator up and down until the peak reading is found.
15. On the Measuring Receiver, key in 24.1 SPCL and 24.2 SPCL to establish and display the current
IF level as a level reference. (The display should read 0 dB.)
16. Tune the signal generator down until the first minimum is found. The display should read -2 dB or higher (that is, between -2 and 0 dB).
25 kHz Filter: Loss at First Minimum: -2 dB
17. Tune the signal generator down until the display reads -6.00 dB. Record the signal generator’s frequency.
25 kHz Filter: Lower 6 dB Frequency: kHz
18. Tune the signal generator down 1.6 kHz. The display should read -30 dB or less (that is, more negative).
25 kHz Filter: Loss at 1.6 kHz Below Lower 6 dB Corner: -30 dB
19. Tune the signal generator down another 3 kHz. The display should read -80 dB or less.
25 kHz Filter: Loss at 4.6 kHz Below Lower 6 dB Corner: -80 dB
20. Tune the signal generator LIP until reads the display reads 0 dB, then continue on until the display
-6.00 dB. Record the signal generator’s frequency.
25 hHz Filter: Upper 6 dB Frequency: kHz
21. Subtract the reading of step 20 from the reading
12.4 and 16.9 kHz. of step 17. The difference should be between
25 kHz Filter: 6 dB Bandwidth: 12.4 16.9 kHz
22. Tune the signal generator up 18.5 kHz above the frequency recorded in step 17. The display should read -30 dB or less.
25 kHz Filter: Loss at 18.5 kHz Above Lower 6 dB Corner: -30 dB
4-45
Performance Tests Model 8902A
23. Tune the signal generator up another 3 kHz. The display should read -80 dB or less.
25 kHz Filter: Loss at 2 1.5 kHz Above Lower 6 dB Corner: -80 dB
“Narrow” Filter Test-Option Combination 032 and 033 or 032 and 035
24. Perform step 1, then on the Measuring Receiver, key in the following: a. Press the blue key then press INSTR PRESET (the AUTOMATIC OPERATION key) to preset the instrument. b. Key in 100 MHz to inhibit automatic tuning. c. Key in 24.0 SPCL to initialize the high-selectivity level measurement. d. Key in 3.1 SPCL to remove the RF input high-pass filter. e. Key in 24.3 SPCL to read the IF level.
25. Slowly tune the frequency of the signal generator up and down until the peak reading is found.
26. On the Measuring Receiver, key in 24.3 SPCL and 24.4 SPCL to establish and display the current
IF level as a level reference. (The display should read 0 dB.)
27. Tune the signal generator down until the first minimum dB or higher (that is, between -2 and 0 dB). is found. The display should read -2
12.5 kHz Filter: Loss at First Minimum: -2 dB
28. Tune the signal generator down until the display reads frequency.
-6.00 dB. Record the signal generator’s
12.5 kHz Filter: Lower 6 dB Frequency: kHz
27. Tune the signal generator down negative).
1.6 kHz. The display should read -30 dB or less (that is, more
12.5 kHz Filter: Loss at 1.6 kHz Below Lower 6 dB Corner: -30 dB
30. Tune the signal generator down another 3 kHz. The display should read -80 dB or less.
12.5 kHz Filter: Loss at 4.6 kHz Below Lower 6 dB Corner: -80 dB
31. Tune the signal generator reads -6.00 up until the display reads 0 dB. then continue on until the display dB. Record the signal generator’s frequency.
12.5 kHz Filter: Upper 6 dB Frequency: kHz
32. Subtract the reading of step 31 from the reading of step 28. The difference should be between
6.4 and 10.4 kHz.
12.5 LHz Filter: 6 dB Bandwidth: 6.4 10.4 kHz
33. Tune the signal generator up 12 kHz above the frequency recorded in step 28. The display should read -30 dB or less.
12.5 kHz Filter: Loss at 12 kHz Above Lower 6 dB Corner:
34. Tune the signal generator up another 3 kHz. The display should read -80 dB or less.
-30 dB
12.5 kHz Filter: Loss at 15 kHz Above Lower 6 dB Corner: -80 dB
4-46
Model 8902A Performance Tests
‘Narrow” Filter lest-Option Combination 033 and 035
36.
37.
38.
On
dB
Press the or
IF
the the
blue b. Key in 100 MHz c. d.
e.
Ke