Description and
Operating Manual
Selective Level Meter
with wideband section
frequency range, 10 kHz to 160 MHz
SPM-16
SELECTIVE LEVEL METER
SPM-16
with wideband section
frequency range, 10 kHz to 160 MHz
Description and Operating Manual 874 A
1.7.81 Loe
0.2.7.81 2815
Wandel & Goltermann
Subject to change without not1ce
Printed in the Federal Republic of Germany
PRECISION ELECTRONIC
MEASURING INSTRUMENTS
C 0 N T E N T S
INTRODUCTION
1
SPECIFICATIONS
1.1
1.1.1
1.1.2
1.1.3
1.1.4
1.1.4.1
1.1.4.2
1.1.4.3
1.1.4.4
1.1. 5
1.1.6
1.2
1.2 .1
l. 2. 2
1.2.2.1
1.2.2.2
1.2.2.3
l. 2. 3
1.2.3.1
1.2.3.2
1. 2. 4
1. 2. 5
1.2.5.1
1.2.5.2
1. 2. 6
1. 2. 7
1.2.7.1
1.2. 7.2
1.2.7.3
1.3
1. 3.1
l. 3. 2
1.4
l. 4.1
...................................................
1-1
Frequency •....•......•..•.•.....•.•.•...••.•••........ 1-1
Frequency range for selective and wide-band
measurements .......................................... . 1-1
Frequency d. i s p. 1ay ...................................... . 1-1
Frequency tun1 ng ••.•••••••••••••••••••••••••••.••.•••. 1-1
Automatic frequency sequences •.•.•.•••.•.••••••••••••• 1-1
Frequency Search ••••••••••••••••••••••••.••••.••••••••
Auto Step
"
Tracking ................•........................... ~ ~ .
Sweep Frequency Operation ••• ~ ••••••••••.•••.••••••••••
Automatic Frequency Control (AFC) ••.••••••••••.•.•••••
Error limits of the tuned frequency ..••••••.•••.•••.••
1-1
....... .................................... . 1-1
1-2
1-2
1-2
1-2
Level ................................................. 1-2
Measured parameters ••••••••••••.••••.•••••••••••••••••
Result indication, resolution, range selection ••••••••
Result Indication ••••••••••••.••••••••••••••.•.•••••.•
Resolution •••••••••.••••••••••.•••••••••••••••.•••••••
Range Selection •••••••••.•.••..••.•.••.••.••.•.••••...
Measuring ranges ••••••••.•••••••••••••••••••••..•..•.•
Abso 1ute 1evel ••••••••••••••••••••••.•••••.••.•••••.••
Reduced Level ••••.•.••••••••.•••.•.•••••••••••••.••.•.
Automatic level calibration •••••••••••.•.••••••••.••••
Basic interference •.•••.•••.••••••••..•••••..•.•.•••..
Intrinsic Noise Level ••••••••••.••••••••••••••.••.••••
Level of interference lines ...........................
Fast signal detector for rapid signal identification,
active only with analog display ••.••••••.••••.•.••••.•
Errors of the level indication .••••••••••••••••.••••••
Errors in Selective Mode ••••••.•.•••••••••..•••••••.••
Variation of level reading with frequency,
Selective Mode •..••.••••••••.•••••••••••••.••.••••..••
Error in Wideband Mode •••••.•••••.•.•••.•..••••••.•••.
Phase jitter ••••.••.••.••••.••••••••••••••.•••••••••••
Measuring range ••••••••••••••••••••••••••.••.••..•••••
Error limits of the indication •••••••••.•••••••••••.•.
Selectivity and harmonic ratio ••••••••••••••.•••••.•••
Selectivity, switchable: 25 Hz/400 kHz/1.74 kHz/
1-2
1-3
1-3
1-3
1-3
1-4
1-4
1-4
1-4
1-5
1-5
1-5
1-5
1-5
1-6
1-6
1-7
1-7
1-7
1-7
1-8
3.1 kHz/48 kHz ......••..•.•••.•.•..•.•..••••.•.....•.. 1-8
1.4.2
1. 4. 3
1.4.3.1
1.4.3.2
1.4.4
Image frequency rejection and if suppression •••.•.••••
Distortion products •••••••••••••••••••••.•••••••••.•.•
Harmonic Distortion Products •••••••.•••••.••••••••••••
Non-harmonic Distortion Products •.••..••••••••••••••••
Noise power ratio NPR ••••••••••.••••..•••...•••.•..••
1-8
1-8
1-8
1-9
1-9
1.5
1.5.1
1. 5. 2
1. 5. 3
1. 5.4
1. 5. 5
1.6
1.7
1. 7.1
1. 7. 2
1. 7. 3
1. 7.4
1. 7. 5
1. 7. 6
Additional inputs and outputs ••••••••••••••••••••••••
Input for external standard frequency •••••••••••.••••
Output for standard frequency ••••••••••••••••••••••••
Output for control frequency •••••••••••••••••••••••••
1-10
1-10
1-10
1-11
IF output··"·····················~~~··················· 1-11
Y-Output voltage (DC) ••••••••••.••••••••••••••••••••• 1-11
X-Output voltage (DC) •••••••••••••••••••••••••••••••• 1-11
1. 7. 7
Dernodul ator output ..•.•...........•........••....•... 1-11
1. 7. 8
1. 7. 9
Display unit connection socket ••••••••••••••••••••••• 1-12
Interface Bus (lEe 625) (with auxiliary device
BN 853/02)
···················~~······················· 1-12
1-12
1.11
1.11.1
1.11.2
1.11.3
1.12
1.12.1
Digital interface ••••••••••••••••••••••••••••••••••••
Power supply connection for Test Probe TK-11 •••••••.•
Tracking generator output •••••••••••••••.••••••••••••
Memories for fixed frequencies and SPM-16 settings ••.
Number of fixed frequencies ••••••••••••••••••••••••••
Number of equipment settings •••••••••••••••••••••••••
Power supplies and ambient conditions ••••••••••••••••
Power supplies ••••.••••••••••••••••••••••••••••••••••
Operating climate ••••••••••••••••••••••••••••••••••••
Dimensions, weight •••••••••.••••••••••••••••••••••••.
Auxiliary devices ••••••••••••••••••••••••••••••••••••
EPROM, Order No. BN 874/00.01 ••••••••••••••••••••••••
Interface Bus (IEC 625) Card BN 853/02 •••••••••••••••
Printer interface, BN 905/02 •••••••••••••••••••••••••
Measuring accessories ••••••••••••••••••••••••••••••••
Test Probe TK-11, active Test Probe (series D••• ) ••••
1.12. 3
1.12.4
1.12.5
1.13
Adapter FEDA-1 (75 Q/50 Q) •••••••••••••••••••••••••••
RE0-50/RE0-56 matching transformer •••••••••••••••••••
Two-way splitter REV-56 ••••••••••••••••••••••••••••.•
Ordering information •••••••••.•••••••••••••••••••••••
1.7.10
1.7.11
1.7.12
1.8
1. 8.1
1. 8.2
1.9
1.9.1
1.9.2
1.10
2
Measurement periods .a.ee•••e••····~··················· 1-9
Level measurements with autoranging, automatic
calibrator switched off •••••••••••••••••••••.••••••••• 1-9
Level measurement with adjustment of the measuring
range and the wide-band drive signal via an IEC-Bus ••• 1-9
Lengthening of the measurement periods when
automatic calibrator is switched on •••••••••••.•••.•• 1-10
Phase jitter measurement •••••••••••••••••••••.••••••• 1-10
Data transfer, transfer time per character ••••••••••• 1-10
Input for measuring •••••••••••••••••••••••••••••••••• 1-10
BN 853/02)
·················••e•···G>··················
TECHNICAL DETAILS ••••••••••••••
2.1
2.1.1
2.1. 2
2.1. 3
2.1. 4
2.1. 5
1-12
1-12
1-12
1-12
1-13
1-13
1-13
1-13
1-14
1-14
1-14
1-14
1-14
1-14
1-14
1-12
1-16
1-17
1-17
1-18
o ••••••••••••••••••••••••••••
2-1
Receiver Section ••••••••••••••••••••••••••••••••••••••
Input circuit and frequency conversion ••••.•••••••••••
IF amplifier, detector, and output circuit •••••.•••••.
Automatic 1evel calibration •.••.••••.••••.•••••••••••.
Fast signal detector ••••••••.••••••••.••••••••••••••••
Phase jitter measuring attachment ••••••••••••••••.••••
2-1
2-1
2-2
2-3
2-3
2-3
&
••••
3
2 .1. 5
2.1. 6
2.1. 7
2 .1. 8
2 .1. 9
Phase jitter measuring attachment ••....•..••..••••...• 2-3
Test probe connection ..••.•....••.••..•••••.••.•.••.•. 2-4
Outputs ...................................... ~········· 2-4
Power supply unit ...•...•.•.•..••..••••.•..••••••.••.. 2-5
Frequency tuning ....•....•...•.•.•••..••..•••••......• 2-5
2.2
Synthesizer ............................................ . 2-5
2.3
Control section with microcomputer
COMMISSIONING ................ e••••e••······························ 3-1
3.1
3.1.1
3.1.2
3 .1. 3
3.2
3.3
3.4
3.4.1
3.5
3.6
4
2-8
OPERATION
4.1
4.2
4.3
4.4
4.4.1
4.4.2
4.4.3
4.4.3.1
4.4.3.2
4.4.4
4.5
4.6
Unpacking the unit ············~·······················
Notes for shipping ••••.••••••••.•••.•.••••••••••••••••
Transport in the equipment case TPK-5
or transport case TPG-65 •••••••••••••••.•••••...•.•..•
Use in 19 11 racks ....... " ..............................
3-1
3-2
Installing the unit ••••••••••••••••••.•••.••••.•••.••. 3-3
Connection and switching on ........................... 3-3
Power supplies ....................................... . 3-4
Replacing the fuse •••.•••••••••••••••••••••••••••••••• 3-4
Self-Test •••.••••••••.•.••••••••••••••••••••••••••••.• 3-5
Standard Set-up ....... o.
3-6
$
••
G
••••••••••••••••••••••••••
• e • • • • • e • • • e e • e e e e o • e • • e • o e e • e • • e • • • e e • • • • e e • • • • o • • • e a e •
4-7
Controls on the front and rear sides
4-7
Equipment setting after switching on
4-8
Inputs for measuring •••.••.••••.•••••••.••..•••••••••• 4-8
Tuning the receiver frequency ••••••••••••••••••••••••. 4-8
Digital tuning [12] ••••••••.•••.•••••.•••••••••••••.•• 4-8
Continuous frequency tuning [MAN] •••••.••••••••••••••• 4-9
Incremental frequency tuning ••••••••••••••••••••••••• 4-10
Manu a1 Frequency Stepping ............................ 4-10
Automatic Frequency Stepping ••..•••.•••••••.••••••.•• 4-10
Transferring the frequency setting to the memories
for fSTEP and the sweep limits ••••.•.•.•••••••••••••• 4-11
Automatic level calibration "AUTO CAL" ............... 4-12
Selection of the operating mode analog/digital
"ANLG DGTL
4-13
Di gita 1 1evel measurement ............................ 4-13
Absolute Voltage or Power Level "ABS" ................ 4-14
Level Difference •••..••••••••.••••••••••••••••••••••. 4-14
Reduced Level ••••••.••••••.•••••••••••••••••••••••••• 4-15
Analog level measurement ............................. 4-16
Measuring Range Selection ............................ 4-16
II
4.6.1
4.6.1.1
4.6.1.2
4.6.1.3
4.6.2
4.6.2.1
4.6.2.2
4.6.2.3
4.6.3
4.6.4
3-1
3-1
• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
Scale range ............................................. 4-17
Fast Signal Detector .•.•.•.•••••.••••••••••••••••••.. 4-18
Direction arrows in the level display ••••.•.••••••••• 4-18
Noise averaging "AVRG 11 e~•·••t~-&e••e••e••e>••··········· 4-19
4.7
4.7.1
4.7.2
4.8
4.9
4.9.1
4.9.2
4.10
Bandwidth •••••••.,•••••••"e••••••••••••••••••••••••••• 4-19
Wide-Band section ................................... . 4-19
Selective sect i 0 n
4-20
DetTl()dul ator .......................................... . 4-21
Phase jitter measurements •.•.•.•••.•.••••...•.•.•••.. 4-23
Causes and effects of phase jitter •••••.••.•••••••.•. 4-23
Settings on the Level meter •••.••••••••••••••••••..•• 4-23
Automatic frequency contro 1 "AFC" •.••.••••••••••.•••• 4-24
e •••••••••••••••••••••••••••••••••••
4.11
Track mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.11.1
4.11.2
4.12
4.12.1
4.12.2
4.13
4.13.1
4.13.2
4.13.3
4.13.4
4.14
4.15
4.16
4.17
Applications ••••••••.••••••••••••••••.••••.•••••••••• 4-25
Settings on the level meter •••••••.••••••••••••••.••• 4-26
4.18
4.19
4.20
4.20.1
4.20.1.1
4.20.1.2
4.20.2
4.21
4.22
4.22.1
4.22.2
4.22.3
4.22.4
4.22.5
4.22.6
4.22.7
4.23
4.23.1
4.24
4.24.1
4.24.2
4.24.3
4-2:~
Search .............. ,......... " . . . . . . . . . . . . . . . . . . . . . . . 4-27
Single search (Full range) "SEARCH" •••••••••••••••••• 4-28
Continuous search optimum •••••••••••••••••••••••••..• 4-29
Sweep mde ............... Sl... . . . . . • • • . . . . • . • • . . . . . . . . 4-30
Setting up the sweep limits ••••••••••••••••••••••••••
Sweep sequence and sweep time •••••••.••••••••••••••••
Manual sweep •••••••••••••••••••••••••••••••••••••••••
Display unit connection [42] •••••••••••••••••••••••••
DC (Y-) output [22] ••••••••••••••••••••••••••••••••••
DC (X-) output [231 ••••••••••••••••••••••••••••••••••
10kHz IF output [43] ••••••••••••.••.•••.••••••••.•••
Remote control of the level generators PS-16 and
PSS-16 (Tracking generator output) •••••••.•••••••••.•
Standard frequency input [51] ••••••••••••••••••.•••••
Di gita 1 interface [40 J [41 J ••••••••••••••••••••••••••
Computer control •••••••••••••••••••••••••••••••••••••
Interface Bus IEC 625 •••••••••••••••••••••••••••••.
Interaction between the level meter and the
Interface Bus IEC 625 •••••••••••••••••••••••••••••.
Structure of the Interface Bus IEC 625 Programm ••.•
Bus specification and bus plugs ••••••••••••••••••••••
Printer connection •••••••••••••••••••••••••••••••••••
Metmry functions "MEM" •••••••••••••••••••••••••••••••
Address organization e•••·····························
The functions store and recall ••••••.••••••••••••••..
Storing the fixed frequencies ••••••••••••••••••••••••
Recalling any, single fixed frequencies ••..•••••.••..
Recalling a sequence of fixed frequencies •.••••••••••
Storage of equipment settings (Set-ups) ••••••••••••••
Recall of equipment settings (Set-ups) •••••••••••••.•
Fixed values memory (auxiliary device) BN 874/00.01 ••
Fixed frequencies and equipment set-ups •••.•••••••••.
Measuring accessories ·························~······
Test Probe TK-11 •...•••••••••.••.••••••••.••••••.•.•.
Adapter FEDA-1 (75 Q/50 Q) •••••••••••••••••••••••••••
Reflection and signal balance ratio measurements •••••
4-30
4-31
4-32
4-32
4-33
4-34
4-34
4-34
4-35
4-35
4-35
4-36
4-38
4-39
4-40
4-40
4-41
4-41
4-43
4-44
4-44
4-44
4-45
4-46
4-46
4-47
4-50
4-50
4-51
4-51
4.24.3.1
4.24.4
4.24.5
5
MEASURING NOTES •••••••.••••.••••.••••••••.••••••••••.•••••••••••• 5-l
5.1
5.2
5.3
5.4
5.5
6
Reflection Loss Measuring Adapter RFZ-14 ••••••.•••.•. 4-51
RE0-50 and RE0-56 matching transformers ••••.•••••.••• 4-53
Two-way divider REV -56 •••....•.••••••••••••••••••..•• 4-54
Selectivity curves of the level meter •.•••••.•••.•.•.•
Measurement of high attenuation values .••••••••••••••.
Measurements of impulsive noise and interruptions •.•••
Psophometric weighting of noise voltages ••••••••••••••
Automatic drive level monitoring ••••••••••••.•.•.•••••
5-1
5-3
5-5
5-5
5-7
FUNCTIONAL TESTING, MAINTENANCE, AND MISCELLANEOUS ••••••••••••••• 6-1
6.1
6.1.1
6.1. 2
6.1. 3
6.1. 4
6.2
6.3
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
Functional test when switching on for the first time •• 6-1
Checking the internal noise ••••••••••••••••••.•.•.•••• 6-5
Checking the receiver selectivity •••••••••.••••••••••• 6-5
Functional test of the calibrated attenuator •••••••••• 6-5
Functional test of the test probe connector [18] •••••• 6-6
Functional tests of important modules
(Hardware self-test) •••••••••••••••••••••••••••••••••• 6-6
Maintenance and miscellaneous •.•••••••••••••••••••••• 6-11
Mechanical construction •••••••••••••••••••••••••••••• 6-11
Changing or installing the interface boards •••••••••• 6-13
Installing the EPROM BN 874/00.01 .. ® ............. .. 6-13
Universal conversion system Versacon
9 •.••••.•••••• 6-14
Rechargeable batteries for data retention •••.•.•.•••• 6-14
Figures
2-1
2-2
Simplified block diagram of the Level Meter SPM-16
Simplified block diagram of the synthesizer BN 869
3-1
3-2
3-3
Packing notes •••u••··································· 3-1
Converting the table-top unit for rack installation ••• 3-2
Rear connections on the SPM-16 ••.•••.•.•.••••.•••••.•• 3-4
4-1
4-2
Front view ............................................ 4-1
Rear view •••••e••••••••"••••"e••······················ 4-1
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
Meter scale of the SPM-16 ••••••••••••••••••••••••.•••
Direction arrows in the level display •••••••••••.••••
Dynamic range of the measuring demodulator
Relative Level -50 to +10 dBr •••••••••••••••••••••..•
Receiver tracking ••••••••••••••••••••••••••••••••••••
Configuration and interconnections of the sweep
frequency measuring set-up (rear view) •••••••••••••••
Pin assignments of the Display Unit connector [42] •••
Block diagram of a simple automatic level
measuring system ••••••••••••••••..•••••••••••••••••••
Block diagram of the Interface Bus ¢Ec 625) ••••••.••
2-1
2-7
4-17
4-18
4-21
4-26
4-30
4-33
4-35
4-36
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
5-1
5-2
5-3
5-4
5-5
6-1
6-2
6-3
Pin assignments of the Bus connector on the
Leve 1 Meter •..............•......•.•.•..••.•••.•..•..
Ordering Form No. 5/798 a •.....•..••..•..•..••••••...
Ordering Form No. 5/798 b •..•..••••••••••.•.•••......
Test Probe TK-11 •..•.•••••.••.••••••.••.•.•••••••.•..
Measuring at an impedance of 50 Q .••......•...•......
Connection of the measuring bridge RFZ-14 to the
level measuring set-up •.....••.•..••••••••.••••••••••
Application of RE0-50 and RE0-56 matching transf •.•..
Possible connection using the REV-56
two-way distributor •••••••••.•••.••••••••••••••••••••
Typical selectivity curves for the bandwidths
400Hz, 1.74 kHz, and 3.1 kHz •••••••••••••••.••••••••.
Typical selectivity curve of the Level Meter with
25Hz bandwidth ••.••••••••••••••••••••••.•..•••.•.•.•.
Measurement of High Attenuation Values ••••••••••••••••
Psophometric curve ••••••••.•••••••••••••••••••••••••••
Selectivity curve and effective noise bandwidth •••••••
4-40
4-48
4-49
4-50
4-51
4-52
4-53
4-54
5-1
5-2
5-4
5-6
5-6
Test configuration for the functional test •••••••••••• 6-1
Upper side of the upper folding chassis •••••.••••.••• 6-12
Basic socket Versacon ® 9 with some of the
available Versacon® 9 adaptors ••••••••.••••••••••••• 6-14
Tables
4-1
4-2
4-3
4-4
Controls and Sockets on the Front Panel •••••••••.•..•• 4-3
Controls and Sockets on the Rear •••••••••••••••.•••.•• 4-6
Address Organization • • • . . • • • • • • • • • • • • • • • • • • • • • • • . • • • • 4-42
Program Numbers ........................••.•.........• 4-42
6-1
6-2
Sequence of functional test •••••••••••••.•••.••.•••.•• 6-2
Overview of fault numbers in the SPM-16 •.•••..•••.•••• 6-7
I NT R0 DUC T I 0 N
Although digital cofl1llunication systems are gannnq increasing siqnificance in local and district circuits, carrier frequency systems using
FDM are still the principal means for long distance traffic. level
Measurements play an important part in measuring and checking the
analog characteristics of these systems and the individual sub-assemblies. But modern measuring instruments must be used for new, additional measuring tasks.
Consequently, the Selective Level Meter SPM-16 was designed with
application of the most modern circuit technology and employment of an
internal microcomputer. These provide a high degree of accuracy and
comfort.
Owing to the SPM-16's wide span of frequencies from 10 kHz to 160 MHz
and to its performance characteristics, the Level Meter is as equally
applicable in development, production, installation and maintenance of
analog communication systems of up to 10800 voice channels as it is
for measurements on single sideband radio-link systems. But also the
SPM-16 is suitable for measurements on submarine cable systems and for
investigations on cables carrying digital communications at higher bit
rates (140 Mbit/s). Because of its capability for external control, it
is also applicable in automatic measuring systems.
According to the measuring task, the SPM-16 frequency can be selected
either digitally through a keyboard or continuously in one range, with
1 Hz resolution. For tuning in equal steps of frequency, (e.g. by
channel separation), the frequency may be manually or automatically
stepped. Up to 100 fixed frequencies of frequently repeated measurements can be stored via keyboard entry, to be called out in any
sequence or in consecutive order. Moreover, with an available option,
rmre fixed frequencies can be stored in a user specified Non-volatile
Mermry. A11 the means for setting the frequency make use of an internal synthesizer for attaining high stability and accuracy of the
tuning frequency.
The SPM-16 has a coaxial input at 75 Q input impedance. Test Probe
TK-11 is intended for applications in high impedance (bridging) and
low capacitance measurements. Decoupling Transformers RE0-60 (50 kHz
1
to 14 MHz) and RE0-56 (300 kHz to 60 MHz) permit interaction-free
measurements on system test points. They are transformer-Type attenuators (20 dB) each of which has a loop-trough input and two decoupled
outputs. In selective mode, measurements can be made at levels between
-130 dBm and +20 dBm (-140 and +10 dB): in vvideband mode, between
-50 dBm and +20 dBm (-60 and +10 dB).
Results are indicated on either a digital display, with autoranging
at the highest resolution of 0.01 dB, or an analog meter. When the
analog meter is used, three push buttons, offering selection of three
scale ranges, l dB, 20 dB or 80 dB permit the choice of the best scale
range to fit the appropriate measuring task. The measurement range
setting is accomplished either manually in 1 or 5 dB steps or automatically after a push button has been pressed.
For attaining the highest possible measurement accuracy, the microprocessor adjusts the pre-attenuator and the IF attenuator, taking
into account the overall input level so that the SPM-16 always makes
measurements with the optimum drive signal applied.
Besides absolute level measurements, the SPM-16, in a very simple
way, executes relative level measurements. For that purpose a digital
level measurement is stored as a reference value in a buffer, and each
subsequent measDrement is displayed as either a digital or an analog
value deviating from the reference value. Many measurements made on
communications systems are not given as direct values but instead are
referred to the relative level (dBr) of a test point. To simplify the
evaluation of a measured result in this case, the relative level of
the test point can be adjusted in 0.1 dB steps, and the result can be
readout direct in level expressed as reduced to dBmO (dBO).
The relative level push button can also be used generally for setting
the reference value (e.g. for frequency response measurements).
Various bandwidths are available for adapting to the appropriate
measuring task. Pi lot 1eve l, carrier 1eak, or "hot tones" are measured
with the 25Hz narrow-band filter. Sensitive level measurements are
made with an IF band filter of 400 Hz bandwidth fitted within the
SPM-16. For weighted noise measurements at the CF level in voice channels not carrying traffic, a filter with 1.74 kHz equivalent noise
bandwidth can be switched in.
2
Another position of the bandvli dth svtitch a11 ov-1s 1eve 1 measurements at
the 3.1 kHz channel bandwidth. And also measurable is the noise power
of a 48 kHz wide basic group.
The internal demodulator allows single sideband signals to be presented in upright or inverted position. The converted signal can be
judged for quality either via the incorporated loudspeaker or at the
demodulator output for further processing externally. The demodulator
is especially noteworthy because of its great dynamic range needed for
example with exact measurements of noise or impulsive noise in translated voice channels.
To assess the transmission quality of telephone circuits used for
data communications, phase jitter measurements are performed. Weighting filter and detector characteristic for measuring the peak-to-peak
value conform to CCITT Recom~endation 0.91. The indication appears on
a digital display or on a logarithmic scaled meter in range 0.3· to
30 °.
An automatic level calibration facility eliminates the necessity of
manual calibration and thus assures high measuring accuracy over the
complete frequency range, additionally noticeably decreasing measuring
time, and giving high long-term stability. Therefore, the Level Meter
is suitable for long-term monitoring. The microprocessor control of
the SPM-16, besides the previously mentioned settings of frequency,
permits various other automatic frequency runs. An exceptionally
valuable aid for operating and tuning during the search for spurious
levels or overloading signals is the fast signal detector in conjunction with the automatic search-scan of the tuning frequency. Hereby,
the tuning oscillator is retuned until the incoming signal is at a
level higher than the preselected level threshold and located within
the display range, then the search-scan stops. Simultaneously, an AFC
comes into action and tunes the oscillator exactly to the input signal
frequency. Restart occurs either manually by the actuation of a push
button or automatically after the level and frequency have been printed out. The search-scan rate is matched to the bandwidth selected. The
AFC can also be switched in for all the usual level measurements at
all bandwidths to 3.1 kHz. It has the property of recontrolling the
oscillator over the whole frequency range.
3
End-to-end selective
measurements within interstitial channel gaps
(during the voice channels
are actually carrying
traffic) are possible because of an electronic device functional in operating mode TRACK, whereby
the Level Meter is automatically tuned to the frequency of a generator with
similar signal frequency
co ndit i o ni ng•
l
I<J Generator Section PSS-16
r-----,
I
OP-16
Level Generator PS-16
SPM-16
(Display Unit
I
I SG-2 or SG-3) I
L _____ _j
PSS-16
SPM-16
Selective Level Meter SPM-16 Level Measuring Setup
(Sweep Measuring Setup)
Instruments
and Measuring Setups of the type series 16
If an SG-2, or SG-3 Display Unit is combined with the SPM-16 the combination is a panoramic receiver. Because of the fast switching by the
synthesizer between adjacent frequencies, the entire frequency range,
in a11 operating modes, can be searched without gaps, so that a11
receiver frequencies present within the band can be unambiguously
identified. The sweep circuit incorporated in the SPM-16 is particularly noteworthy because phase hits are not produced. This effect
allows systems under test to have very steep attenuation characteristics and be still measured at correct accuracy. According to application, the two cut-off frequencies or the center frequency and sweep
width can be entered digitally with crystal accuracy. Level Generator
PS-16 or the Generator Section PSS-16 are each suitable for use as a
signal source in the sweep measuring setup.
Many measuring problems may be solved particularly easily if the user
takes advantage of the possibilities for storing the complete menu of
instrument settings and when needed, the stored settings can be called
out. After a push button (addt~ess inquiry) has been depressed, the
SPM-16 correctly sets itself to all measuring conditions preselected
for a definite measuring task. A trickle charged battery is incorporated in the circuitry to hold the stored data in the event of a power
dropout.
4
All functions of the SPM-16 can be controllable by an external IEC
Bus compatible computer if the auxiliary device, the Interface Bus
<rEC 625) Card 1 ), has been fitted.
Other controllable peripheral equipment such as Level Generator, Test
Point Selector, external storage system can be added-on to configure a
powerful Automatic Level Measuring Setup for use in test departments
and FDM surveillance systems. A suitable Test Point Selector (100 MHz)
is the MU-7 or the RAS-1 with Interface Card. Instead of the Interface
Bus <rEC 625) Card a printer interface for the V. 24/V. 28 interface
could be used for printing out the measured results arranged in
various printed formats (SPM-16 commencing with Series B). Another
measurement accessory is the Return Loss Measurement Bridge RFZ-14.
This device permits the measurement of frequency variant return loss
in the frequency range 100 kHz to 100 MHz. Impedance matching networks, 75 Q/50 Q, are available for measurements on modules and
systems that have 50 Q characteristic impedance.
Despite the multiplicity of functions, the SPM-16 has been assembled
in an enclosure of low height. Connection-, setting-, and displayfield are arranged for easy viewing and operation on an ergonomically
designed front panel. Light emitting diodes placed above or next to
the operator's push buttons show the functions with which the operator
is involved at the time. The SPM-16 is available either as a bench
rndel or as suitable for mounting in a 19" rack. Covers are available
for the SPM-16 front and back panels' protection against dust and
water spray during transport or storage.
I) Connection to IEEE-Bus (I-EEE 488) by adapter p1ug S 834
5
1
S PECI F
C A T I 0 NS
1.1
FREQUENCY
1.1.1
FREQUENCY RANGE
FOR SELECTIVE AND WIDE-BAND MEASUREMENTS •••••••••.• 10kHz to 160 MHz
1.1. 2
FREQUENCY DISPLAY ••.•••.•••....••.••••.•• digital, 9-decade, with LCD
Resolution ....................................................... 1Hz
1.1.3
FREQUENCY TUNING
Digital with keyboard,
in frequency steps with direction keys, input of the step increment
with keyboard,
quasi-continuously with handwheel over the complete frequency range,
switchable between coarse and fine tuning
Sma 11 est frequency step, di gita 1 • . • . • • • • • • • • • • • • . • • • • • • • • • . . • . • • 1 Hz
continuous, fine •••••••..••••••••••••.• 1Hz
coarse •••.••••.•••••••••••.••..•••••• 100Hz
1.1.4
AUTOMATIC FREQUENCY SEQUENCES
1.1.4.1
Frequency Search
over the whole frequency range with stop by signal detector and automatic fine tuning to the detected signal with AFC, search speed matched
to the bandwidth:
1.1.4.2
Bandwidth
3.1 kHz
1. 74 kHz
Search speed
1
250
~1Hz/s
kHz/s
400 Hz
20 kHz/s
25 Hz
200 Hz/s
Auto Step
Automatic stepping of the tuned frequency in increments between preset
frequency limits.
1-1
Increments and frequency limits entered by keyboard,
Stepping speed adjustable •••..•..••••.••...•• 0.1; 0.3; 1;
1.1.4.3
... '
300 s
Trackina
Automatic switching of the tuned frequency between preset frequency
limits by a frequency instrument as soon as the level indication disappears, input of the increment and frequency limits by the keyboard.
1.1.4.4
Sweep Frequency Operation
Sweep limits are set with the keyboard by entering either the start
and stop frequency or the center frequency and the deviation.
Sweep sequence: periodic (triangular) or single sweep
Sweep duration adjustable •••••••••.••••••••••• 0.1; 0.3; 1 ••. ; 300 s
Additional facility •••••.•••• manual sweep and continuous search with
optimum search speed as specified
in section 1.1.4.1
1.1.5
AUTOMATIC FREQUENCY CONTROL (AFC)
The capture range corresponds to the nominal bandwidth of the selected
bandwidth filter as specified in section 1.4.1 (switched off in the
case of 48 kHz). The locking range corresponds to the frequency range
specified in section 1.1.1.
1.1.6
ERROR LIMITS 0F THE TUNED FREQUENCY •••••••.••••••.•.•.•••• ! 1 · 10 -7
The above error limits are valid for the rated ranges of operation of
influence quantities listed in section 1.9, including aging in the
first year.
1.2
LEVEL
1.2.1
MEASURED PARAMETERS
Absolute level
as power level (dBm), refered to 1 mW or
as voltage level (dB), refer to 0.7746 V
1-2
Differential level (dB) between an absolute level and a stored reference
level. Any absolute level can be stored as a reference level by depressing a pushbutton.
Reduced 1eve 1 ( dBmO or dBO)
1.2.2
RESULT INDICATION, RESOLUTION, RANGE SELECTION
1.2.2.1
Result Indication 1 ), switchable •••••••••••••••••••• digital or analog
Digital display ••••••••••••••••••••••••••• LCD with 5 digits and sign
Analog display ••••••• Analog meter with switchable ranges and digital
display of the level value for 0 dB meter reading.
Ranges of the meter:
1 dB scale
20 dB scale
80 dB scale
1.2.2.2
•••••a•~t••••••••
• • • • • • • • • • a • • • • •
................
-1.5 to +0.3 dB
-20
-80
to +2
to +0
dB
dB
Resolution
Selective mode, indication averaging on •••••••••••••••••••••• 0.01 dB
indication averaging off •••••••••••••••••••••• 0.1 dB
Wide-band mode
0.1 dB
Levels which cause wide variations of the indication, for example due
to superimposed interference signals or to insufficient separation from
the intrinsic noise, are displayed with a resolution of 0.1 dB, even if
indication averaging is switched on.
1.2.2.3
Range Selection
For digital display:
1
Automatic with overload checking of the wideband section during selective measurements.
) Noise signals such as the loading level of CF systems actually
carrying traffic, thermal noise, or intermodulation noise result,
due to the rectifier characteristic, in practically the same reading as a sinusoidal signal with the same RMS value. Crest factor:
12 dB.
1-3
For analog display:
Single automatic cycle by depression of a pushbutton with overload checking of the wide-band
section for selective measurement or manually
with the range switch in 1 dB or 5 dB steps,
depending on the selected range of the meter.
In addition to remote control (BN 853/02):
Adjustment of the measurement range in 1 dB steps, with the choise of
the wide-band drive signal from 3 modes: low noise, normal, low
distortion
Dynamic range in the selected range ••••••••••••••••••••.••••• + 10 dB
(over- and underloading are indicated)
For very fast measurements, the short averaging feature permits a
measurement to be made even when the receive section has not fully
settled.
1.2.3
MEASURING RANGES
1.2.3.1
Absolute Level:
1.2.3.2
Input
Selective mode
dBm
dB
Wide-band mode
dBm
dB
Coax. 75 Q
-130 to +20
-50 to +20
-140 to +10
-60 to +10
Reduced Level
According to the range of the absolute level specified in 1.2.3.1 for
relative level (resolution 0.1 dB): •.••••••••••••• -99.9 to +20.0 dBr
1.2.4
AUTOMATIC LEVEL CALIBRATION
Automatic level calibration is carried out every two minutes and whenever a parameter change could cause an error in the level indication.
In selective mode, the frequency of the calibration signal tracks the
tuning of the receiver; in wide-band mode, the calibration frequency is
fixed at 10 MHz.
For measurements in which the measuring sequence could be disturbed by
insertion of a calibration cycle, as during sweep frequency measurements, the automatic level calibration can be switched off.
1-4
When in external control, the SPM-16 can be calibrated as "single
shot". (Auxiliary device BN 853/02).
1.2.5
BASIC INTERFERENCE
1.2.5.1
Intrinsic Noise Level (maximum value) when the measuring input is terminated by Z = 75 Q:
Bandwidth
Intrinsic noise level/dBm (dB)
25 Hz
-121 (-130)
-130 (-139)
400 Hz
-109 ( -118)
-126 ( -135)
1. 74 kHz
-102 (-111)
-120 (-129)
3.1 kHz
-100 ( -109)
-118 (-127)
48 kHz
-104 ( -113)
10 kHz
1.2.5.2
50 kHz
300 kHz
160 MHz
Level of interference lines
Synchronous (tracking as receiver is tuned) ••••• ~ -130 dBm (-139 dB)
Tunable (not tracking as receiver is tuned) •.•••• ~ -127 dBm (-136 dB)
1.2.6
FAST SIGNAL DETECTOR FOR RAPID SIGNAL IDENTIFICATION, ACTIVE ONLY WITH
ANALOG DISPLAY
The threshold referred to 0-dB meter reading
on the 1 dB scale •••••..•••••.••••••••••••••••• approximately -1.2 dB
on the 20 dB scale •••••••••••••••••••••••••••••• approximately -15 dB
on the 80 dB scale (for search only) •••••••••••• approximately -40 dB
1.2.7
ERRORS OF THE LEVEL INDICATION
Unless otherwise stated, the specified error limits are valid for the
rated range of use shown in section 1.9, with automatic level calibration on. with the input supplied from a source with an internal impedance Z. Level errors caused by the reflection coefficient of the input
impedance are thus included in the error limits.
1-5
1.2.7.1
Errors in Selective Mode
Error limits with digital display, or with analog indication with
indication averaging (1-dB-scale) for bandwidths 25 Hz to 3.1 kHz under
inclusion of the basic interference given in para. 1.2.5.
Level
+20 dBm (+10 dB)
I
l
+10 dBm (O dB)
0
Error 1imits/dB
+0.4
-+0.9
+0.3
-+0.8
-
I
dBm (-10 dB)
-
+0.25
-
+0.35
-
-70 dBm (-80 dB)
-100 dBm (-110 dB
)L-----__J
10 kHz
-+0.6
50 kHz
+0.7
-
110 MHz
160 MHz
Additional errors to those values shown in the table:
with 48kHz bandwidth (level ~ -70 dBm/-80 dB) ••••••••••• +0.5 dB
with an analog reading: 20 dB scale (-5 to +2 dB) •••••••• +0.2 dB
80 dB scale •••••••••••••••••••••••• +2 dB
For short averaging (only with auxiliary device BN 853/02) •••
~0.4
dB
For digital display with switched off indication averaging, the tabulated values raise by the roundin9 off error of the decreased resolution
according to para. 1.2.2.2.
For attenuation measurements at the same frequency (level difference
from two measurements, whereby the first measut~ement serves for the
reference level), the tabulated values are also valid if the reference
level is located in range -60 dBm to 0 dBm (-70 to -10 dB).
1.2.7.2
Variation of level reading \'lith frequency, Selective Mode
Error limits
Referred to f
1-6
=
10 MHz, in level range -60 to 0 dBm (-70 to -10 dB)
Automatic calibration, switched off
I
10 kHz
1.2.7.3
1 _:1:0.25 dB
:<:0.35 dB
300 kHz
I
+0.6 dB
+0.35 dB
60 MHz
110 MHz
I
160 MHz
Error in Wideband Mode
Error 1imits \'lith digital display
I
+2 dB
+1 dB
10 kHz
110 MHz
Error additional to tabulated values
with analog reading, 20 dB scale (-5 to +2 dB)
1.3
160 MHz
+0.2 dB
PHASE JITTER
The weighting filter and the rectifier characteristic for measurement
of phase jitter (peak-to-peak value) comply with CCITT recommendation
0. 91.
For measurements with the test tone 1020 ~ 10 Hz in the speech channel
or in a CF channel, the receiver must be tuned to the center of the
channel; otherwise, it is tuned to the test signal frequency.
1.3.1
MEASURING RANGE
Phase jitter is indicated digitally or on the analog meter
Indication range •••••••••••••••••••••••••••••••••••••••••• 0.3 to 30"
Resolution of the digital display •••••••••••••••••••••••••• Max. 0.1·
1.3.2
ERROR LIMITS OF THE INDICATION
at 150 Hz jitter frequency and signal level
~ -60 dBm (-70 dB) •••••••.•.••••••••••••••••••••••••••••• +10% +0.5"
(The most favorable level range is automatically selected and an error
is indicated if the signal level is too low).
1-7
1.4
SELECTIVITY AND HARMONIC RATIO
l. 4.1
SELECTIVITY, SWITCHABLE: 25 Hz/400 Hz/1.74 kHz/3.1 kHz/48kHz
Effective Noise Bandwidth
I
Attenuation value with separation
from midfrequency of filter
Hz 1 ) +2 kHz 1 )
Bandwidth -+70 Hz
-+250
25 Hz
25 dB
~
-+15 kHz
60 dB
400 Hz
~
55 dB
~
60 dB
1. 74 kHz
~
50 dB
:;;
54 dB
?:
63 dB
3.1 kHz
~
45 dB
>
50 dB
?;
60 dB
48 kHz 2 )
1.4.2
~
+5
- kHz
~
70 dB
approx. 50 dB when separated by -+35 kHz
IMAGE FREQUENCY REJECTION AND IF SUPPRESSION ••••••••••••••••• : 70 dB
Intermediate Frequencies at •••.•••••••••••.•• 220 MHz, 40 MHz, 10kHz
Image frequencies at ••••••• f. + 440 MHz, f. - 80 MHz, f. +20kHz
1n
l. 4. 3
1n
1n
DISTORTION PRODUCTS
for basic frequency level ~ +10 dBm (0 dB) and digital measurement mode
or analog with manual range selection and ~ 40 dB sensitivity above the
measuring range of the basic frequency level (authenticate with bandwidth 25 Hz).
1.4.3.1
Harmonic Distortion Products aK 2 and aK 3 for
Load in the frequency range ~ 4 MHz •••••••••••.••••••••••••••
< 4 MHz ..••••••.••.•.•••••.••.•••
1)
2)
1-8
~
~
65 dB
60 dB
10 dB lower va1ues valid for frequencies > 110 MHz
The specified filter characteristics are achieved by sweeping the
tuned frequency over a 48 kHz band and integrating the input signal
spectrum which falls within this band.
1.4.3.2
Non-harmonic Distortion Products
< llO
for load in frequency range
>
1.4.4
,. 75 dB
MHz
~
110 MHz
55 d!3
NOISE POWER RATIO NPR •••••...••••••••••••••••••••.••••• approx. 45 dB
when loaded with a noise band signal of 4 to 60 MHz.
Wide-band level -25 to +10 dBm, measuring bandwidth 1.74 kHz and
digital measurement mode.
1.5
MEASUREMENT PERIODS
The following specifications are guide line values, with which the
measurement periods are sufficiently described for practical measurements.
1.5.1
LEVEL MEASUREMENTS WITH AUTORANGING, AUTOMATIC CALIBRATOR SWITCHED OFF
25 Hz 1 ) 400 Hz 1 ) 1.74 kHz 1 ) 3.1 kHz 1 ) Wideband
Band\'li dth
Averaging: normal (OFF) 0.6 s
long (ON)
1.5.2
1.8 s
0.4 s
0.4 s
0.4 s
0.4 s
1.5 s
1.5 s
1.5 s
0.4 s
LEVEL MEASUREMENT WITH ADJUSTMENT OF THE MEASURING RANGE AND THE WIDEBAND DRIVE SIGNAL VIA AN IEC-BUS. (Auxiliary device BN 853/02).
Automatic calibration switched OFF:
Bandwidth
short 2 )
Averaging: normal (OFF)
long (ON)
1)
2)
25 Hz
400 Hz
1. 74 kHz
3.1 kHz
48 kHz
100 ms
20 ms
20 ms
20 ms
350 ms
500 ms
150 ms
150 ms
150 ms
350 ms
1.5 s
1.5 s
1.5 s
1.5 s
350 ms
The specified measurement periods are valid for levels with ~40 dB
separation from the signal loading level. With separation> 40 dB,
the values are lengthened through the linearity check by
1 s + 300 ms/5 dB.
measured with not completely settled receive section (see para.
1.2.7.1)
1-9
\
1.5.3
LENGTHENING OF THE MEASUREMENT PERIODS WHEN AUTOMATIC CALIBRATOR IS
SWITCHED ON:
(The bracketed values are for input level ~ -10 dBm/dB)
Bandwidth
25 Hz 400 Hz/1.74 kHz/3.1 kHz 48 kHz
norma 1 (OFF)
Averaging:
long (ON)
1s
100 ms
s
600 ms
1
300 ms
---
WIDEBAND
600 ms
600 ms
1.5.4
PHASE JITTER MEASUREMENT: ••••••••••••••••••.••••••••••••••••••••
1.5.5
DATA TRANSFER, TRANSFER TIME PER CHARACTER
1.6
INPUT FOR MEASURING
······•oo•••••••••o•••
0
3 s
1 ms
Co axi a1 •••••••••••••••••••••••••••• o •••••• o o ••••• System Versacon ® 9
Input impedance - ................................................. 75
Return loss .......•..........................••......•.•.•...
Tolerable input level (AC and DC components) •••••.•
Discrete spurious output signals
1.7
ADDITIONAL INPUTS AND OUTPUTS
1.7.1
INPUT FOR EXTERNAL STANDARD FREQUENCY
~
~
~1
30 dB
+25 dBm (16 dB)
Input connector ••••••••••••••
Versacon ® 9 conversion system
Frequencies •••••••••••••••••••••••.•••••••••••••••• 1, 2, 5 or 10 MHz
o •• o •••••
Necessary level ····························~·········· -10 to +10 dBm
Input impedance ... " ........•... D...... . . . . . . . . . . . . . . . . . . . . . . . . . . 75 (~
1.7.2
OUTPUT FOR STANDARD FREQUENCY
Output connector ..••..••••••
o •••••••••
Versacon ® 9 conversion system
Frequency ••.•••••.•••••••••••• ~ ••••••••••••••..••••.••••.•.••• 10 MHz
Output level into 75 Q load ••••.••••••••••••••••••••• 0 dBm +2/-4 dBm
1-10
1. 7. 3
INPUT FOR CONTROL FREQUENCY
For control of the Receive Section through the synthesizer
Input connector •..•••....... Versacon ® 9 conversion system, floating
Frequency range ••••..••.•..•••••..•••...•••••••.•.•••• 220 to 380 MHz
Level into 75Q load •.•.•••••.••.•••••••••.•••••••••••••. (+3.:!:_2) dBm
1. 7. 4
IF OUTPUT
Output connector
Versacon ® 9 conversion system
Output frequency when tuned to
center of band •••••••••••••••••••••••••••••••.•••.•••••••• 10 kHz
Output level proportional to meter reading,
Level for 0-dB indication into 600 Q
1oad ..................... "
-10 dB
................................ .
1. 7. 5
Y-OJTPUT VOLTAGE (DC) •••••••••••••••••••••••••••• 3-pole CF connector
DC output voltage proportional to meter reading,
open circuit voltage for full scale deflection •••••••••••••••••• +5 V
Output impedance
5 kQ
................................................
1. 7. 6
X-OUTPUT VOLTAGE (DC) ••••••.••••••••••••••••••••• 3-pole CF connector
DC output voltage proportional to frequency
within the start and stop frequency limits,
Open circuit voltage: at start frequency •••••••••••••••••••••• -2.5 V
at stop frequency ••••••••••••••••••••••• +2.5 V
Output impedance ••••••••••••••.._.. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 5 kQ
l. 7. 7
DEMODULATOR OUTPUT •••••••••••••••••••••••••••••••••• 3-pole CF socket
Built-in loudspeaker with adjustable volume.
Single sideband demodulation, switchable to upright or inverted
position, frequency position of converted channel
when tuned to center of channel ••••••••••••••••••••••••••• 0 to 4kHz
Frequency response in the range 0.6 to
3.4 kHz, referred to 2kHz .•••••••••••••••••••••••••••••••• +1 dB
Output level proportional to meter reading
1-11
Level for 0-dB-indication into 600 Q
loac1 ......... ., ....................................... approx. 0 dl3
Psophornetricall.Y weighted intrinsic noise at the demodulator output,
for Transmission Level Point (TLP) settings in the range -50 to +10 dBr,
at f ~100kHz, •••••••••••••••••••••••••••••••••••••••••• -65 dBm
Intrinsic phase jitter (in accordance with CCITT
recot11n1endation 0.91) •....... e.
1.7.8
5
••••••
•••••••••••••••••••••••••
~
o.s·
DISPLAY UNIT CONNECTION SOCKET
for X, Y, and reference trace voltages. Control input for switching the
meter for display of the reference trace voltage of the display unit. A
TTL signal for control of the pen lift of an X-Y plotter is also
available (series B and later).
1. 7. 9
INTERFACE BUS (IEC 625) (with auxiliary device BN 853/02)
for control of all SPM-16 functions through an external computer.
1. 7.10
DIGITAL INTERFACE
for control of two additional units.
1.7.11
POWER SUPPLY CONNECTION FOR TEST PROBE TK-11 ••••• short-circuit proof
with automatic compensation for pass-band attenuation of ••••••• 10 dB
1. 7.12
TRACKING GENERATOR OUTPUT
'
®
Output connector •••••••••••••••••••••• Versacon
9 conversion system
for controlling the PSS-16 Send Section or
as fixed level output, level into Z = 75 Q •••••.•••••••••••.• -15 dBm
1.8
MEMORIES FOR FIXED FREQUENCIES AND SPM-16 SETTINGS
1.8.1
NUMBER OF FIXED FREQUENCIES
freely prograrrrnable
1)
..........
5
..............
preprogrammed (Auxiliary device BN 874/00.01)
.....................
100
100
1) Maintenance of stored data in the case
of a.c. dropout •••••••••••••••••••••••••••••••••••••• approx. 30 days
1-12
The fixed frequencies can be advanced automatically by one step per
address step as described in sections 1.1.4.2 and 1.1.4.3.
1.8.2
NUMBER OF EQUIPMENT SETTINGS
freely progralllllabl e
1)
••••••..•••••••..•••••••••.•••••••••••••••••• 11
preprogrammed (auxiliary device BN 874/00.01) ••••••••••••••••••••• 40
1.9
POWER SUPPLIES AND AMBIENT CONDITIONS
All error limits specified in the preceeding specifications are applicable for the following rated ranges of use of the influence quantities, unless otherwise specified.
1.9.1
POWER SUPPLIES
A.C. line voltage range without switching,
rated range of use
··························e·•··········
96 to 261 V
A.C. line frequency, rated range of use •••••••••••••••• 47.5 to 63Hz
Current consumption I rms ••••••••••••••••••••••••••••••• approx. 1.5 A
Power consumption •••••••.••••••••••••••••••••••••••••••• approx. 65 W
Protection class in accordance with
IEC 348 and VDE 0411 ••••••••••••••••••••••••••••••••••••••••••• I
Warming up time •••••••••••••••••••••••••••••••••••••••••••••
1. 9. 2
~
15 min
OPERATING CLIMATE
Permissible ambient temperature
· l opera t 1ng
·
range •••••••••••••••••••••••••••••••••• +5 to -40"C
Nom1na
Storage and transport range •••••••••.••••.•••••••••••••• -40 to +70"C
Radio frequency interference
in accordance with VFg. 526/1979 of
suppression
the Federal German Post Office
1) Maintenance of stored data in the case
of a.c. dropout •••••••••••••••••••••••••••••••••••••• approx. 30 days
1-13
1.10
DIMENSIONS, WEIGHT
Weight •.•••..••...•.••••.•..•••.•••••••.•.•...•.••••.•. approx. 22 kg
Overall dimensions without cover (w x h x d in mm):
Table-top unit •..•••.••.•.••••••••••••••••.•...•.•.•• 477
19" chassis (DIN 41 494)
443
19
11
X
X
244
220
432
X 377
(5 units)
X
conversion kit ······•••••e•••······················· BN 700/00.05
1.11
AUXILIARY DEVICES
1.11.1
EPROM, ORDER NO. BN 874/00.01
Storage of 100 fixed frequencies and menu of 40 instrument settings in
a non-volatile memry, according to users own needs.
(Request Ordering Form No 5/798 a, b)
1.11.2
INTERFACE BUS <IEC 625) CARD BN 853/02
for control of all unit functions.
1.11.3
PRINTER INTERFACE, BN 905/02
Applicable in SPM-16 corrmencing with Series B, instead of <rEC-625)
Interface. For the connection of a printer with a V.24/V.28 Interface
with printout of measurement mode, measurement parameters, and measured
results.
1.12
MEASURING ACCESSORIES
1.12.1
TEST PROBE TK-11, ACTIVE TEST PROBE (SERIES 0 ••• )
Frequency range
2 kHz to 160 MHz
Input 1eve 1
Maximum permissible AC voltage •••••••••••••••• 1 V or +10 dBm (+2 dB)
Maximum superimposed DC voltage ••••••••••••••••••••••••••••••••• 50 V
Attenuation when terminated with R.
1
and 20 DC ••••••••••••••
5
=
R
a
=
•••••••••••••••••••••••••••••••
(with automatic gain correction in SPM-16).
1-14
75 Q at 100 kHz
10 dB +0.1 dB
Affects of ambient temperature on attenuation
within the rated range of use ••••.•.••••••••••.•...•..••••. ;::' 0.05 dB
Frequency response, referred to 100 kHz:
Input impedance: up to f = 25 MHz
up to f = 100 MHz
up to f = 160 MHz
to 100 MHz
up to 160 MHz
up
............
............
•
Cl
••••••••••
Intrinsic harmonic ratio for input levels
~
;:§
0.2 dB
approx. 0.2 dB
approx. 50 kQ 113.5 pF 1 )
approx. 5 kQ II 3. 5 pF 1 )
approx. 2 kQII3.5 pF 1 )
0 dB
.........
ak2
ak3
60 dB, ak3
1::
~
40 dB,
50 dB
70 dB
!!:
-20 dB ••••••••••••••••••• ak 2 ~
Power supplies ••••••••••••••••••••••••••••••••••••••••••• from SPM-16
for input
levels~
......
Permissible ambient temperature
Rated range of use ••••••••••••••••••••••••••.••••••••••.. +5 to +4o· c
Storage and transport range ••••••••••••••••••••••••••••. -40 to +70"C
Standard accessories:
Connection to unit being tested ••••••••••••••••• Test prod and ground
clamp \'lith prod
Receiver connection •••••••••••••••••••••• Element of the Versacon ® 9
Conversion system (pin contact)
Optional accessories:
Versacon ® 9 adaptor: S 222
Elements of the Versacon® 9 conversion system
Weight ••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 150 g
Dimensions, in rrm, \'lith test prod •••••••••••••••••••••• 11 dia. x 105
1.12.2
REFLECTION FACTOR MEASURING BRIDGE RFZ-14
Frequency range •••••••••••••••••••••••.•••••••.••• 100kHz to 100 MHz
Rated impedance .................................................. 75 Q
Insertion loss with Z connection open •••••••••••••••••• approx. 8 dB
X
Frequency response in the range 300 kHz to 60 MHz •••• approx. ~0.5 dB
Reference impedance •.••.•••••••••.•.••.••••••••••••••••••••• Built-in
1) The capacitance is valid for TK-11 without conversion to
Versacon ® 9.
1-15
Error limits after calibration, with plug connector BNC, TNC or 1,6/10
300 kHz to 60 MHz ••.•••.•••.••., ••••••.••••••.•.•••.••• 0.007 +0.10 r 2
2
100kHz to 100 MHz .•.•.•••••••.•••••••••.•.••..•...••• 0.015 +0.13 r
Permissible input power •••.•...••••••••••••••••••••••••..•.•••• 0.5 W
Connections for transmitter and receiver ••••••.••••• Universal socket
Versacon ® 9
Connections to unit being tested ••••••• Uni versa 1 socket Versacon ® 9
Optional connections ••.••••.••.••.• BNC; TNC; 1,6/5, 6; 2,5/6; 1,6/10
Weight ••••••••.•••••••••••••••••••••••••••••••••••••••••••••••• 200 g
Dimensions, w x h x d in mm, without connections •••••••• 54 x 33 x 27
1.12.3
ADAPTER FEDA-1 (75 Q/50 Q)
The data are valid for the adapter without connecting elements at an
ambient temperature of 23"C ! 5"C.
Impedances •••••••••••••••••••••••••••••••••••••••••••••••••• 75 Qj5{J.;l
Frequency range
·•e······································
0 to 100 MHz
Attenuation •••.•.•••.•.•••••••. "' ••••••.••.••••••••••••••.• " .••.• 6 dB
Error limits of attenuation ••..•••••••••••••••••.••••••••••• + 0.1 dB
Reflection factor ••••••••••••••••••••••••••••••••••••••••••••• ~ 0.01
Maximum load •••••••••••..•••••..••••••••••••••••.••••••••••.••. ;:; 1 W
Maximum permissible ambient temperature at rated load ••••• 0 to +45"C
Storage temperature ••••••.•••••••••••••••••••••••••••• -55"C to +60"C
Socket adapters
75 Q side •••.•••.•••••••• 2, 5/6 (F) or 1, 6/10 (M/F) or BNC (M/F) or
N-connector (M/F)
50 Q side ••••••••••••••••••••••••••••• BNC (M/F) or N-connector (M/F)
Wei ght ................................ ~~ • • • • • • . • • • • • • • • • • • • • • • • • • • • 50 g
Dimensions vlithout adapters, 1 x d in mm
•••••••••••••••
It • • • • •
Abbreviations: (t"l) =male connector; (F) =female connector.
1-16
47
X
16
1.12.4
RE0-50/RE0-56 MATCHING TRANSFORMER
Frequency range
RE0-56 .••••.....•....•..•••.••.•.••••••.•.•••...•.. 300kHz to 60 MHz
RE0-50 ••••..•.•.•••.•••..••..•.•..•..••••.•.•.•.•••• 50 kHz to 14 MHz
Input
Loop-through of useful signal, characteristic impedance ••••.•••• 75 Q
Outputs
Splitting the test signal for two test connectors,
output impedance
.................................................
75 Q
Return loss
Return loss of loop (both measuring connectors loaded with 75 Q):
RE0-50 •.•••••••••••.••.••.•••••••••••••••.••••••••••••••••••.•• 26 dB
RE0-56 • • • • • . • • . • • • • . • • . • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • • • . • • • • • • • 20 dB
Insertion loss of the through-loop (both measuring connectors loaded
with 75 Q): RE0-50 •••.•••.••••••••••••••••••••.•.•••••. 0.25 + 0.1 dB
O 25 + 0.4 dB
RE0-56
•
-0.1 dB
......................................
1.12.5
TWO-WAY SPLITTER REV-56
Frequency range •••••••••••.••.•.••••••••.•••.••••••• 6 kHz to 200 MHz
Input
Input impedance .........................•..........•....•....... 75 Q
Outputs
Signal splitting to 2 test connectors, output impedance ••••••••• 75 Q
Loss with 75 Q termination ••.•.••••••••••.•••••.•••••••••••.••• 10 dB
Error limits of attenuation in ranges:
6kHz to 100 MHz ••..••••.•••••••••••••••••••••••••••••••• +0.2 dB
100 MHz to 200 MHz (with Series B) •••••••••.••••• approx. +0.3 dB
Return loss in ranges:
6kHz to 100 MHz •••.••••••••••••••••••••••••••••••••••••• ~ 30 dB
,.
100 MHz to 200 MHz (with Series B) •••••••••••••••.•••••••
25 dB
1-17
1.13
ORDERING INFORMATION
Level meter SPM-16
+
Auxiliary device (at extra cost)
EPROM, Storage of fixed frequencies and instrument
settings in a non-valible memory 1 )
Interface Bus Card (IEC 625)
with adapter plug IEC 625/IEE 488 (S 834)
Alternatively:
Printer Interface V.24/V.28
Measuring accessories (at extra cost)
Test Probe TK-11 (with test prod)
Versacon ® 9 adapter
Reflection factor measuring bridge RFZ-14
Test Point Selector MU-7
IEC-Bus-Interface For MU-7
Matching Transformer RE0-56+
REU-50+
Two-way Splitter REV-56+
Adapter FEDA-1 (75 Q/50 Q)
Display unit SG-2 (screen size 85 mrn x 120 mm)
Display unit SG-3 (screen size 150 mm x 210 mm)
Display unit inserts
see
Printer Trend 800 RO 8
Connection cable for (IEC 625) interface bus
120 em long
200 em long
19" convers·ion kit for SPM-16
Front and rear covers for SPM-16 (1 set)
Equipment case TPK-5
Transport case TPG-65
BN 874/01
BN 874/00.01
BN 853/02
BN 905/02
BN 573/00
s 222
BN 830/00.01
BN 590/00
BN 590/00.01
BN 839/00.01
BN 839/00.02
BN 839/00.03
BN 319/00
BN 429/00
BN 593/00
SG-2/SG-3
++
K 343
K 344
BN 700/00.05
SD-5
BN 626/11
BN 621/65
+)
Equipped with the basic 75 Q socket Versacon®9 and with BNC
element. Other elements must be specified when ordering the
equipment - see data sheet for Versacon ® 9.
1) The required fixed frequencies and equipment settings must be specified with ordering form No. 5/798 a, b.
++) See data sheet TREND 800 RO for ordering details and data.
1-18
INFORMATION SUBJECT TO CHANGE WITHOUT PRIOR NOTICE
RE~~ARKS
TO THE ERRORS SPECIFIED IN THIS OPERATING MANUAL
Re t u r n
Lo s s
I mp e d a n c e
The effect introduced by the return loss of the receiver input or the generator output is included in
the error specified for the level reading of a receiver or the output level of a generator.
Moreover, the specified error takes into account
that a level meter is operated as "terminated" (input impedance= source impedance= Z ). This is
also valid for a level generator (ou~put impedance=
load impedance Z0 ).
Br i d g
r a t i o
The specifications given for the input or output balance are provided by the methods defined in CCITT
Recommendation 0. 121.
This same Recommendation states that:
"The signal balance ratio is an overall measurement
of the symmetry of a device and includes the influence of the impedance balance ratio as well as the
influence of unwanted longitudinal voltages produced
by a generator or the influence of the common-mode
rejection ratio of a receiver."
r~
Lo s s
i n g
b a 1 a n c e
A receiver operated in the "high impedance"
(bridging) mode introduces a level error due to the
finite input impedance. The error's maximum value
when measured at a testpoint of source impedance Z/2
is expressed as aB, the bridging loss.
Zo
describe the degree of balance of a device (generJtor or receiver) under operational conditions in
most cases it is sufficient to measure and specify
the s i g n a l
b a 1 a n c e
r a t i o l)nly.
Thus, the specifications in this Operating hannual
are provided by measurement of s i g n a 1
b a 1 a n c e
r a t i o • This is done through
emploment of an accurately center-tapped inductor
with both of the tightly-coupled half windings being
completely symmetrical. Each half represents Z/2.
Me a s u r e m e n t
o f
gnal
Balance
S
Generator
a
Center-tapped inductor-
-
+
Zo
Ge n e r a t o r
Ratio
z
b
1.. t V2
4
'C
TV1
l
__L
Zo
...!,.
Generator signal balance ratio is defined as:
aB
The bridging loss is defined as follows:
Bridging loss aB
L2 - L1
aB = 20 1g
I
+
~
zzion
Me a s u r e m e n t
gnal
S
Therefore, the bridging loss is the level difference
caused by the high impedance level meter input
bridging a system terffiinated with Z •
0
~
I ~: I [dB]
o f
Balance
Re c e v e r
Ratio
I
a
c Z/4
In every case, Z.1n
20 log
Z , which results in:
o
[dB]
?
...,Receiver
I
.!.
z
z!:
1
b
V1
J
0
/V2
;---
I
Ge;nerator
Voltage
reading bet wee n
a and b
.J,.
Receiver signal balance ratio is defined as:
For that reason, the specified value of aR 1 related to the value Z (e.g. 600 Ohms) can b~·~asily
recalculated to yi~ld the value of aB 2 for the
value z2 (e.g. 900 Ohms):
'
aB,l •
!:;,_
z1
aB = 20 log
I ~: I [dB]
The dotted impedance, Z, is the input impedance of
the device under test. If the input impedance is a
high value, then this impedance must be externally
connected in the parallel.
2
T E C HNI CA L DE T A I L S
The Selective Transmission Measuring Set SPM-16 with the wide-band
section comprises mainly the modules: receiver section, synthesizer,
and control section; the latter section includes the microcomputer and
the control and display panel. The signal processing and the various
modules are described in detail below (See Figure 2-1).
X-output
'10MHz
J--------< Standard frequency
J--------c:: 1; 2; 5; 10 MHZ
Output >--~--1
(to PSS-16) ,
10 kHz to 160 MHz
.----+---r==--:.:.c.==o..:.:=...-----<U, 220 to 380 MHz
..--------<
1
IF output
Input
10 kHz to 160 MHz ,
Figure 2-1
Simplified block
~iagram
of the Level Meter SPM-16
2.1
RECEIVER SECTION
2 .1.1
INPUT CIRCUIT AND FREQUENCY CONVERSION
The Level Meter operates on the triple superhet principal. In order
to achieve good decoupling between the measuring circuit and the chassis ground for measurement of high losses on two port networks (see
section 5.2), the input circuit is decoupled, for high frequency purposes, by a coaxial choke.
The input signal passes from the coaxial input to the remote controllable Calibrated Attenuator (FED-2, BN 802/2) and then to the preamplifier. For wide-band level measurements, the measuring signal is
2-1
connected to a quasi-rms rectifier, converted to 10kHz, and injected
into the IF signal path. Here, it is rectified and displayed. For
selective level measurements, the wide-band detector acts as a level
monitor for optimum matching of the loading signal (at the level meter
input) to the input circuit and the first mixer. The input attenuator
and the IF attenuator are so adjusted by the microcomputer that the
best possible measuring accuracy is always achieved. This makes manual
"low noi se/lo\'1 distortion" switching superf1 uous.
The preamplifier is followed by a further attenuator which permits the
optimum matching of the mixer to the wide-band load and the switching
of the measuring range in 5 dB steps. The low-pass input fi1ter suppresses all spurious and image frequencies which lie above the reception band. The receive frequencies are converted to the first intermediate frequency of 220 MHz in the first mixer, using the 220.01 to
380 MHz conversion signal from the synthesizer. The second IF is
40 MHz. This is applied to the 40 MHz crystal band-pass filter which
permits direct conversion to the last IF of 10 kHz by the third mixer.
The necessary carrier signal for this is produced in a phase-locking
oscillator, synchronized to the reference frequency in the synthesizer. The selectivity of the Level Meter is determined by the flat
3.1 kHz wide 10 kHz band-pass filter. Various filters with differing
noise bandwidths can be connected after this point according to the
application.
2.1. 2
IF AMPLIFIER, DETECTOR, AND OUTPUT CIRCUIT
The converted received signal passes through a stage for power level
matching, according to the selected measuring conditions, either to a
logarithmizing circuit with a level range of 80 dB or to the switchable IF amplifier, whose gain can be switched in 1 dB steps with extremely precise transformer-type attenuators. The maxi mum overa 11 gain
is 89.9 dB. This module also contains the calibration attenuator for
level calibration (see section 2.1.3). Signal detection is carried out
in a true rms detector. The crest factor of the detector circuit is
12 dB. The detected measured vo1tage either is amplified and connected to the meter for analog display or passes through an analog-digital converter for digital level display.
2-2
2.1. 3
AUTOMATIC LEVEL CALIBRATION
In order to achieve the high measuring accuracy, the SPM-16 is
equipped with an automatic level calibration circuit which is automatically switched on at preset intervals or if the equipment settings
(e.g. bandwidth, frequency) are changed. The calibration frequency is
tuned along with the measured frequency in order to achieve a very low
intrinsic frequency response. The extremely precise and temperature
constant calibration level is produced in the calibration generator.
The calibration frequency is obtained by conversion of the modified
control frequency and the fixed, multiplied standard frequency from
the synthesizer (see section 2.2).
2 .1.4
FAST SIGNAL DETECTOR
A signal voltage at the input to the unit, and which lies within the
indication range of the analog meter is indicated, with the aid of a
fast signal detector, by illumination of an LED. For this purpose, the
10 kHz IF voltage is compared with a reference voltage which corresponds to a level threshold of approximately -15 dB or approximately
-1.2 dB on the meter scale. If this threshold is exceeded by the IF
voltage, 10 kHz pulses trigger a monoflop, with an active time of
approx. 1 s, and this causes the LED to illuminate. During frequency
search operations, the signal detector is used to stop the search.
When operating in logarithmic mode, the LED is continuously illuminated; however, search operation is possible at a level threshold of
-40 dB as indicated on the instrument.
2 .1. 5
PHASE JITTER MEASURING ATTACHMENT
For measurement of the phase jitter, the IF signal is connected to a
phase comparator, where it is compared with the ·average phase position
of a low jitter reference oscillator signal that has a slow restoration control characteristic.
The measured voltage, which is proportional to the phase, is connected via a weighting filter which includes all jitter components in the
frequency range ~(20 to 300 Hz) to the peak-to-peak rectifier, and is
then logarithmized amplified, and displayed. The weighting filter and
the rectifier characteristic comply with CCITT recorrmendation 0.91.
2-3
2.1. 6
TEST PROBE CONNECTION
For high impedance (bridging), unbalanced measurements, the active
Test Probe TK-11 is provided. This has the function of an impedance
transformer with an input capacitance of only 3.5 pF when a test prod
is used. It receives its power supply from the Level Meter. The insertion loss of 10 dB is automatically compensated in the SPM-16 when the
TK-11 is connected.
2 .1. 7
OUTPUTS
Several outputs are available for further processing of the converted
received signal.
In analog mode, a single sideband demodulator permits reconversion of
any voice channel from the CF plane to the audio frequency band.
Conversion is carried out with the aid of a switchable carrier signal
of 8 or 12 kHz for the upright or inverted position. This carrier is
derived from the standard frequency. For a reproduction true to the
original~ therefore, the tuning must be to midchannel. The demodulated
received signal can be either connected to the built-in loudspeaker
for qualitative assessment or extracted at the demodulator output for
further external processing (e.g. connection of interruption or impulsive noise counters). The demodulator is characterised by low intrinsic noise of about 65 dB below the meter reading of 0 dB, thus permitting correct conversion of a CF channel.
The last intermediate frequency of 10 kHz can be extracted at the decoupled output which follows the IF amplifier.
The Level Meter has a fixed-level output for delivering the Generator
Signal to the level conditioning in the Generator Section of the
PSS-16. This output can also be used as a source of generated signal
(tracking generator) for frequency response measurements.
For connection of a plotter or similar device, the Level Meter has a
Y-output at which a DC voltage proportional to the meter indication is
available.
An X-output supplies a DC voltage which is proportional to the frequency within the adjustable limits fSTART and fSTOP"
At two other outputs, the variable carrier frequency and the standard
frequency can be extracted for the external tuning of a level genera-
2-4
tor. An input for application of an external standard frequency of 1,
2, 5 or 10 MHz permits substitution for the internal standard frequency.
2.1.8
POWER SUPPLY UNIT
The Level Meter is equipped with a switching power supply unit which
permits connections to a.c. line voltage in the range 96 to 261 V
without further switching. It is characterized by a high efficiency,
which results in low internal heating in spite of the compact construction.
This provides higher reliability of the Level Meter.
A built-in rechargeable battery buffers all of the existing memory
modules if the a.c. line voltage fails or if the unit is switched
off, thus maintaining all stored data and settings.
2.1.9
FREQUENCY TUNING
Frequency tuning is carried out digitally, in BCD code, in all operating modes. For quasi-continuous frequency tuning over a continuous
range, a small DC generator (tache-generator) is driven by the tuning
knob and a subsequent voltage-frequency converter generates setting
pulses for the internal counters. The frequency information is transferred to the frequency display and the synthesizer via display buffers.
2.2
SYNTHESIZER
The control frequency of 220.01 to 380 MHz necessary for tuning the
Level Meter, and the fixed frequencies necessary for synchronization
are generated in a synthesizer (BN 869) with the following characteristics:
- High frequency accuracy and stability
- High spectral purity (very high adjacent channel rejection and
high signal-to-noise ratio)
Phase continuity when the frequency is changed
- Quick settability
- Compact construction.
2-5
The construction and the most important modules are shown in the extremely simplified block diagram of the synthesizer in Figure 2-2.
The control frequency fT (220.01 to 380 MHz) is
tage control1ed oscillator which is adjusted so
quency is precisely the sum of the frequency fR
lator and the frequency fi of the interpolation
generated in a volthat the control freof the locked osciloscillator.
The locked oscillator operates in the frequency range 219.8 to
379.7 MHz, and can be tuned in 100kHz steps by another phase lock
loop. For this purpose, the oscillator frequency is divided down to
100 kHz in a programmable locked divider and compared with the standard frequency in a zero phase controller.
Interpolation within the 100 kHz steps is carried out in a single interpolation loop. This operates with fractional division ratios, thus
it permits fl~equency settings with values after the decimal point
[1].
This configuration permits short settling times, even with small step
increments.
The interpolation oscillator runs at a relatively high frequency between 40 and 60 MHz in order to permit, in the following 200 : 1 divider, reduction of the phase hits resulting from the phase lock loop.
As the interpolation frequency should be adjustable in steps of 1 Hz,
the 200 : 1 divider means that the interpolation divider must be adjustable in 200 Hz steps. In ordE!r to permit rapid reprogranming, the
output frequency of the interpolation divider is 100 kHz. This is compared with the divided standard frequency in the phase meter. Frequency settings in 1 Hz to 1 kHz positions would divide into fractional values and result in phase hits. For this reason, a compensation
voltage with the same shape as the interference voltage, but with
opposite polarity, is superimposed on the output signal from the phase
meter.
Further measures, such as synchronous transfer of frequency setting
information into the locking and interpolation dividers or the block[lj
2-6
P. Harzer: "Frequency Synthesis in fvtodern Level Measuring Setups"
translated from original NTZ publication, Volume 33 (1980), No. 2,
pp. 90-94
ing of the carrier loop during the so-called interpolation exchange,
'permit maximum suppression of the spurious frequencies in the control
signal.
The 100 kHz reference frequency and further synchronization frequencies are generated in the time base. This comprises mainly the standard frequency oscillator and the 10 MHz crystal controlled oscillator, with a low proportion of spurious frequencies and locked in a
rigid phase to the reference frequency via the standard frequency synchronization. The standard frequency oscillator, which can also be replaced by an external frequency standard of 1, 2, 5, or 10 MHz, is
thermostatically controlled to achieve the high accuracy of
1
X
10- 7 •
Fixed frequency 10 MHz
r--;-ta:d:d---------"-;m:-~.:-1 r~;;n;l;;;;;----~-
r~~:n.:~':';
:
I
10 MHz
~
c
cp '---
G
~00 I I
,4; &:! f---.,._
U-!,..
G :
,4; &:: I
I
T
1 S/10MHz
(>;C.
I
1
T ""'V
10MHz
I
:J
'-
I iI 1
I
1
I
I
1
;:~::~~yf--
1,2,3,10MHz
-l
-- 1 I --locking osc.
I I
219.8 to379.7 MHz
Synchron.
1
-
d,
~
f
R
I
___i__L_
-.----.-,
N
I
1
I
I
I
11
Carner esc.
1
v /n
i
.______
1-
d,
~
f
T
frequency
220.01 to380MHz
'
f )
I T = •R + I
(f
I
I
I
1
1
1
200 to Joo kHz
(fr - FR)
C{J
:I
n
I
I
~Control
220.01 to380MHz
I
I
I
1
rc7rr::~o; - - -~- - ,
1
I
1
;r:~·u:~cn:ard
I J
I
I
L - - - - - - - - - - - - - f - - - J L _________ J L __________ _j
100kHz
200 to 300kHz
r - Divide~it'hf~;;:;:.,:;r---- -~~rpalatTa~5;;-:- - ,....__L__
Frequency
{
informoHon
(BCD code)
0 to 159.9 MHz
~
I
I
I
0 to 99.999 kHz
20
:
divisil)n ratio
40 to 60 MHz
~~ r------
In
T
, __
,----
-;:,./,
~
f1
n, m
---,
J
L___ ~
,--200
I
I
I
1
1
:
I
Interpolation loop
I
M
L-----------------------J~
Figure 2-2
Simplified block diagram of the synthesizer BN 869
2-7
2.3
CONTROL SECTION WITH MICROCOMPUTER
The microcomputer comprises the central processing unit (CPU) - a
type 8085 microprocessor - the program memory (ROM), the working memory (RAM), and the input and output gates. The displays and controls on
the front panel are connected to the microcomputer via data and control lines. The keyboard of the control panel is used, amongst other
things, for entry of fixed frequencies and of complete equipment settings into the RAM (Random Access Memory). Battery buffering of the
RAM power supplies is provided to maintain the stored data in the case
of an a.c. power dropout.
If required, an additional customer-specific EPROM can be fitted for
fixed frequencies and equipment settings. A results log can be produced on an external printer connected via a printer interface for
V.24/V.28 interfaces (SPM-16, commencing ~lith series B). Instead of
the printer interface, an IEC interface can be fitted for connection
of an external computer. Remote control facilities exist for all functions of the SPM-16.
After power is switched on, an automatic RAM/ROM self test is executed. Functional testing of the most important modules can also be initiated by the operator. In the case of a fault, the test sequence is
stopped and the fault number is displayed.
2-8
3
C 0 MM I S S I 0 N I N G
3.1
UNPACKING THE UNIT
The SPM-16 is shipped in a special packing case which was subjected to
comprehensive stress testing at Wandel & Goltermann.
This case guarantees that the test equipment will arrive without damage, even under rough transport conditions. The unit should be removed
carefully from the appropriate side of the packing case. It is recommended that the orginal packing materials be retained for possible future shipment. If this is not done, please read the following notes.
3 .1.1
NOTES FOR SHIPPING
Safe transportation of the SPM-16 is guaranteed only by correctly
designed packing materials. If the original packing case has been
lost, we recommend that the unit be packed as shown in Figure 3-1.
Wooden board
16 mm thick
Hard padding fixed
to the unit by means
of adhesive tope
60mm
560mm
Folding carton
,____ _ _ _ 600mm
------<~-1
h = height
Firgure 3-1
3 .I. 2
Packing notes
TRANSPORT IN THE EQUIPMENT CASE TPK-5 OR TRANSPORT CASE TPG-65
The equipment case TPK-5 protects the SPM-16 against dust and mechanical damage for light transport operations (e.g. in a motor vehicle).
It also provided suitable protection against splash water. Further
protection of the inclined front panel is provided by placing the rear
cover SD-5 on the front of the SPM-16 before putting the unit into the
3-1
case. For increased climatic and mechanical stresses (e.g. rail or air
transport), the transp01At case TPG-65 is recommended, as this protects
the equipment against extreme effects.
3.1. 3
USE IN 19" RACKS
The case dimensions of the SPM-16 are matched to DIN Standard 41 494
or American Standard ASA C 83.9 "Racks and front panels ... The SPM-16
is thus suitable for installation in 19 racks; it is only necessary
to modify the front panel dimensions by fitting two mounting brackets
as shown in Figure 3-2. The complete 19 11 conversion kit including
mounting screws, is available under order No. BN 700/00.05.
The feet on the bottom of the unit and the guide studs on the top of
the unit must be removed before installation (see also Figure 3-2).
11
'!l'------
Foot---
Hinged support - -
L
~
~J
Figure 3-2
19" mounting bracket
Converting the table-top unit for rack installation
Caution: When installing the unit in equipment cabinets, care must be
taken that the upper limit of the rated range of use for the ambient
temperature is not exceeded (see section 3.2). Generally, the following measures are necessary:
A space of one height unit (44.4 mm) must remain free between the
units.
3-2
If necessary, fans must be fitted to extract the heat produced in the
cabinet. Suitable filters should be provided to prevent accumulation
of dust on the units.
3.2
INSTALLING THE UNIT
The Level Meter SPM-16 can be used at ambient temperatures between
+5 and +40"C. If used within larger systems or if installed in racks,
care must be taken that this temperature range is not exceeded. (e.g.
by spacing the various units as mentioned in section 3.1.3).
Temperatures between -40 and +70"C are permissible for storage or
transport. In such cases, it is recommended that the displays and controls are protected by the Transport Protection Cover SD-5 (see section 1.13, ordering information) on the front and back of the unit;
these prevent mechanical damage and protect against dust and splash
water.
The angled front panel makes the unit easy and comfortable to use. In
addition, the Level Meter can be installed at an angle by swinging
down the supports attached to the front feet. The SPM-16 will also
operate reliably in this position.
The liquid crystal displays for frequencies and levels decrease the
current needed, and consequently the internal heating of the unit. No
fan is necessary and a higher reliability is achieved. When the unit
is put in place, the ambient light should be bright because then the
displays are particularly easy to read.
3.3
CONNECTION AND SWITCHING ON
Before switching on, connect the control output ~ of the oscillator section to the control input ~ of the receive section using the
included short BNC cable (K 336) as shown in Figure 3-3. (Longer connection cables should not be used).
3-3
0
K336
0
..,....-+-~/
0
0
45
0
0
52
PQ
Figure 3-3
3.4
Rear connections on the SPM-16
POWER SUPPLIES
The Level meter is supplied with power by a switching power supply
unit which is installed on the right side wall of the SPM-16. It can
be operated from AC voltages between 96 and 261 V without additional
switching, the a.c. line frequency lying between 47.5 and 63 Hz.
The enclosed a.c.power cord should be used for connection to the a.c.
lines. The Level Meter complies with protection class I of VDE 0411,
i.e. the case and the ground socket are connected to the protective
conductor. If a different a.c. power cord is used, ensure that a protective conductor is included and connected.
After inserting the a.c.power cord in the a.c. socket Q (see Figure
4-2) on the rear of the unit, insert the plug into the a.c. outlet
socket and switch on the Level Meter with the a.c. power switch H on
the front (by depressing the pushbutton). The specified error limits
are valid only after a warming up period of 15 minutes.
3.4.1
REPLACING THE FUSE
If, after the Level Meter SPM-16 has been switched on, there is neither a level nor a frequency display ond none of the indicator lamps
are lit, first unscrew the fuse holder P on the rear of the unit and
check the fuse.
The replacement fuse should be type T 3, 15 A (3.15 A, slow-blow);
two spare fuses are included with the unit.
3-4
3.5
SELF-TEST
When the Level Meter is switched on, an automatic RAM/ROM test is executed to check the functions of the RAM and the system software (ROM).
If the test is executed successfully, the symbols 0----- appear momentarily on the frequency display, followed by the last parameters for
frequency and level values stored in the unit. In the case of an error
in the control section. an error number is di sp 1 ayed in the frequency
display. The digits in the level display (address in hexadecimal code)
contain further information for localization of the fault.
Example:
,_,--,-,,_
1-1
I II
Frequency display
Level display
The meanings of the symbols and digits are explained in Table 6-2.
A functional test of the most important modules (internal hardware
test) can be initiated by entering the address No. 9003 (in Series A
the address number 9001 should be pressed before 9003). No external
connections are necessary for this purpose as the internal calibration
signal is used as a signal source.
The self-test ought to be executed after a waiting time of a few minutes.
Sequence:
Depress the following pushbuttons:
[MEM]
9001
[RCL]
[MEMJ
9003
[RCL 1
(in Series A only)
If the test is successful, the symbols 1----- appear in the frequency
display. In the case of a fault, a fault number (e.g. 1--003) appears
in the frequency display; the meanings of these numbers are explained
in Table 6-2. The unit can be switched back from the test programm to
the measuring program by again entering 9001 [RCLJ. After that, the
Standard Set-up appears again (see para. 3.6).
3-5
3.6
STANDARD SET-UP
All equipment set-ups are stored in a semiconductor memory which is
supplied with voltage from a rechargeable accumulator when the a.c.
power is switched off. For this reason, the last equipment set-up
which was stored always appears when the unit is switched on again.
Stored fixed frequencies are also retained when the power is switched
off.
If the unit is switched off for a longer period, however, it is possible that the buffer battery is exhausted and that the stored information is lost. In this case, the following standard set-up is automatically selected when the power is switched on again:
f
= 100.000
kHz
fSTEP = 1.000 kHz
Bandwidth 3.1 kHz
Mode: ABS, ANLG, 20 dB scale
Measuring range: 0 dB
Di sp 1ay "S\~EEP OR STEP TIME"
=
1 s
It may be necessary to disconnect the buffer battery during repair
work, which also results in loss of the stored data. In order to obtain the defined initial state, the pushbutton [TJ (see Figure 6-2)
should be depressed after the unit has been switched on again; this
pushbutton is accessible on the control p.c. board after the upper
case cover has been removed. Depression of the pushbutton again loads
the standard set-up in the meoory. (See also the note in section
4.22.1).
If a fault occurs during operation, switch the unit off and on again
to call out the RAM/ROM test. The test is executed automatically as
described above. After this, the hardware test can be executed as described previously.
If neither of the tests results in a fault indication, although there
is a fault in the unit, it is recommended to carry out a reset by calling out program number 9000 before resuming measurements. The program
is initiated by depressing the following pushbuttons:
[MEMJ
3-6
9000
[RCLJ
Note: This reset clears a11 stored fixed frequencies (address range 0
to 99); the stored front panel settings (address range 100 to 110) are
replaced by a standard set-up as described in section 3.6 (see also
the note
Important Safety instructions
This instrument left the manufacturer in perfectly safe operational condition. To maintain this condition and resulting
safety for the operator the following precautions ought to be carefully noted.
A. C. power line voltage
Opening the Instrument
The operating voltage of the instrument should be the same as
the a. c. line voltage, so check whether or not the two voltages
are equal.
After the covers have been removed or when components are
removed with tools, certain components that operate with
applied voltage could be exposed. And also connection points
might be carrying a voltage.
Therefore, before the instrument is opened for inspection, all
voltage sources should be disconnected.
But sometimes calibration, maintenance or repairs require that
the instrument be open and operating with applied voltage. So
only experienced craftspersons who understand the dangers
associated with working on instruments that have exposed
voltage points should undertake the job.
Capacitors can retain a voltage charge even after the instrument has been disconnected from voltage sources. Thus. the
circuit diagrams should be observed.
Safety Class
This instrument is categorized as Safety Class I according to
VDE 0411 or IEC Publ. 348. The power cord delivered with the
equipment has a protective ground conductor. The a.c. power
plug must be plugged into an a.c. power receptacle that has a
third wire to ground, except in rooms that are particularly
certified otherwise. Any disconnection of the protective grouncl
conductor either inside or outside of the instrument is not permitted.
Connection to measuring circuits presenting
hazards to personnel
Before the connection is made to a hazardous circuit, a
protective ground connection, for protection against the measurement circuit, ought to be connected to the enclosure. In
case the protective ground conductor of the a.c. power line
can also assume this protective function. the a.c. power connection should be established first of all. If the measuring
circuit has an inherent protective ground conductor, then this
conductor must be connected to the enclosure before a connection is made to the measuring circuit.
Repairs, Replacement of Components
Repairs must be done according to correct technical practice.
With that, particular attention must be paid to the characteristics of construction. None of the safety precautions should
be changed, especially for leakage paths and air gaps, and
separation by insulation must not be reduced.
Only original replacement parts ought to be used. Other
replacement parts are only permitted if the safety and protection
against human injury are not degraded through the use of nonoriginal components.
Safety Testing after Repair and Maintenance
Defects and Exceptional Conditions
When 11 can be assumed that safe operation is no longer possible. the equipment should be taken out of service and
inadvertent operation should be prevented.
This occurs when
- the equipment shows external signs of damage
- the equipment no longer operates
- after being overstressed in any way (e.g. storage, transport)
so that the tolerable limits are exceeded.
Fuses
Only specified fuses are permitted for use.
Testing of the protective ground conductor in the
power cord for the instrument:
The resistance of the protective ground conductor shall be
measured. It should be <0.5 ~2. The power cord should be
bent and kinked during the measurement so as to reveal any
intermittent connection. This gives evidence of a defective
power cord.
Testing the insulation of the a.c. power circuit:
The insulation resistance is measured at 500 V between the
a .c. power connection and the protective ground conductor
connection. For this measurement, the instrument's power
switch should be ON.
The insulation resistance ought to be >2 MQ.
5.81
Important Safety instructions
This instrument left the manufacturer in perfectly safe operational condition. To maintain this condition and resulting
safety for the operator the following precautions ought to be carefully noted.
A. C. power line voltage
Opening the Instrument
The operating voltage of the instrument should be the same as
the a. c. line voltage, so check whether or not the two voltages
are equal.
After the covers have been removed or when components are
removed with tools, certain components that operate with
applied voltage could be exposed. And also connection points
might be carrying a voltage.
Therefore, before the instrument is opened for inspection, all
voltage sources should be disconnected.
But sometimes calibration, maintenance or repairs require that
the instrument be open and operating with applied voltage. So
only experienced craftspersons who understand the dangers
associated with working on instruments that have exposed
voltage points should undertake the job.
Capacitors can retain a voltage charge even after the instrument has been disconnected from voltage sources. Thus. the
circuit diagrams should be observed.
Safety Class
This instrument is categorized as Safety Class I according to
VDE 0411 or IEC Publ. 348. The power cord delivered with the
equipment has a protective ground conductor. The a.c. power
plug must be plugged into an a.c. power receptacle that has a
third wire to ground, except in rooms that are particularly
certified otherwise. Any disconnection of the protective grouncl
conductor either inside or outside of the instrument is not permitted.
Connection to measuring circuits presenting
hazards to personnel
Before the connection is made to a hazardous circuit, a
protective ground connection, for protection against the measurement circuit, ought to be connected to the enclosure. In
case the protective ground conductor of the a.c. power line
can also assume this protective function. the a.c. power connection should be established first of all. If the measuring
circuit has an inherent protective ground conductor, then this
conductor must be connected to the enclosure before a connection is made to the measuring circuit.
Repairs, Replacement of Components
Repairs must be done according to correct technical practice.
With that, particular attention must be paid to the characteristics of construction. None of the safety precautions should
be changed, especially for leakage paths and air gaps, and
separation by insulation must not be reduced.
Only original replacement parts ought to be used. Other
replacement parts are only permitted if the safety and protection
against human injury are not degraded through the use of nonoriginal components.
Safety Testing after Repair and Maintenance
Defects and Exceptional Conditions
When 11 can be assumed that safe operation is no longer possible. the equipment should be taken out of service and
inadvertent operation should be prevented.
This occurs when
- the equipment shows external signs of damage
- the equipment no longer operates
- after being overstressed in any way (e.g. storage, transport)
so that the tolerable limits are exceeded.
Fuses
Only specified fuses are permitted for use.
Testing of the protective ground conductor in the
power cord for the instrument:
The resistance of the protective ground conductor shall be
measured. It should be <0.5 ~2. The power cord should be
bent and kinked during the measurement so as to reveal any
intermittent connection. This gives evidence of a defective
power cord.
Testing the insulation of the a.c. power circuit:
The insulation resistance is measured at 500 V between the
a .c. power connection and the protective ground conductor
connection. For this measurement, the instrument's power
switch should be ON.
The insulation resistance ought to be >2 MQ.
5.81
.·.'.il
}~,
Table 4-1
Controls and Sockets on the Front Panel
(see Figure 4-1)
Contra l
number
Designation
Fu n c t
in the circuit diagrarrm
o n
20
s
10
[2 J
20
s
42
Pushbutton for switching to manual mode
during remote control or for manual initiation of printer operation
[3 J
20
7
20
s
s
4
20
s
5
20
20
s
s
8
9
Pushbuttons for display of: Absolute level in dB or dBm.
Stored reference level in dB or dBm, level input by simultaneous depression of
the pushbuttons "ABS" and "REF".
Level difference between absolute level
and reference level in dB.
Level expressed in dBm or dBmO.
Relative level in dBr, level input by
depressing bushbutton twice.
[4]
20
20
s
s
3/
1
Selection of operating modes analog or
di gita 1
[5]
20
18
Automatic frequency control
[6 J
20
s
s
12
Memory pushbutton; used together with the
pushbuttons "STO" and "RCL" for storage
and recall of fixed frequencies or equipment settings.
[7]
20
s 19 ••. 24
[l]
f7uml
~
Calibration pushbutton; automatic level
calibration can be switched off.
Control panel for input and display of
single frequency ("f"), frequency step
11
11
(
f
STEP ) • and sweep limits
11
(
II
fSTART
11
'
"fsTOP" or "fCENT
11
'
Llf").
[8 J
20
s
2
Pushbutton for automatic setting of the
measuring range in analog mode with input
signal connected.
[9]
22
s
1
Measuring range switch in analog mode,
switching in 1 or 5 dB steps, depending
on setting of [10].
4-3
il
,,.
Control
number
Designation
in the ci r.+ d.1agrarrrn
cu~c.
I'I
1
1
I
l..,-
F u n c t
o n
EJ
[10]
20
s
14 ••• 16
( 20 dB )
B
[11]
[12
20
s
6
[14]
s
s
;r
i,
Changeover switch for fast or slow dis-
31. •• 41
43 ••• 47
18 Mo 1
Decimal keyboard for measuring parameter
input:
Multi-function keys for frequency, relative level (brown) and memory function
(blue), clear key "CLR".
Knob for continuous frequency tuning together with the pushbutton MAN" •
11
[16]
20
s
11
Selection of bandwidth, demodulator, or
phase jitter measurement.
[17]
20
s
17
Selection of the deflection time for
sweep frequency operation or the dwell
time in AUTO STEP mode, of manual svteep,
or periodic search (OPT).
[18 J
2 Bu 7
Power supply for TK-11 probe
[19 J
2 Bu 4
Coaxial input, 10 kHz to 160 MHz
[20 J
17 p 1
Volume control for built-in loudspeaker.
[21 J
17 Bu 1
Demodulator output.
[22 J
16 Bu 2
Y-output voltage (DC)
[23 J
18 Bu 1
X-output voltage (DC), voltage proportion a1 to frequency vJith in L1 f.
A
22 JC 1
Digita1 display of level, or phase jitter
in digital mode.
B
16 J 1
Meter for level and phase jitter display
in analog mode.
c
19 GL 2
Signal detector.
4-4
iL
play.
J
20
20
Selection of the required scale range
in analog mode.
I--
Control
number
Designation
in the circui t di agrarm1
Fu n c t
o n
Digital display of frequency.
Address; test and fault numbers are displayed here for self-test or memory
operation.
D
19 JC 2
E
20
s 30
Pushbutton for frequency resolution
100 Hz (coarse) or 10 Hz (fine) during
continuous tuning.
F
20
s 25/27
Direction pushbuttons for frequency
search operation.
G
20 S 26/S 28
H
1
I
1 Bu 2
K
20
s
29
Pushbutton for all automatic frequency
stepping with step increment 11 f
.. or
for "TRACKING".
STEP
L
20
s
44'
Direction pushbuttons for manual frequency stepping with step increment
s
1
s 47
Pushbutton of periodic or single sweep.
Mains Sivitch
Ground socket
llf
II
STEP •
4-5
Table 4-2
Controls and Sockets on the Rear
(see Figure 4-2)
Control
number
Designation
in the circuit di agrarrrn
[ 40 J [ 41 J 21 Bu 1 , 2
Fu n c t i o n
Digital interface for control of two external devices
[42]
16 Bu 1
Connection socket for Display Unit SG-2 or SG-3
[43]
15 Bu 3
Intermediate frequency (IF) output, 10 kHz.
[44]
10 Bu 2
Generator output, 10 kHz to 60 MHz for controlling
the PSS-16 Generator Section
[45 J
4 Bu 1
Control frequency input, 220 to 380 MHz, to be connected to [52].
[46 J
21
[50]
63 Bu 1
Standard frequency output, 10 MHz.
[51]
65 Bu 1
Input for external standard frequencies 1, 2, 5 or
10 MHz.
[52]
58 Bu 1
Control frequency output, 220 to 380 MHz, to be connected to [45].
M
21@)
Installation position for the Interface Bus (IEC 625)
Coard or printer interface
s
2
dB/dBm changeover switch.
N
Battery compartment for Ni-Cd cells needed for data
retention
0
Allen wrench for removal of the case
p
1 Si 1
AC power fuse
Q
1 St 1
AC power connector
R
4-6
Rating plate
4
0 P E RAT I 0 N
4.1
CONTROLS ON THE FRONT AAND REAR SIDES
The front panel of the Level Meter SPM-16 is divided into the three
functional panels: connection panel, control panel, and display panel.
Most of the parameters necessary for measurement are selected with
pushbuttons on the inclined part of the front panel, which simplifies
operation and provides the unit with a modern design. On the left half
of the control panel are configured the pushbuttons for selecting the
required measuring mode, level display, and scalej while on the right
half of the front panel are configured the pushbuttons for frequency
tuning.
Each pushbutton has an LED which lights when the function is active.
Some of the pushbuttons have double or triple functions (MHz, kHz
pushbuttons), which are clearly identified by different colored markings or by a second LED.
The rear side of the SPM-16, on which the division of the level meter
into control sections, level measuring sections, and synthesizer is
visible, contains the connection sockets for analog and digital control signals, the installation position for the Interface Bus
0Ec 625) Card, and power supply elements.
The abbreviations used in the operating instructions for controls and
sockets are shown in Figures 4-1 and 4-2, which are on fold-out pages
for ease of use.
The relationships between the abbreviations (normally numbers within
boxes) and the circuit diagrams in the appendix are described in Tables 4-1 and 4-2.
The abbreviations used in the circuit diagrams have the following
meaning (for example, 20 S 10): the switch (calibration pushbutton)
can be found in circuit diagram 20 and is designated S 10.
The numbers within boxes in the tables are the same as the numbers
printed on the front and rear sides of the Level Meter. The table also
provides a short summary of the functions of the various components
and sockets. All coaxial connection sockets are universal sockets
which can easily be converted to the most comnon socket types used in
telecommunications technology (see section 6.3.4).
4-7
4.2
EQUIPMENT SETTING AFTER SWITCHING ON
After the commissioning and switching on as described in chapter 3,
the SPM-16 automatically sets itself to the parameters and operating
roodes used for the last measurement before it \'las switched off. If the
built-in buffer battery needed for the retention of data in the CMOSRAM is exhausted or if it was disconnected from the memories during
repair work, a different setting appears. The capacity of the fully
charged battery is sufficient to retain the memory data for approximately 30 days with the power switched off.
4.3
INPUTS FOR MEASURING
The Level Meter is equipped with a 75 Q coaxial input, [19]. Test
Probe TK-11 is intended for high impedance (bridging), low capacitance
measurements (see para. 4.24.1).
Caution: Input [19] must be protected from the application of d.c.
and levels greater than +25 dBm or +16 dB. The max. applied voltage
must not be higher than 4.8 V (AC and DC components) because the thin
film technology resistors in the input voltage divider could be destroyed.
4.4
TUNING THE RECEIVER FREQUENCY
Frequency tuning is carried out, according to the task, either digitally with the keyboard, continuously, or automatically. (AUTO STEP,
TRACK, SEARCH).
The use of a synthesizer, which is characterized by very low spurious
frequency and noise levels and by phase continuity when the frequency
is changed, achieves both high accuracy and high stability of the selected frequency in all operating modes. The frequency accuracy of the
SPM-16 is ~1 x 10- 7 of the displayed frequency value. These error
limits include the temperature response in the rated range of use and
the aging errors which occur within one year.
4.4.1
DIGITAL TUNING [12]
The required receiver frequency is entered in MHz or kHz with the aid
of the keyboard [12 ]. (The LED above the blue pushbutton 11 MEM" must be
off).
4-8
Example:
f = 0.950 kHz
0
95
"kHz"
Leading and trailing (1Hz to 100Hz positions) zeros may be omitted.
The synthesizer is tuned to the new value only when the [MHz] or [kHz]
pushbutton is depressed (ENTER function).
If an incorrect digit is entered during frequency selection, the display can be cleared with the aid of the clear key [CLRJ and the required frequency reentered. Tuning of the synthesizer is not affected
by this. The digits are shifted from right to left in the display.
A new frequency is entered by overwriting the old value.
The tuned frequency is displayed with a maximum of nine digits in display window D, with a resolution of 1 Hz. The frequency is always displayed in kHz.
4.4.2
CONTINUOUS FREQUENCY TUNING
[MAN]
If the precise value of the frequency to be measured is not known and
if it is necessary to tune for maximum level indication (in analog
JT()de), the continuous tuning function can be svtitched on by depressing
the pushbutton [MAN] in functional panel [13].
Frequency tuning is carried out in a pseudo-continuous mode, i.e. in
steps of 1 Hz or 100 Hz:
if the pushbutton [MAN] is depressed once, with 1 Hz resolution
(FINE)
if the pushbutton [MAN] is depressed twice, with 100 Hz resolution
(COARSE).
Due to the phase continuity of the synthesizer, no phase shifts occur
during continuous tuning, which means that no additional sideband
spectrum is generated.
After selecting the required resolution 11 COarse or fine", the receiver
can be tuned over the whole frequency range with knob [14], without
the necessity of range switching, the rate of frequency change per revolution of the knob increasing if the knob is turned faster. This
makes it possible to tune through the whole frequency range very
rapidly.
If 100 Hz resolution is selected, the last two digits of the frequency display are always zero.
4-9
To return to digital frequency tuning (4.4.1}, the required frequency
can be entered directly on the numerical keyboard "12].
4.4.3
INCREMENTAL FREQUENCY TUNING
For measurements at constant frequency intervals (e.g. with channel or
primary group intervals, for measurement of harmonic frequencies, or
for recording of measuring sequences), operation is particularly simple if the frequency of the SPM-16 can be preset with a stored frequency increment. The unit then permits either manual or automatic
frequency stepping.
4.4.3.1
Manual Frequency Stepping
- Depress pushbutton "fsTEP"
Enter the required frequency increment in MHz or kHz
(see section 4.4.1}.
- Depress pushbutton "f" and enter the starting frequency
(see section 4.4.1).
- The frequency can now be stepped upwards or downwards
with the two direction pushbuttons:
Tuning is possible over the whole frequency range.
VISTEP
o_j
The selected frequency increment can be checked by depressing the
pushbutton "fsTEP". The value of the frequency increment is changed
by overwriting \'Jith a new input.
4.4.3.2
Automatic Frequency Stepping
This type of frequency tuning can be used only if the start and stop
frequencies are also entered.
Example: Measuring the residual carrier signals in a primary group of
60 kHz to 108 kHz.
Depress the following pushbuttons:
- "fSTART II
11
-
4-10
f
STEP " 4
64
"kHz" "fSTOP
"kHz"
II
108
"kHz"
-Select the required stepping rate in the windovt "SWEEP OR STEP
TIME/s" vtith rocker Sltlitch [17]. (The rate is stepped automatically
as long as the switch is depressed).
11
- Depress the pushbutton "STEP twice. The LED alongside AUT0 must
light. The frequency is now stepped automatically. After complete
cycle, a ne\·1 cycle starts at fSTART" The elapsed time for one
frequency change results from the total of the STEP" time and the
measuring time; this depends on the measuring conditions.
11
11
11
The frequency sequence can be stopped by depressing the pushbutton
"MHz, kHZ 11 or any other pushbutton in selection panel [7] or [13].
Note:
If the frequency sweep jf = fSTOP - fSTART is not an integral multiple of fSTEP' then measurements will be carried
out only up to an upper frequency f'sTOP = n · fSTEP
~ fSTOP' i.e. the selected limits are never exceeded. The
limits can be exceeded only with the two STEP direction pushbuttons L" • If the pushbutton STEP" is again depressed
(position AUTO), then the SPM-16 again returns to frequencies
within the limits.
11
4.4.4
11
TRANSFERRING THE FREQUENCY SETTING TO THE MEMORIES FOR fSTEP AND THE
SWEEP LIMITS
If pushbutton "f is held down and one of the pushbuttons under ENTRY
AND DISPLAY [7J is depressed, then the currently selected frequency
can be transferred directly to the memories for fSTEP and the sweep
limits.
11
This type of frequency setting is particularly advantageous for measurement of harrronic frequencies or for narrow band sweep frequency
operation (with center frequency setting), if the basic frequency or
the center frequency (after tuning to the maximum level) has a large
number of digits and is an odd number (see section 4.13).
Example:
of harmonic frequencies
(tuning to n ·basic frequency).
- Tune the SPM-16 to the basic frequency.
- Hold down the pushbutton f" and depress pushbutton "fsTEP"
-Tune to the 2nd, 3rd, •.• harmonic frequency by depressing the direction pushbutton {r the appropriate number of times.
~leasurement
11
4-11
The functions search, TRACK, and sweep are described in sections (4.11
to 4.13).
4. 5
AUTOMATIC LEVEL CALIBRATION
"AUTO CAL"
The Level Meter SPM-16 has an automatic level calibration circuit
which makes manual calibration unnecessary. It guarantees a high measuring accuracy over the whole frequency range, a noticeable reduction
in the measuring times, and high long-term stability.
The automatic level calibration circuit is switched on if the red LED
above pushbutton "AUTO CAL" is not lit.
Calibration is carried out after any parameter change which could result in an error in the level display, for example:
- after switching on
- after a frequency change of more than 10 % for frequencies < 10 MHz
or 1 % for frequencies ~ 10 MHz.
- after switching the bandwidth, the operating mode analog/digital,
the meter scale range 1-(20)-80 dB, or the measuring mode absolute/
relative (analog measurement).
If no parameters are changed, for example during continuous monitoring, calibration is carried out every two minutes. In selective mode,
the calibration frequency is always equal to the frequency to which
the meter is tuned (frequency display D), thus the frequency response
of the SPM-16 is virtually eliminated. In the "wide-band" position of
the Level Meter, calibration is always carried out at 10 MHz.
A black bar and the letters CAL are displayed at the upper left corner of the level display during calibration.
For measuring tasks where the automatic calibration cycle would
result in interference, the automatic level calibration circuit can be
switched off by depressing pushbutton "AUTO CAL" ; this applies, for
example, to measurements with the built-in demodulator. No calibration
is carried out during search or sweep frequency operations.
Depression of pushbutton "AUTO CAL" causes the red LED (CAL OFF) to
light. Depressing the pushbutton again immediately initiates a calibration operation and switches off the LED; then the SPM-16 operates
again in the AUTO CAL mode.
4-12
Remarks:
With the internal program configuration of the instrument
the design has already taken into account that unnecessary
switching processes of the HF calibrated attenuator ought to
be avoided in order to prevent premature wear.
The user can likewise take this into account through his
own meaasuring or program runs, and for instance for overview measurements that have frequent changes of frequency,
the calibrator
could be switched off.
0
4.6
SELECTION OF THE OPERATING MODE ANALOG/DIGITAL
11
ANLG/DGTL 11
Analog or digital level display can be selected with the two pushbuttons 11 ANLG", "DGTL 11 • One of the two LED •s above the pushbuttons is
always lit. Analog level display is advisable for S\'Jeep, search, and
TRACK operations or if the demodulator is used.
During analog level measurements, the measuring range can be selected
manually or automatically after depressing a pushbutton; for digital
level measurements, adjustment of the attenuator is always carried out
automatically.
Automatic range setting during selected measurements is always executed with an automatic overload check of the wide-band section. The
principle used here has the advantage that measurements are always
carried out at the optimum settings of the SPM-16, thus achieving the
maxi mum measuring accuracy. The changeover switch 11 low noise/low
distortion 11 , \vhich previously often caused confusion, is no longer
required.
4.6.1
DIGITAL LEVEL MEASUREMENT
Depression of the pushbutton 11 DGTL 11 SHitches off the meter B and the
result of measurement is displayed in the digital level display A as
follows:
4 digits (resolution 0.1 dB)
for wide-band measurments
for selective measurements with fast display (LED beside pushbutton
11
AVRG 11 is off).
5 digits (resolution 0.01 dB)
for selective measurements with slow display (LED beside pushbutton
11
AVRG 11 is on).
4-13
Input levels which cause major deviation of the display, for example
due to superimposed interference signals or insufficient displacement
from the intrinsic noise, are always displayed with a resolution of
0.1 dB, even if display averaging is switched on (see also section
4.6.4). The following parameters can be displayed or stored by depressing the pushbuttons on DISPLAY control panel [3]:
4.6.1.1
Absolute Voltage or Power Level
"ASS"
Depression of the pushbutton "ABS" causes the absolute value of the
signal at the input to be measured and displayed. The required
calibration voltage level (dB) or power level (dBm) must be selected
with the slide switch [46] on the rear of the unit before switching on
the STMS.
, _l~::!~.~=~c~l-~,~~!~i"o~n- can~ also be ~e-~,R~-CctL--~~-~-~~-~-the keyboard
dB ca 1i brat ion:
"MEW
9900
:
[12].
------~Bm_:~~~ i ~$~---~~~M~~-~: -----.,~-=-901
"RCL u
i
the basic setting after the SPM=To'hcrs·~been~swi'tched on, however, is
always according to the position of the slide switch [46].
4.6.1.2
Level Difference
For measurement of the frequency response or of harmonic frequencies,
the level referred to a reference value is more interesting to the
user than the absolute level. For these measurements, the absolute
value is first determined as described in section 4.6.1.1 and then
stored as the reference value. This is done by depressing pushbuttons
"ABS" and "REF" simultaneously.
Note:
The function AFC [5] should be switched off.
The new, stored reference level is now displayed in display A with a
resolution of 0.01 dB. To display the reference level, simply depress
the pushbutton "REF".
Up to 11 different reference levels (e.g. intrinsic·frequency response
of a comparison device) can be stored with the MEM function (see section 4. 22).
Any required reference levels can be programmed if the SPM-16 is used
together with a computer.
4-14
Depression of the pushbutton "ABS-REF" causes the difference between
the measured level (absolute value) and the reference level stored as
described in section 4.6.1.2 to be displayed in dB. The resolution of
the display depends on the conditions mentioned in section 4.6.1.
4.6.1.3
Reduced Level
In telecommunications technology, levels are often not specified as
absolute values, but as values referred to the relative level of a
test point. To simplify evaluation of such levels, the relative can be
set between the limits
-99.9 and +20.0 dBr
The measured result is then displayed directly as a ''reduced level"
in dBmO (dBO) if the pushbutton "dBmO" is depressed Any reference
level can be entered instead of the relative level (dBr).
a)
Display of the relative level
The last relative level which was stored can be displayed by depressing pushbutton "dBr" once (left LED lights).
b)
Input of the relative level (dBr)
- Depress pushbutton "dBr" once or twice unt i 1 both LED's above
the pushbutton are lit.
- Enter the required dBr level on the keyboard [12].
(Numerical value and units with sign)
Positive values (+dBr) with pushbutton "MHz"
Negative values (-dBr) with pushbutton "kHz"
Depression of the unit pushbutton transfers the new value to the memory (and the frequency display again appears).
Actuation of the pushbutton "dBmO" causes the level to be displayed,
not as an absolute value, but referred to the stored (relative level)
(dBr) as a reduced level in dBmO or dBO.
The following relationship applies: a dBmO + b (dBr)
= (a+ b) dBm
4-15
4.6.2
ANALOG LEVEL MEASUREMENT
Depression of the pushbutton "ANLG" switches off the digital level
display and switches on the analog meter. The digital display A now
shows the measuring range, i.e. the level value for the 0 dB mark of
the meter which can be switched, according to the selected scale (10],
in
1 dB steps for the 1 dB scale or
5 dB steps for the 20 dB and 80 dB scales.
Result of measurement = digital display (measuring range) + meter
reading (scale value).
4.6.2.1
Measuring Range Selection
The measuring range is selected
a) manually via the measuring range switch [9] or
b) automatically through the depr·ess i ng of pushbutton 11 AUTO SET 11
In the case of manual selection (input of the measuring range for
sweep operations or the level threshold for search operations), select
a measuring range so that measurements are carried out at the upper
end of the 20 dB scale (for accuracy reasons).
If automatic range selection is activated by depressing pushbutton
"AUTO SET" once, the measuring range is always set so that the meter
indication is to the left of the 0 dB mark.
The advantage of this lies in the simple addition of two negative
values (measuring range and analog value) in most applications.
Maximum extent of the measuring range:
for the 1 dB scale : +10 dB (+20 dBm)
for the 20 dB scale: +10 dB (+20 dBm)
for the 80 dB scale: +10 dB (+20 dBm)
-120 dB (-110 dBm)
-120 dB (-110 dBm)
-40 dB (-30 dBm)
Note: If, when the 80 dB scale is selected or when the unit is
switched from the coaxial to the balanced input, a direction arrow
appears"lrin the measuring range display for the most sensitive measuring range (see section 4.6.3), turn rotary switch [9] anticlockwise
(against the direction of the arrow) or depress the pushbutton
"AUTO SET". If the arrow appears in the 1 dB range, turn the rotary
switch anticlockwise and then clockwise again or depress a function
4-16
key·
4.6.2.2
Scale range
Three scale ranges are available for level display. The desired range
is selected by one of the three pushbuttons "1 dB" "20 dB" "80 dB"; at
the same time, the LED for the appropriate scale in the meter is lit
(see Figure 4-3).
The scales span the following values:
1 dB scale:
+0.3 dB
Used for measurement of single, discrete signals with
maximum accuracy or for measurement of small level differences.
20 dB scale:
-20 ••• +2 dB
Used for general measurements, for noise measurements,
during search, or TRACK operations, or for distortion
measurements.
80 dB scale:
-80 ••• +0 dB
Used for overview and sweep frequency measurements with
large level differences.
-1.5
The bottom scale on the meter is used for measurement of phase jitter
(see section 4.9) in analog mode. The range extends from 0.3 to 30"
and is logarithmically divided to provide maximum resolution for small
jitter value readings.
LEo•s for
level reading:
-~
expanded (20 Gl 84) ---+t-~
norma 1 20 dB (20 Gl 85 )---.-.::-J
~
~u\ \
normal 80 dB (20 Gl 86)-~
,a>~,"~
"'
~. <0<-?
Phase jitter reading --~:-J
~":l
<:!
'---------~--------------------------~~
(20 Gl 87)
I
"- '
Figure 4-3 Meter scale of the SPM-16
4-17
4.6.2.3
Fast Signal Detector
The LED alongside the meter is used as a tuning aid for rapid location of unknown signals when tuning manually in 1 dB or 20 dB scale
range.
If the frequency of the Level Meter is changed rapidly with knob [14],
see section 4.4.2, the signal detector with the LED reacts more rapidly than the relatively slow analog meter. The LED lights as soon as a
signal whose level would result in a deflection outside the scales
marked -15 dB or -1.2 dB is present at the receiver input.
In search mode (see section 4.12), illumination of the LED is also
used as a criterion for automatic stopping of automatic frequency
tuning.
Note: 1) In the more sensitive measuring ranges, the LED may also
light at a scale indication < -15 dB, according to theselected bandwidth, because the peak evaluation of the signal
detector can permit single noise spikes in the receiver noise
to illuminate the LED. This can be prevented by selecting a
narrower bandwidth.
2) If the 80 dB scale is selected, the LED lights continuously.
4.6.3
DIRECTION ARROWS IN THE LEVEL DISPLAY
Direction arrows in the level display (Figure 4-4) signal an intolerable measuring range in analog mode and an intolerable result in the
digital mode; in digital mode, they also indicate that the level at
the meter input is higher -t-or lower "'than the currently displayed
level, as the result of a level hit during measurement.
CAL
..
REF LIN"'
Ill-
_/
~/_/_
I
dB
"'
..J
"'
~----------------------------~~
Figure 4-4
Direction arrows in the level display
The direction arrows disappear
In analog mode: in the 20 or 80 dB scale by depressing the pushbutton "AUTO SET" or turning the measuring range switch
4-18
[9] one position anticlockwise (against the direction
Digital mode:
4.6.4
NOISE AVERAGING
of the arrow).
In the 1 dB scale, by turning the range switch [9] one
position anticlockwise and then clockwise again or by
depressing a function key in display panel [3] (the
direction arrow indicates that the display expander is
not measuring a signal).
after one further measurement.
11
AVRG"
Level measurements are normally carried out with noise averaging
switched off (LED off). When signals with overlaid noise or the basic
noise of a system is measured, the display would be unstable. Thereupon, noise averaging is switched on by the depressing of the pushbutton 11 AVRG" (LED lights). So the measured value is averaged over a
longer period, wherein the digital mode implements formation of the
average value from a number of single measurements.
In digital mode, with selected measurements, and with noise averaging
on, the resolution is 0.01 dB. If the signal-to-noise ratio is too low
or if the signal fluctuates, the display automatically switches to a
resolution of 0.1 dB. Wide-band measurements are always carried out
with a resolution of 0.1 dB.
4.7
BANDWIDTH
4.7.1
WIDE-BAND SECTION
The Level Meter SPM-16 operates in the frequency range 10 kHz to
160 MHz as a wide-band receiver if the bandwidth switch, [16], is set
to the position 11 WIDE 11 • This mode makes it possible, for example, to
measure the wide- band loading level, i.e. the baseband load, in all
CF systems with 12 to 10800 channels. Due to the rectifier characteristic, a noise signal like the loading level of CF systems actually
carrying traffic, like thermal noise, or like intermodulation noise
results in a meter reading of practically the same effective value as
for a sinusoidal signal.
4-19
The measured level can be displayed in either analog or digital form.
In the case of digital display, the resolution is 0.1 dB.
4.7.2
SELECTIVE SECTION
The SPM-16 can be set to five different bandwidths. Typical selectivity curves of the Selective Level Meter are shown in section 5.1. Depending on the application, one of the following bandwidths is selected with the bandwidth switch, [16]:
Bandwidth 25 Hz
The narrowband filter is used mainly for analysis of signal components
which are closely spaced, for example for measurement of group or super-group pilot frequencies, or to discriminate against excessive
noise at the input.
Bandwidth 400 Hz
This bandwidth is used for sensitive measurements, for analysis of adjacent signals, and to block noise.
Bandwidth 1.74 kHz
This bandwidth permits weighted noise measurements in accordance with
CCITT in the voice-grade channels of the CF transmission band.
Bandwidth 3.1 kHz
The bandwidth of this filter corresponds to the width of a telephone
channel. It has a very low ripple in the pass-band and has steep
skirts at the limits of the band. It is used for measurement of the
unweighted noise and of the power in single voice channels and is automatically selected if demodulation of single sidebaAd signals is activated (see section 4.8). It is also possible to measure impulsive
noise in carrier frequency speech channels if an external unit (e.g.
DLM-3) is connected to the demodulator output [21] (see section 4.8).
Bandwidth 48 kHz
This permits measuring the power in a 48 kHz bandwidth.
As the final intermediate frequency of the Level Meter is 10 kHz, this
bandwidth is realized by rapidly sweeping the SPM-16, with the bandwidth set to 3.1 kHz, around the selected frequency, within a bandwidth of 48 kHz, and with integration of the measured values. The
function 11 SWEEP 11 is thus automatically switched on when the 48 kHz
bandwidth is selected. Sweep measurements are therefore not possible
4-20
1-1ith this bandwidth; however, the two directional "STEP" pushbuttons
"L" for measurements with constant frequency increments can still be
used (the function "AUTO STEP" cannot be switched in).
4.8
DEMODULATOR
The built-in measuring demodulator of the Level Meter SPM-16 permits
demodulation of received signals which have been modulated with a
single sideband. An important characteristic of the demodulator is its
wide dynamic range of approx. 65 dB.
The demodulator is activated with the switch [16], in the two positions~~.The 3.1 kHz bandwidth is always active for these measurements. In addition, the analog mode must be selected. The demodulated
received signal is available at output socket [21] with an output impedance of 600 Q. The output level is approximately 0 dBm if the meter
indicates 0 dB on the 20 dB scale and if the load impedance is 600 Q.
The intrinsic noise at the demodulator output is around -65 dBm, and
the overload limit is approximately +10 dGm.
+10
1
....,
0
:::l
!} dBm
:::l
0
....,~
-20
IU
:::l
"0
0
E
QJ
-o
....,
-L.O
IU
.-QJ
>
QJ
_J
-60
I
-BO
-60
-40
-20
0
Channel noise or level
Figure 4-5
+10 dBm
-
Dynamic range of the measuring demodulator
Relative Level -50 to +10 dBr.
If CF systems with up to 10800 channels are used, the best load is
achieved if the relative level (dBr) is set to match the system access
point and a measuring range of 0 dBmO is selected. The dynamic range
which can be handled by the SPM-16 is shown in Figure 4-5.
4-21
Switch [16] permits selection of
~~ demodulation of the lower sideband (inverted position) and
~= demodulation of the upper sideband (upright position).
The center frequency of the band is converted to 2 kHz when tuning is
to the midchannel. If the level meter was previously tuned to the suppressed carrier, it must be detuned for correct demodulation, namely
by -2kHz for!l!liilllband by +2 kHz fordl1llllill. With a bandwidth of 3.1 kHz,
this results in a demodulated audio frequency band of 450 Hz to
3.55 kHz.
The demodulated input signal can also be monitored with the built-in
loudspeaker. The volume of the loudspeaker can be adjusted with potent i omet e r [20 ]•
The automatic level calibration circuit can be switched off with
pushbutton "AUTO CAL" if the short interruptions of the signal cause
interference during the measurements (e.g. interruption measurements).
Additional instruments such as interruption meters and impulsive
noise counters can be connected to the demodulator output [21] for
further processing of the converted signal. The Data Line Test Set
DLM-3 from Wandel & Goltermann is suitable for both of the above
tasks.
For interruption measurements in accordance with CCITT 0.61, the
Selective Level Meter is tuned to the frequency of the carrier frequency test signal and the resulting 2 kHz signal from the demodulator
is extracted at output [21]. The automatic level calibration circuit
must be switched off.
Owing to the wide dynamic range of the measuring demodulator and to
the flat 3.1 kHz filter, the Level Meter is particularly suitable for
translating carrier frequency telephone channels into the AF range. In
order to avoid measurement errors, particular efforts were made to ensure that all modules which participate in translation reproduce the
characteristics of CF channel translators as closely as possible. For
this reason, the SPM-16 can be used with an external counter in accordance with CCITT 0.71 for impulsive noise measurements over the
whole frequency range of the Level Meter.
4-22
The crystal controlled frequency tuning permits precise counting of
events over long periods.
4.9
PHASE JITTER MEASUREMENTS
Phase jitter measurements with digital or analo0 display can be carried out in order to assess the transmission qualities of telephone
circuits used for data communications.
L9.1
1
CAUSES AND EFFECTS OF PHASE JITTER
Phase jitter on data circuits routed over carrier frequency channels
results mainly from unwanted phase modulation of the carrier signals
participating in the frequency conversion on the transmit and receive
sides. Interference components such as the audio frequency ringing
signal or harmonics of the mains frequency are the sources of the
phase modulating signals. The intrinsic channel noise also has a certain effect in creating phase jitter. Phase jitter changes the zero
crossings of the data signal and can result in erroneous bits on the
receive side after regeneration of the signal.
This makes it necessary to check data circuits to ensure that their
phase jitter values lie within specific maximum limits. In addition to
national PTT Administrations, which have issued regulations governing
this impairment, the CCITT also specifies maximum values.
4.9.2
SETTINGS ON THE LEVEL METER
For measurement of phase jitter in the frequency range 10 kHz to
160 MHz, switch [16] is used to select the position ~pp' and the
appropriate operating mode [4] analog "ANLG" or "DGTL" is selected.
The bandwidth of 3.1 kHz is automatically selected. The weighting filter and the rectifier characteristics for measurement of the peak-topeak value comply with CCITT recommendation 0.91.
For measurement, the signal level should be ~-50 dBm (-60 dB). If the
signal is too low or is not present, the SPM-16 produces an
Error Annunciation
for analog display:
by full-scale deflection of the meter and by
switching off the signal detector C.
4-23
for digital display:
by a warning arrow ~in the level display and
a jitter indication of 3o.o·.
Tuning
of the receiver depends on the measuring task assigned to it, the following applications being possible:
a)
Measurements of a single tone or in a carrier frequency voice
channel in a system, in the vicinity of which no signals (adjacent
channels, pilot frequencies, dialling tones) exist except for the
test tones. In this case, the meter is tuned to the tone to be
measured.
b)
Measurements in an unoccupied CF channel.
In this case, the SPM-16 should be tuned precisely to the center
of the channel. The frequency position of the measured signal
within the 3.1 kHz bandwidth has no effect on the measurements.
Display
of the result is either on the logarithmically divided lower scale of
the meter or on the digital display, with an indication range of 0.3
to 30".
The resolution of the digital display is
for phase jitter values <!>PP ~ 4"
for phase jitter values 4" < <!>
PP
for phase jitter values 10" < <I>
PP
..
0.1.
. 0.2"
;i 10" .
. o. 5 ••
;i 30" .
The minimum indicated digital value is 0.3·. The intrinsic jitter of
the level meter is typically 0.3".
For external processing of the phase jitter result, the Y-voltage output [22], see section 4.14, can be used for driving a strip recorder.
4.10
AUTOMATIC FREQUENCY CONTROL
11
AFCU
The AFC serves for automatically tuning the synthesizer to input signals whose frequencies are unstable. It can also be used as a tuning
aid for input signals whose frequency is not precisely known. In order
to permit AFC to function correctly in the case of selective measurement with bandwidths of 25 Hz to 3.1 kHz, the SPM-16 should first be
tuned in analog mode until there is a meter indication on the 1 dB or
4-24
20 dB scale. After this, the AFC is switched on by depressing the
pushbutton "AFC", causing the synthesizer to tune itself precisely to
the signal frequency and the level indication to reach the maximum
value.
In the operating mode SEARCH - see section 4.12 - the AFC is switched
on automatically when an input signal (single signal or single spectral line) appears within the pass-band of the the IF filter (capture
range).
The AFC is also active in the digital roode.
If the signal is missing or noisy, the AFC switches itself off, and
the LED above pushbutton [5] starts to flash.
Although the capture range of the AFC is restricted to the nominal
bandwidth of the selected filter, the lock range extends over the
whole frequency range of the Level Meter. If the signal frequency
changes slowly, then the frequency display will change accordingly. In
this case, the Level Meter acts as a F R E Q U E N C Y C 0 U N T E R.
4.11
TRACK MODE
4.11.1
APPLICATIONS
In this ~~de, the SPM-16 can be used as a tracking receiver for
selective, automatic end-to-end measurement without any additional
connection for frequency synchronization. Measurement is carried out
in CF systems in the gaps between the contiguous groups, which means
that the system can remain carrying traffic, in contrast to end-toend sweep frequency measurements with a wide-band receiver (see Figure
4-6). A prerequisite for execution of this measurement is that a level
generator with a similar frequency generation system and facilities
for storage of a specific number of fixed frequencies is available
(e.g. PS-19, PS-6/60 with OD-600/00F-601 or PS-8/PS-12 with OD-4/0D-12
and ODF-601). The fixed frequencies correspond to the CCITT recommendation for gap frequencies (additional measuring frequencies).
If the generator and receiver are programmed with identical frequencies (see section 4.22.3), measurement is started by initiating sequential, cycling transmission of the various frequencies from the
level generator (with soft level blanking), while the SPM-16 in the
4-25
(Location A)
(Location B)
G ~ l<Generator
Figure 4-6
-""' X
<-
-)
SPM-16
Printer
or plotter
Transmission system
Selective
or
receiver
translator with frequency offset
(upright or inverted position)
Receiver tracking
position TRACK waits at one of the fixed frequencies, f n • When the
generator frequency f = f , the SPM-16 indicates a level on the
s
n
analog meter during the dwell time at this frequency. When the generator switches to the next frequency, the level indication disappears
and the LED of the signal detector C is switched off. The extinguishment of the LED causes the SPM-16 to switch to the next higher or
lower fixed frequency, according to the program. The generator and the
receiver are now synchronized. A plotter with pen lift function
(SPM-16, series 8 or later) can be connected to the X-Y output [22]
[23] or a printer with V.24/V.28 interface can be connected to the
printer interface (Auxiliary de!vice for SPM-16, series B or later) for
recording the measured values.
For measurements on translators (channel, group translators, etc.),
the generator and receiver frequencies can be programmed with any required fixed offset frequency in the upright or inverted position.
4.11.2
SETTINGS ON THE LEVEL METER
- Enter the fixed frequencies with
a) Push button 11 MEM" (see section 4.22.3) or
b) Pushbuttons 11 fSTARTu' "fsToP", "fsTEPu (see section 4.4.3)
(frequency stepping with equal increments).
- Tune the Level Meter to the starting frequency, which can also be
fSTOP for measurements in the inverted position.
- Select analog mode and the 20 dB scale.
- Set the measuring range switch [9] to the expected level
(~approximately full-scale deflection).
4-26
- Further settings:
STEP TIME/s
Generator Receiver
0.3
0.1
1
0.3
3
1
CAL
[1]
OFF
ON/OFF
ON/OFF
AVRG [11 J
OFF
OFF
ON/OFF
The switching rate of the generator must be matched to the settling
time of the generated level and of the unit being tested, to the settling time of the receiver, and perhaps to the time required for a
connected printer to print the results.
-Activate the function "TRACK" by depressing the pushbutton "STEP"
once. The Level Meter now waits for the first frequency.
The DC voltage present at the X-output [23] is proportionar-to the
frequency within the start and stop frequency limits.
Open circuit voltage at fSTART ••••••••••••••••••••••••••••• -2.5 V
fSTOP
····i·························
+2.5 V
f STEP
_f
STOP
START
The DC voltage present at the Y-output [22] is proportional to the meter reading. The open circuit voltage for full-scale deflection is
+5 v.
Open circuit voltage per frequency step fSTEP -_
4.12
r:
~
•
V f
SEARCH
The function "SEARCH" permits automatic searching for signals of unknown frequencies which lie above a preset level threshold, such as
single interference lines or excessively high levels (hot tones) in
communications systems.
The leve1 threshold is set in the analog mode with the measuring range
switch [9], normally in the 20 dB scale range. As the search stops
when the signal detector (LED C) lights, the lower reaction threshold
of the signal detector must be taken into account for correct selection of the measuring range. The reaction threshold is as follows for
the various scales:
4-27
1 dB scale: approximately -1.2 dB
20 dB scale: approximately -15 dB
80 dB scale: at approximately -40 dB (LED lights continuously)
Setting example for the level threshold:
Level values > -80 dB should be searched for in the 20 dB scale
range. Set the measuring range to (-80 +15) dB = -65 dB.
In the case of low input levels in the vicinity of the intrinsic
noise of the Level Meter, it is recommended to select a narrow bandwidth. Otherwise single noise spikes could cause the signal detector
to react and block the search operation (see section 4.6.2.3).
Search operation is possible with the bandwidths 25 Hz to 3.1 kHz.
The search speed is matched optimally to the selected bandwidth, as
shown in the following table. When the 80 dB scale is switched in, the
search speed is lower.
Bandwidth
3.1 kHz
1. 74 kHz
Search speed
1 MHz/s
250 kHz/s
ii 400
l
Hz
20 kHz/s
25 Hz
200 Hz/s
Calibration is carried out in accordance with the criteria specified
in section 4. 5.
T'tiO different operating modes can be selected, these are described in
more detail in sections 4.12.1 and 4.12.2.
4.12.1
SINGLE SEARCH (FULL RANGE) "SEARCH"
In this mode, the search function is executed over the whole frequency
range, independent from the stored frequency limits fSTART and
fSTOP" It is recommended. particularly for slow search speeds (narrow bandwidths), that a starting frequency be set up by depressing
pushbutton "f" or "fsD\RT 11 and entering the frequency vi a the keyboard [12]. After the level threshold has been set (see section 4.12),
the search is started by depressing one of the SEARCH directional
pushbuttons "F" • As soon as the signal detector (LED C) lights, the
search function stops. At the same time, the AFC [5] is switched on
(section 4.10) and tunes the Level Meter precisely to the single tone
or to a discrete spectral line at the meter input.
4-28
The search can be restarted at any tirne
SEARCH direct i ona 1 pushbuttons "F".
by
depressing one of
th~:~
h1o
If the input signal is not present or if the measuring range is not
sensitive enough, the search function stops at the frequency band limits. The search can be halted at any time by depressing one of the
pushbuttons "MHZ 11 , 11 kHZ 11 , "MAN 11 •
4.12.2
CONTINUOUS SEARCH OPTIMUM
In position OPTimum of the SWEEPTIME changeover switch [17], the
search is carried out within the frequency limits specified with
fSTART and fSTOP" It is also possible to have the STMS periodically search for excessively high signal levels, with simultaneous evaluation (printout of level and frequency with SPM-16, series B or later). This permits automatic system monitoring.
Settings on the SPM-16:
-Enter the start and stop frequencies (fSTART' fSTOP) as
described in section 4.4.3.2.
- Select analog mode
Select the bandwidth and level threshold as described in section
4.12.
-Select the position 11 0PT" with changeover switch [17].
- Depress one of the pushbuttons SWEEP
SI..JEEP
for periodic search
"SWEEP" _ / for single search
11
11
11
11
N
Select the starting frequency fSTART or fSTOP"
The search can be halted at any time by one of the pushbuttons
11
kHz", "MAN".
11
MHZ
11
,
A plotter can be connected to the X-Y outputs [22], (23] for recording
the interference lines.
In the Level Meter SPM-16, series B or later, an Auxiliary Device, a
printer interface, can be fitted, and which permits the connection of
printers with V.24/V.28 interfaces. Thereupon, the level and frequency
values can be printed, followed by an automatic restart of the search
operation.
4-29
4.13
SWEEP MODE
Sweep frequency measurements in the analog mode are permitted on test
objects having characteristics with extremely steep flanks. The excellent synthesizer properties, like high spectral purity and phase continuity when the frequency changes, allow use of the sweep mode.
Figure 4-7 shows the configuration and interconnections of a sweep
frequency test set-up with the Generator Section PSS-16 and Display
Unit SG-2/SG-3. Operation and calibration of the Display Unit are described in the description and operating manual for the SG-2/SG-3.
The frequency is set digitally with an increment which depends on the
sweep range and the deflection time. The microprocessor calculates the
increment, taking into account that the frequency is stepped every
60 !..IS.
Graticule SGS-209 (309)
\
Ol
\
SG-2/SG-3
y
~
/
-
K 145
SPM-16
n
I
c::J c::J
PSS-16
Figure 4-7
4.13.1
n1
'I
c:::J
Inserts:
SGV-21 Vertical amplifier
SGH-21 Horizontal amplifier
SGR-21 Horizontal reference lines
SGR-22 Vertical reference lines
*
I
c:::::J
00~
00~
)
* BNC cables K 197
Configuration and interconnections of the sweep
frequency measuring set-up (rear view)
SETTING UP THE SWEEP LIMITS
This depends on the application.
For wideband test objects, it is advantageous to enter
fSTART = lower (upper) sweep limit and
fSTOP =upper (lower) sweep limit
via the keyboard [12] (see section 4.4.1).
4-30
For narrow band test objects,
fCENT
center frequency and
~f
= sweep width (fSTOP - fSTART)
are entered (see section 4.4.1).
=
Example: fCENT
=
10 MHz, Llf
Input·. "f CENT " 10
"MHz"
=
"~f"
10kHz
10
"kHz"
11
11
After depression of the push buttons "fSTART and 11 f STOP , the
sweep limits (in this example 9.995 and 10.005 MHz) are displayed in
the frequency display D.
Note:
4.13.2
A frequency appearing in the frequency display D and assigned
to the pushbutton "f 11 can be transferred to the memories for
the parameters in the input panel [7] if pushbutton "f 11 is held
down and one of the pushbuttons in panel [7] is depressed. A
typical application of this is measurement of the test objects
with extremely noticeable resonance points, as with with
crystal filters. (See also section 4.4.4). In this case the
SPM-16 is tuned continuously with pushbutton 11 MAN 11 to a maximum
level indication, and sweep frequency operation is then carried
out with center frequency and sweep width settings.
SWEEP SEQUENCE AND SWEEP TIME
The
t~'/o
pushbuttons "SWEEP" permit selection of
"SWEEP"
y\f
periodic, trianguiar sweep
"SWEEP"
J
single sweep
If the pushbutton whose function is currently active is depressed momentarily during sweep frequency operation, the direction of sweep is
reversed.
Sweep Time
is the elapsed time for one sweep. It can be set in the range between
0.1 and 300 s with the SWEEP TIME switch [17].
In the case of single sweep operation, the starting frequency is se1ected by depressing one of the push buttons "f START" or "fSTOP",
and the sweep is then started by depressing the pushbutton "SWEEP"~
4-31
Checking the settling time of the test object can be carried out
either visually (the sweep-out and return traces of the swept curve
must coincide) or by depressing the pushbutton "SWEEP"J\/\In the
latter case, the deflection is stopped momentarily at regular intervals. If the test object has not settled correctly, this results in a
staircase waveform of the sweep curve and the sweep time should be increased. Depression of the sweep pushbutton is particularly advantageous for slow sweep frequency measurements where the display unit
screen persistence is not sufficient.
4.13.3
MANUAL SWEEP
In the position "MAN" of the S\~EEP TIME switch [17], with one of the
two ''SWEEP" pushbuttons depressed, the frequency can be swept manually
within the limits set as specified in section 4.13.1, using the knob
[14]. The X-deflection voltage at output [23] is proportional to the
sweep-width and its maximum values are .:!:_2.5 V.
If the manual tuning knob is turned slowly, the frequency changes proportionally; if the knob is turned rapidly, the frequency change is
accelerated non-proportionally. But the sweep limits are exactly
kept.
4.13.4
DISPLAY UNIT CONNECTION [42]
The Display Units SG-2 (screen size 120 mm x 85 mm) and SG-3 (screen
size 210 mm x 150 mm) from Wandel & Goltermann are suitable for display of a sweep frequency curve.
The Display Unit should be connected via a suitable cable (e.g. K 145,
see also Figure 4-7) to socket [42] on the rear side of the SPM-16. No
further cable connections are necessary.
The X- and the Y-signals for horizontal and vertical deflection of the
sweep curve are available at the Display Unit connector (see Figure
4-8 for pin assignments). The signals are equal to the DC voltages at
the Y-output [22] (see section 4.14) and X-output [23] (see section
4.15).
The level values of the horizontal reference trace generated within
the Display Unit can be displayed on the SPM-16 with series B, via
connector [42]. Three horizontal reference lines (traces) can be set
4-32
Pin
4
J
J
r
L
5
[
[
[
6
_j
C
9
J
[
J
J
Figure 4-8
10
12
13
14
Signal designation
tch to reference trace voltage
Pen lift function H - pen up
H - pen dovm
S~·ii
X-deflection voltage
Y-deflection voltage
Measuring trace blanking
Y-reference trace voltage
Ground
Pin assignments of the Display Unit connector [42]
up in the Reference Trace Plug-in SGR-21 for measuring the sweep
curve. The intensity of one trdce can be increased with respect to
that of the other two traces by depressing a pushbutton. At the same
time, the meter reading of the Level Meter is switched from the received level to the reference trace level. A black bar and the test
"REF.LIN." appear in the bottom left corner of the level display A.
The display mode should be taken into account as described in section
4.6.2, when reading the level value.
The pen lift control (SPM-16, series B or later) simplifies operation
of plotters connected to socket [42]. With suitably equipped plotters
with TTL-control (e.g. HP 7015 B), this function ensures that the pen
is lifted during setting up of the sweep conditions and is lowered
onto the paper only when a single sweep is initiated.
The pin assignments of connector [42] are shown in Figure 4-8.
4.14
DC (Y-) OUTPUT [22]
A Y-deflection voltage which is proportional to the meter indication B
is available at output [22], for example for driving a plotter. The.
open circuit voltage is +5 V for full scale deflection of the analog
meter, with an internal resistance of 5 kQ. This DC voltage is also
available at the 14-pin socket [42] on the rear of the SPM-16 (see
section 4.13.4).
4-33
4.15
DC (X-) OUTPUT [23]
The DC (X-) output [23] supplies a deflection voltage which is proportional to the frequency within the frequency limits fSTART and
fSTOP' for example for driving a plotter or a display unit.
Regardless of the selected range, the open circuit voltage is
at fSTART: -2.5 V
at fSTOP : +2.5 V
with an output impedance of 5 kQ.
This DC voltage is also available at the 14-pin socket [42] on the
rear of the SPM-16 (see section 4.13.4).
4.16
10 kHz IF OUTPUT [43]
The last intermediate frequency (IF) of 10 kHz can be extracted at
the output socket [43] on the rear of the unit. This output is suitable, amongst other things, for connection of plotters with AC inputs
and of very selective analyzers.
The output frequency is always 10 kHz, even in wide-band mode.
At meter indication of 0 dB and with an output impedance of 600 Q,
the output level is -10 dB when terminated with a 600 Q load.
4.17
REMOTE CONTROL OF THE LEVEL GENERATORS PS-16 AND PSS-16 (TRACKING
GENERATOR OUTPUT)
The Level Meter SPM-16 can be combined with the above mentioned level
generators to form a complete level measuring set.
If the Generator and Receiver are used at the same location, their
frequencies can be tuned synchronously from the SPM-16. This operating
mode, in which the Level Meter controls the Level Generator, provides
considerable simplification of operations. For remote control of the
Generator from the SPM-16, the control output [44] of the SPM-16 is
connected by a coaxial cable to the control input of the Generator
Section PSS-16. (See Figure 4-7). When this connection is established, '
the two units operate synchronously.
Output [44] can also be used as a constant level output for frequency
response measurements in frequency range 10 kHz to 160 MHz. The output
level is -15 dBm, and the output impedance is 75 Q.
4-34
4.18
STANDARD FREQUENCY INPUT [51]
If the specified frequency accuracy of the SPM-16 is not sufficient
for specific measuring tasks, an external standard frequency of 1, 2,
5, or 10 MHz can be connected to socket [51] on the rear of the unit
to achieve a smaller error in the tuned frequency.
The necessary level with a sinusoidal input signal may lie between
-10 and +10 dBm; for square-wave signals, the voltage V may lie
PP
between 200 mV and 2 V (75 Q input impedance).
4.19
DIGITAL INTERFACE [40] [41]
The Level Meter SPM-16 includes a
which is available externally via
sockets [40] and [41] on the rear
devices can be connected to these
for connection. Address (2), data
transmitted across the interface.
4.20
digital, device-specific interface
the two 24 pin parallel connection
of the unit. Additional external
sockets. The cable K 366 is suitable
(8), and control (3) signals are
COMPUTER CONTROL
All functions of the Level Meter SPM-16 can be controlled by an external controller. This makes it possible to include the Level Meter
in automatic measuring systems where it can handle comprehensive measuring tasks not only accurately and reliably, but also rapidly and at
low costs. Figure 4-9 shows the configuration of a simple automatic
level measuring system, which is capable of further extension.
Periphery
I EC 625
.---,
I
I
I
I
L _ _ _J
.___PSS_____.-16
fs=f~,IX ~~
Level Meter
Test object
Level
Generator
Figure 4-9 Block diagram of a simple automatic level
measuring system.
0
Controller
The computer control is connected via the optional Interface Bus
(IEC 625) Card, BN 853/02) ~r1hich is inserted into the rear of the
4-35
level meter. Connection to systems with IEEE 488 interfaces requires
an additional adapter plug S 834. Subsequent installation of the interface board is described in chapter 6. The external control of the
SPM-16 is signalled by indication of the red LED above pushbutton
11
LOCAL 11 • As long as this LED is on, manual operation via keyboard input is blocked.
It is possible to switch to manual control with the computer connected by depressing the pushbutton 11 LOCAL 11 ; this is done in accordance
with conditions specified in the IEC bus standard (remote/local function RL1). Details of programming of the Level Meter can be found in
the separate manual 11 Remote control and programming of the SPM-16".
_!~---,
v
~---------------------------------------,
~-----------------l
~
]
Ooto
bu5
Figure 4-10 Block diagram of the interface Bus (IEC 625)
4.20.1
INTERFACE BUS (IEC 525)
Figure 4-10 shows the simplified block diagram of the Interface Bus
(IEC 625). For better understanding of the following description of
the Interface concept reference to the "Interface Bus (IEC 625)" Brochure is recommended.
For the microprocessor. the Interface Bus (IEC 525) is nothing more
than a group of input and output ports. Data are exchanged between the
IEC bus and the Level Meter via these ports, and the exchange is controlled by the IEC bus program. The PROM's which contain this program
are not located on the interface board but are within the Level Meter.
4-36
The actual interface logic is located in a single integrated circuit:
On the one side the interface is connected to the IEC Bus via the required driver and receiver circuits, and on the other side the comb
connector is connected for the I/0 Bus of the microprocessor within
the SPM-16. This interface logic handles a major part of the interface
tasks independently, i.e. without using the microprocessor of the Level Meter. It automatically handles for example the IEC bus handshake
cycle and decodes all messages \'lhi ch are transferred across the IEC
Bus.
The interface statuses resulting from these messages are written into
the appropriate input ports.
A further input port is used as a transfer register for listener da-
ta, representing data transferred from the IEC Bus to the Level Meter
as long as the Level Meter is addressed as a listener, for example,
when parameters for setting the SPM-16 are being transferred.
The output ports are used for:
reception of control commands with which the microprocessor can affect the behavior of the interface logic (for example, in addition
to a wide range of other possibilities, it can stop the handshake
cycle or transmit a service request signal (SRQ) via the IEC Bus).
- transferring data which are to be transmitted from the Level Meter
to the IEC bus, e.g. talker data and status information.
Talker data are transmitted from the Level Meter to the IEC Bus as
long as the Level Meter is operating as a talker, for example when
the result of measurement is being transferred.
The status information is the Level Meter's response to a serial
poll and includes the current status.
The Level Meter address can be set up on an address switch (see
Fig. 6-2).
The "PP" sv1itch (see Fig. 6-2) permits selection of the data circuit
to the IEC Bus on which the Level Meter is to transmit its Request
Service Signal (RQS) if the controller carries out a status request by
a parallel poll operation.
4-37
4.20.1.1
INTERACTION BETWEEN THE LEVEL METER AND THE INTERFACE BUS (IEC 620
When the IEC Bus has reached a status in which operation by the internal microprocessor is necessary, the IEC Bus interface transmits an
interrupt signal to the Level Meter. As a result of this interrupt,
the microprocessor then executes the IEC Bus program. This is always
the case:
- if the Level Meter is to be switched from manual control (LOCAL) to
reroote contra l or from reroot.e contra 1 to manual centro l.
- if listener data was transmitted across the IEC Bus. The interface
logic has then written this data into the transfer register for listener data and stopped the handshake procedure. The handshake procedure remains interrupted until the microprocessor reads this byte
(then NDAC transits to false i.e. data accepted). After processing
and storage of the listener data, NRFD is false i.e. device ready
for data can then be transmitted.
if the Level Meter must provide a new talker byte. During writing of
the new talker byte into the appropriate output port, the handshake
procedure is started (DAVis true i.e. data are valid).
- if a measurement is to be initiated in the Level Meter by the IEC
Bus comnand "device trigger (GET = Group Execute Trigger)". The interface logic has interrupted the handshake procedure and this procedure remains interrupted until the microprocessor has started the
measurement and again releases the handshake procedure (NDAC is
false and NRFD is false).
- if the Level Meter is to be set to a specified initial status by the
IEC Bus corrmand "device clear (DCL or SOC = Selected Device Clear)".
Again, the interface logic interrupts the handshake cycle and it remains interrupted until the microprocessor has set the Level Meter
to the initial state, when the handshake cycle is again released
(NDAC is false and NRFD is false).
If the strap CLR is fitted on the interface board, the signal IFC
(Interface Clear) causes the Level Meter to be initialized. This permits the Level Meter to be initialized at any time via the IEC Bus,
even in the case of a lock-up situation. (This is important for devices in unmanned stations where a lock-up situation resulting from external interference cannot be cleared by switching the a.c. line voltage off and on again).
4-38
4.20.1.2 Structure of the Interface Bus (IEC 625) Prograrn
Reasons for IE C bus
interrupt
yes
Remote control
on
}
lolonopl
block keyboard
yes
Remote control
off
}
lolonopl
release keyboard
yes
Initialization
program
}
Set-up defined
initio I status
yes
Listener
program
}
Accept byte from
transfer register
(release HS)
Process byte
}
yes
Trigger
program
Sol "ooll moo.odoo"
Start measuring
Remote control
t
local switching
IEC bus command
device clear
-{
b'"
-{
waiting for transfer
Lh,.oo;
IEC bus command
device trigger
-{
To lker byte is
-{
to be presented
yes
Talker
program
sequence
Reset 11 unit measuring 11
SetTSV
} Edll
b,,.
Write byte into
transfer register
(start HS)
Wait for next
interrupt
4-39
4.20.2
BUS SPECIFICATION AND BUS PLUGS
Up to 15 devices can be interconnected in an IEC Bus compatible automatic measuring system. The devices are connected in parallel via the
standard interface.
Each single device is connected to the Bus via a connection cable
with a maximum length of 2 m. The total length of the bus must not exceed 20 m. Greater lengths can be implemented by means of interposed
interface couplers (by a two-wire or four-wire connection) or modems.
The ISO 7-bit code or ASCII code is used on the interface and is
transmitted bit parallel and byte serial.
The pin assignments of the bus plug on the Level Meter are shown in
Figure 4-11. The most important difference between the ~625) and
the IEEE 488 interface is in the construction of the plug (IEC: 25 pin
Cannon plug; IEEE: 24 pin Amphenol plug) and in the pin assignments.
However, test equipment with IEC connections can be connected easily
to the controllers with IEEE interfaces by using the adapter plug
S 834 that is included with delivery of the interface board.
13
~
0105
0106
0107
0108
0105
0106
0107
0108
-g-[6
§;
cD
Twisted
together
,N~-§
7
.
0
7
~
8
ij
()
.g>
Tw1sted{ 11
.....1 together 12
1
1
11
Tw1sted ~
together(!)
·6,
--0
.....)
Figure 4-11 Pin assignments of the Bus connector on the Level Meter.
4.21
PRINTER CONNECTION
A printer interface BN 905/02 can be fitted in Selective Level Meter
of series B and 1ater for recording and documentation of the measured
results on a printer. The interface is installed on the rear of the
unit, instead of the Interface Bus (IEC 625) card, as describe·d in
chapter 6.
4-40
All printers with the CCITT V.24/V.28 interface can be connected.
Wandel & Goltermann recommends connection of the printer
TREND 800 RO 8
from the supplementary program. The technical data and the versions
of this printer are available in a separate specification sheet.
Initiation of a printer operation can be carried out manually with
pushbutton "LOCAL" or automatically after each measurement. The operating mode and the various print formats are selected on the keyboard
[12]. Further details can be found in the operating instructions for
the SPM-16, series B.
4. 22
MEMORY FUNCTIONS
11
MEM"
A number of fixed frequencies and equipment settings can be stored
and recalled later with the blue pushbutton "MEM". This permits rapid
execution of measurements at frequently used frequencies and equipment
settings. If the Level Meter is switched off, or if the mains supply
fails, a built-in Ni-Cd battery provides the power supplied to the memories, retaining the data for approximately 4 weeks. If it is necessary to retain the parameters and data for longer periods, the EPROM
module BN 874/00.01 can be fitted (see section 4.23). This module is
programmed in accordance with the customer's specifications.
4.22.1
ADDRESS ORGANIZATION
Table 4-3 provides an overview of the addressable memory positions
(address and program numbers) and their contents. As can be seen from
this table, 100 fixed frequencies and 11 complete equipment settings
can be programmed as required. The parameters and data are stored in a
RAM and are not cleared when the unit is switched off (see section
4.22). They can be oven1ritten at any time Hith new entries.
In addition, a maximum of 100 further fixed frequencies and 40 equipment settings can be stored in accordance with the customer's specifications in an EPROM (see section 4.23.1). Numerical inputs of 1000 or
greater are interpreted by the Level Meter as test program numbers for
special measuring or operating modes, such as test programs, or operating programs for connected printers (series B or later).
4-41
The built-in test programs listed in Table 4-4 are stored at the address 115 or 119. After the appropriate address has been entered, the
currently stored program number appears in the level display A as long
as pushbutton "RCL" is depr·essed. When the pust1button is released, the
Level Meter executes the stored test program.
The Level ~1eter can be switched back to a normal test program by depressing one of the display pushbuttons (e.g. 11 ABS 11 ) .
Address
0 •• ., 99
I
I
Remarks
RAM
Fixed frequencies
Freely programmable
After bootstrapping
load * : 0 kHz.
Freely programnab l e
After initial program
load * : standard
I
Equipment settings
(set-ups)
115
RAM
Printer programs
119
RM~
Internal test programs
200 ••• 299
ROM
Fixed frequencies
300 ••• 339
ROM
Equipment Set-ups
I
Table 4-3
Programn
number
5000
9001
9900
9901
...
Table 4-4
*) Note:
4-42
Contents (data)
RAM
100 • • • 110
I
Memory
area
I set-up.
l
}
I
Ij
I
'
I
I
Input vi a program
number as shown in
Table 4-4.
Fixed, as specified by
customer.
Fixed, as specified by
customer.
Address Organization
Memory
area
Contents
ROM
Printer programs (see 4.2.1)
Standard Setup
Test program, dB calibration
Test program, dBm calibration
RAM
ROM
ROM
Program Numbers
The program number 9000 (bootstrap load) should be used only
when actually required (e.g. to clear the fixed frequency
11
11
RAr~), because the Standard Setup clears the contents of
II
addresses 0 to 99 and loads the contents of addresses 100 to
110 as specified in section 3.6. If the power supply for the
RAM from the built-in Ni-Cd battery had been interrupted,
for example during repair, it is reco~nended that address
9000 be also recalled or the pushbutton T below the upper
case cover be depressed. (See section 3.6 and Figure 6-2).
If an attempt is made to store or recall fixed frequencies or equipment settings at false addresses. an error number (e.g. 2--001
false
address number) appears in the frequency display D. The meanings of
the error numbers are shown in Table 6-2.
=
4.22.2
THE FUNCTIONS STORE AND RECALL
Data and measuring parameters can be stored and recalled as required
with the two pushbuttons "STO" and "RCL" on control panel [12]. After
entry of the values, the following pushbuttons must be depressed:
Store:
"MEM"
address number
"STO"
The LED above the pushbutton "MEM'' blinks as long as the
function key "STO" is not depressed. An error number appears
if a false address is selected (see section 4.22.1).
Recall :
"MEM"
address number
"RCL
II
The LED above the pushbutton "MEM" blinks as long as the
function pushbutton "RCL" is not depressed. An error number
appears if a false address is selected (see section 4.22.1).
After a successful recall, the MEM function remains active
and further addresses can be entered via the keyboard [12]
or the addresses can be stepped sequentially by depressing
the two directional pushbuttons L. Automatic stepping is
possible in the address ranges 0 to 99 and 200 to 299.
When the MEM function is active, the selected address number is displayed in the frequency display D as long as the pushbutton "RCL" is
depressed.
4-43
4.22.3
STORING THE FIXED FREQUENCIES
Number: Up to 100 fixed frequencies
Address range: 0 .•• 99 (see Table 4-3).
-Enter the required frequency on the keyboard (see section 4.4.1).
- Depress 11 MEM" (LED must 1 i ght).
- Enter the required address en the keyboard [12]
- Depress "STO"
- Enter the next frequency.
If it is necessary to enter a large number of fixed frequencies in
sequential addresses, remembering of the last address which was used
can be avoided by using a different input procedure, as described
below:
Enter first frequency - 11 MEM" - on - enter starting address - "STO" "MEM" on - Step V - "r1EM" off Enter second frequency - ~~~1EM" on - "STO" - "MEM" on - Step
4.22.4
V
etc.
RECALLING ANY, SINGLE FIXED FREQUENCIES
from the address ranges 0 ••• 99 and 200
299
(with auxiliary device BN 874/00.01 only).
- Depress "MEf'-'1".
- Enter the required address (frequency) via the keyboard [12].
- Depress "RCL". The required fixed frequency appears in the frequency display.
As the MEM function remains
recalled immediately simply
4.22.5
further fixed frequencies can be
entering the address.
active~
by
RECALLING A SEQUENCE OF FIXED FREQUENCIES
If measurements are to be carried out with several frequencies, which
are stored as sequential addresses in the RAM. settings can be simplified considerably by manual or automatic recall.
a) Manual recall
Select the required starting address (frequency) as described in
Section 4.22.4.
4-44
-The following fixed frequencies are then selected with the two
STEP pushbuttons l} ~. The function MEM remains active. The
corresponding address number is displayed if the pushbutton "RCL"
is depressed.
b) Automatic recall
In this mode, the start and stop addresses (frequencies) must be
specified. Measurement is then always carried out within the preset
limits. This mode is used> for example, for selective end-to-end
line measurements (see section 4.11).
- Depress "MEM''.
- Depress "fsTART" and enter the start address on the keyboard
[12]1).
- Depress
Depress
- Depress
-Set the
- Depress
"RCL".
"fsrop" and enter the stop address via the keyboard
[12].
"RCL".
STEP TIME with changeover switch [17].
"STEP 11 twice (LED "AUTO" must 1i ght).
Measurements are now carried out cyclically between the start and
stop addresses. After each cycle, the STMS starts again at the start
address. Depending on the settings, the frequencies are stepped in ascending or descending order of addresses. If the a.c.line power is
interrupted and switched on again, the STMS switches back to the old
operating state.
Switching Off
of the automatic address stepping: depress a function pushbutton such
as "f" and depress pushbutton "MEM''.
4.22.6
STORAGE OF EQUIPMENT SETTINGS (SET-UPS)
Number: up to 11 complete front panel set-ups.
Address range: 100 ••• 110 (see Table 4-3)
1) If EPROM BN 874/00.01 (auxiliary device) is fitted, the error number 2--004 may be displayed at the transition from the ROM address
range to the RAM address range (or vice versa). This will disappear
as soon as a stop address is entered.
4-45
2'
With the exception of the two functions 1 AUTO STEP and TRACK, all
functions and parameters which can be selected on the front panel can
be stored. Storage and recall is carried out as described in section
4.22.2:
- Input of the required parameters and data.
-Depress "MEM" (LED must light).
- Select the required memory position (address) on the keyboard [12].
- Depress "STO".
- Enter the next equipment setting.
4.22.7
RECALL OF EQUIPMENT SETTINGS (SET-UPS)
from the address ranges 100 ••• 110 and 300 ••• 339 (with Auxiliary
Device BN 874/00.01) is carried out as described in section 4.22.2:
- Depress "MEM''.
- Enter the required address (set-up) on keyboard [12]•
- Depress "RCL".
As the MEM function remains active, further set-ups can be recalled
by simply entering the address or with the aid of the bto STEP direction pushbuttons "L'' (see section 4.22.5 a) (see also remarks 2 )
under 4.22.6).
This facility has an interesting application for sweep frequency
measurements. ~lith the aid of the STEP direction pushbuttons L, it is
possible to display in consecutive order the overall selectivity and
the pass-band of a filter on the screen of a display unit.
4.23
FIXED VALUES MEMORY (AUXILIARY DEVICE) BN 874/00.01
The memory module permits the additional storage of up to 100 fixed
frequencies and 40 complete front panel settings. The required frequency values and equipment set-ups should be specified when ordering
auxiliary device BN 874/00.01 in order to avoid delivery delays (see
section 4.23.1).
2) AUTO STEP and TRACK functions are possible if, after recall of the
required set-up, the start and stop addresses are entered as described in 4.22.5 b.
4-46
4.23.1
FIXED FREQUENCIES AND EQUIPMENT SET-UPS
The fixed frequencies and equipment set-ups specified by the customer
are permanently stored, as shown in Table 4-3, in
Address area 200
Address area 300
299 for fixed frequencies
339 for equipment settings.
They are recalled as described in section 4.22.2 to 4.22.7. If the
EPROM BN 874/00.01 is not fitted in the meter, an error number (e.g.
2--001 =false address number) would appear in the frequency display
D. The meanings of the error numbers are explained in chapter 6.
The ordering forms No. 5/798a for equipment settings (Part I) and/or
No. 5/798b for fixed frequencies (Part II) must be filled out comple~ vihen ordering the EPROM. Figures 4-12 and 4-13 shows samples of
these ordering instructions; column 1 of the ordering instructions for
instrument setting contains an example of the entries.
If more than five equipment settings are required, further forms No.
5/798a should be used, and the pages of the form numbered sequentially. Please enter~ level and frequency values, even if they are not
always required.
4-47
Please 1111 out cornpletely w1thm th1ckly drawn
Ausstel!er b1tte 'lur d1e star...:: umranderen Ft>lder vo!lstand1g ausfu!len
I
SPM-16
Option BN 874100.01
Bestellvorschrift
Ordering Instructions
I
frame~
Blatt
Sheet
Nr
I
Teill I Part 1: Geratee1nstellungen /Instrument sett1ngs
Kunde I Customer
1
Besteii-Nr. I Order No.
~------------~-.------~--------~r-----------------~------------------I
SPM-16. Nr.:
1
AB:
gepruft·
I'
erstellt (Datum)
f---ch_e_c_k_e_d___ --j-"ompleted (date)
T:
Festfrequenzen I Fixed Frequencies (Tell II I Part II) jalyes
I
0
0
ne<nl no
I
Gewunschte Einstellungen und Zahlenwerte 8 eintragen. Mit AdreBnummer 300 beginnen (Max. bis Adresse 339): bei >5 Setups weitere Vordrucke verwenden
Enter wanted settin!JS and numerical values. Beg1n w1th address No. 300 (Max to address 339): with >5 Setups, use another printed form.
Adresse I Address
Display:
Beispiel I
Example
No.
Abs
[ill, Ref [I]
[l]
(2]. dBr@]
0
0
0
0
0
0
0
0
0
0
m
0
0
0
0
0
0
0
0
0
0
(2]
0
0
0
0
0
0
0
0
0
0
0
tAbs-Ref)
dBmO
Digital
Mode·
ITJ
Analog 1 dB [ill
(Scale)
[!], 80 dB (l]
20 dB
<t>[§J
Averag<ng:
On
Auto Cal
On
ITJ, OH [ill
[ill, OH ITJ
[ill
Wide [ill
Bandwidth·
ITJ[l]
(2]
lil
[§]
Sel. 25,400,1740,3100 Hz,4SkHz
l:::::o,.
Demod:
Phase Jitter
AFC
On
L::'][IJ
[§],
[I], Off
IQ],
Coarse
ITJ
Search
~
rg:l
<],
(2]
Sweep
oN
@:1
__/~
[§]
Opt 31
[ID
Cantin: Man Fine
Ratels
[ill
0,3
MeBbereich I Meas. Range
,
• I~ ala
!''•• -Ia ~I
I
• I It
fsTART
}
6)
fsTEP
_,
0
0
0
0
•
•
•
i kHz
Hz
I
I
0I 0
!
MHz
I
1617jsj91olo o
11 1o1o o
kHz
1
Hz
MHz
i
':
I 'Hz
I
I
I
I
i
l
0
,,
Hz
I
I
I
I
I
iO
i
1olo
MHz
kHz
o:o
I
Hz
i I
II :I
II
I
.,
i
I
I
I
I
I
MHz
I
1
!
Ilolalo
Hz
kHz
I
I
MHZ
4) Nur Zahlenwerte eintragen
5) Bei Frequenzabl3ufen Anfangsfrequenz eintragen
6) Hier stets einen Zahlenwert eintragen, auch wenn Set-up ohne Wobbel-
Ordering Form No. 5/798a
Hz
I
I
I
i
I
I
4) enter numencal values only
5} enter beginning frequency w1th frequency run
6) here. always enter a numerical value. even when Set-up without
o
I
I
1) The functions AUTO and TRACK are only callable manually
2) enter additionally with SWEEP 5
3) '1n SEARCH-SCAN mode, additionaily enter w1th SWEEP 5 (1f -N
sweep- or fsrEp-function
oder fs;Ep-Funktion
kHz
I
1
I
0 0
!
I
I
II
1,
or6(if~)
eintragen
i !I
i
i
I
iI
I
I
I
1) Die Funktionen AUTO und TRACK sind nur manueli aufrufbar
4-48
I
I
Io
I
1
I
I
2) zusatzlich bel Sweep 5 eintragen
3) lm Suchlauf zusatzlich bei SWEEP 5 (wenn w) oder 6 (wenn _/)
Fig. 4-12
:
I
2j3 4i5 6
1
I
0
1
1111213 415 6
1
0
_,I
1 0 0
0 0
MHz
Frequenz I Frequency f Si
0
0
1
Ref-Wert I Value
dBr-Wert/Value
0
[§]
I)
0
Man 21
fsTOP
I
rnJ
c~
\.
)
I
I
Please 1111 oul completely wJthtn li11ckly
l
SPM-16
Bestellvorschrift
Ordering Instructions
Option BN 874/00 01
Teill/ Part I Geratee1nstellungen I Instrument settings
1 - - - - - - - - - - - - ' - - . . . - - - - - - - - - - - - - - - 1 - - - . ~·-
I
i
N r. :_j___ ~ _
Kunde I Customer
~----t··
AB:
SPM-16 Nr
gepruh
checked
ers1ellt (Datum)
completed (date)
'--------·--------
r1ra~
----r.
·
J
l fram1
Bl< tt
Sh "e
Besteii-Nr I Order No.
----------··-·---------
1
i
l
T:
Festfrequenzen 1 Fixed Frequencies (Teilll I Part II) 111 I yes
Q
--
nt>rn/ n< ( )
Gew(inschte Einstellungen und Zahlenwerte e eintragen. Mit AdreBnummer 300 beginnen (Max. bis Adresse 339): bei >5 Setups weitere Vordrucke verNer :1en
Enter wanted settings and numerical values. Begin with address No 300 (Max. to address 339); with >5 Setups. use another printed form
~------~---------,--~~~77--~------------~----------~------------~-----------,--------~
Beispiel/
j
Adresse! Address
No
Example
Display
Abs
[Q].
Ref
OJ
D
(Abs-Ref)[Ij
dBmO
Mode
@), dBr GJ
Digital
On
III, Off [QI
Auto Cal
On
[Q].
IT! liD
GJ
@]
l::::::,
Phase Jitter
On
[ill.
[Q]
m
OJ
D
D
D
0
D
[]
[]
D
0
D
0
Sweep
""" ffiJ
Rate/s
Man
21
[Q]
_,F
[]
0
D
•
•
Ref-Wert I Value
dBr-Wert 1 Value
Frequenz I Frequency f
jSTART
6
~
ia
~
I
•
•
•
•
•
D
•I
•I
•I
I
1
0 0
0
1
I
kHz
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1) Die Funktronen AUTO und TRACK sind nur manuel! aufrufbar
2) zusatzlich bei Sweep 5 eintragen
3) lm Suchlauf zusatzlich bei SWEEP 5 (wenn w) oder 6 (wenn _/)
eintragen
4) Nur Zahlenwerte ein\ragen
5) Bei Frequenzablaufen Anfangsfrequenz eintragen
6) Hier stets einen Zahlenwerteintragen, auch wenn Set-up ohne Wobbeloder fsrEp-Funktion
1) The functions AUTO and TRACK are only callable manually
2) enter additionally with SWEEP 5
3) in SEARCH-SCAN mode. additionally enter with SWEEP 5 (if'-')
or6(if~)
4) enter numerical values only
5) enter beginning frequency with frequency run
6) here. always enter a numerical value, even when Set-up without
sweep- or fsrcp·function
L-----------------------------------------------------------------------------------------------------~
Aussteller bitte nur die stark umrandeten Felder vollstandig austullen
m
Orderer: P!e3so ftll out compleieiy w1Hm1 ih1ckry 1)ra~ n tram
SPM-16
Option BN 874100
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Bestellvorschrift
Ordering Instructions
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Bestellvorschrift
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Option BN 874/00.01
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Besteii-Nr 1 Order No
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Ordering Form No. 5/798b
4-49
4.24
MEASURING ACCESSORIES
4.24.1
TEST PROBE TK-11
The Test Probe TK-11 is designed for high impedance and low capacitance extraction of the test signal from test objects with coaxial
connections. The Test Probe is connected to input socket [19] (measured signal) and the test probe socket [18] (power supply).
As soon as a plug is inserted in socket [18], the 10 dB insertion
loss of the Test Probe is compensated by a corresponding sensitivity
increase within the Level Meter.
In the most sensitive measuring range of -120 dB or -110 dBm (analog
mode), the range indication switches to -110 dB or -100 dBm.
Figure 4-14 Test Probe TK-11
The test prod shown in Figure 4-14 can be replaced by a coaxial socket
element S 222 of the Versacon ® 9 system.
Adapters for all common connection systems can then be screwed into
this element. User of the Versacon element increases the input capacitance of 3.5 pF specified in section 1.11.1 by a value which varies
according to the type of connector.
The maximum permissible input level of the TK-11 is +10 dBm or +2 dB;
any superimposed DC voltage must not exceed 50 V.
4-50
ADAPTER FEDA-1 (75 0/50 0)
The internal
impedance of the uenerator output
of the receiver input can be matched to
dn
<W
th<~
input irnpecl.lJle<'
i :npedance of
~0 Q
\vi til the
adapters 75 0/50 Q. The available socket adapters are listed in section 1.12.3.
If a 75 Q cable is used as a test lead, then the adapter should be
inserted at the end close to the object being tested (see Figure
4-15). If a 50 Q cable is used, it should be fitted on the level meter
inside.
8
_
5 16
7_512--~7755
/1
""~/"' _soJ
__
"-~;..;
_ ...
---,
Test obJect
z = so 12
,_
..-
K7Sf7s
~_
lso ~
L;.~»
7512
-BPM-16 :::'
""·
0:>
~75Q/50~ adapters~
Figure 4-15 Measuring at an impedance of 50 Q.
When setting up the generator output level or when reading the level
indicated on the receiver, the attenuation (2 x 6 dB) of the adapter
must be taken into account. With the combination PS-16/SPM-16, this
can be done very easily by transferring the attenuation value to the
memory for the reference level (dBr) (see sections 4.6.1.2, 4.6.1.3).
The error limits of the level generator and level meter listed in the
specifications may be increased by attenuation and frequency response
errors and by the reflection factor of the adapter.
4.24.3
REFLECTION AND SIGNAL BALANCE RATIO MEASUREMENTS
Various measuring adapters are available for these measurements:
Reflection measuring unit RFZ-5, 10 kHz to 36 MHz (see description
and operating instructions, RFZ-5).
Reflection factor measuring bridge RFZ-14, 100 kHz to 100 MHz.
4.24.3.1
Reflection Loss Measuring Adapter RFZ-14
The measuring bridge RFZ-14 permits measurement and sweeping of the
frequency dependent reflection loss on CF transmission systems or
single modules. Together with a generator (PS-16/PSS-16) and receiver
(SPM-16) such measurements can be carried out in the frequency range
4-51
100 kHz to 100 MHz. The reference impedancer is 75 Q. The interchangeable socket inserts can be adapted to all common connection systems
(see also chapter 6).
Level generator
Level meter
8------<11--6------~--B ~
~
Test object
Figure 4-16 Connection of the measuring bridge RFZ-14 to the level
measuring set-up.
The measuring adapter is connected to the generator output and the receiver input with 75 Q cables, as shown in Figure 4-16. The generator
output level should be as high as possible, but should not exceed the
maximum permissible level at the input to the object being tested by
more than 6 dB (overload limit).
The test configuration is calibrated at the required test frequency
or, in the case of sweep operation, within the sweep range. For this
purpose, the bridge must be disconnected from the object to be tested,
resulting in a reflection factor r = 1 or a reflection loss a
r
0 dB. The voltage-linear display is selected on the level meter SPM-16
with the pushbutton 11 20 dB 11 • If major variations of the reflection
loss are to be expected, for example in sweep mode, then the level-linear 80 dB display is better. The value displayed on the meter B corresponds to the reflection loss a = 0 dB. It is recommended to adr
just this value to 0 dB on the meter scale by changing the measuring
range setting [9] on the SPM-16 and the output level of the generator.
After connection of the object to be tested, its reflection loss results in a different level from that previously displayed. The measuring bridge is connected directly to the object to be tested in order
to avoid additional measuring errors resulting from long cables, possibly with inaccurate characteristic impedances (75 Q).
4-52
[-~xamp "j
e:_
Indicated level on receiver for calibration and after
correction of the generator level (reference value) •••.•••• -20 dBm
Indicated level with object to be tested
connected to RFZ-14 (measured value) ••••••••••••••••••••••• -46 dBm
Reflection loss (reference value minus measured value •••••••• 26 dB
Corresponding reflection factor •••••••••••••••••••••••••••••••• 5%
4.24.4
RE0-50 AND RE0-56 MATCHING TRANSFORMERS
For simultaneous connection of the SPM-16 level meter and another receiver (e.g. REB-56 wide band levelmeter or RE-5 white noise receiver
in the RK-5 white noise measuring set-up) matching transformers RE0-50
and RE0-56 are provided at a system point (see Fig. 4-17). They are
both transforming dividers with bridging-type input and two outputs
decoupled from one another and from the input whose level is 20 dB be-
r--,
...-----t.(-
- ) lI
-;-
p
L-
RE- 5
REB-561
Llor__
similar.JI
_..J
-
p- 20 dB
REU- 50/56
-
-
r--------4(---
p
z =75 rJ
-c:J----f
p
r--,
I RE- 5 I
I REB-56 i-<-------1 or __
similarJI
p~B
._
-
p-20 dB
-
____
SPM -16
REU- 50/56
Fig. 4-17 Application of RE0-50 and RE0-56 matching transf.
4-53
!:::
..,-J
.....
low the input level. The RE0-50 operates in a frequency range between
50 kHz and 14 MHz and the RE0-56 in one from 300 kHz to 60 MHz.
The two transformers are also suitable on account of their bridgingtype input for setting decoupled measuring points on systems in operation.
4.24.5
TWO-WAY DIVIDER REV-56
Another alternative for connecting the SPM-16 level meter and another
measuring device with a 75 Q input at a system point is provided by
the REV-56 two-way distributor (see Fig. 4-18). It consists exclusively of resistive components and, therefore, has very wide band
application. The attenuation between its three connections is 10 dB in
each case. If an output is not in use it should be terminated with a
75 Q resistance.
REV-56
Fig. 4-18 Possible connection using the REV-56 two-way distributor
4-54
5
ME A S U R I N G N 0 T E S
5.1
SELECTIVITY CURVES OF THE LEVEL METER
Figures 5-1 and 5-2 show the overall selectivity of the Level Meter
for the selectable bandwidths 3.1 kHz, 1.74 kHz, 400 Hz and 25 Hz.
These figures show typical selectivity curves of a standard production
instrument.
!
a
70
I 400Hz~
iI
dB
60
J-----~T-
~
~
~
I
I
+-r
1,7L. kHz
-+
v:::I
I
3.1 kHz
I
50
--
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----
i
I
I
40 -~--r-
I
!
I
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30
10
\
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-2
0
I
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--
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+2
+4
Llt
Figure 5-l
-
kHz
Typical selectivity curves for the bandvvi dths
400 Hz, 1.74 kHz, and 3.1 kHz.
5-l
I I I
I I
I
1
a
r ~
/1 ~y
--T
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60
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--~-----l------
__,
,..._
0 ~--~------+-------~-------+------~--~~
-100
0
+100
+200 Hz
·-200
Llf -----Figure 5-2
5-2
Typical selectivity curve of the Level Meter
with 25 Hz bandwith.
5.2
MEASUREMENT OF HIGH ATTENUATION VALUES
In the case of level measurements on two port nchwr·ks with hi<Jh attenuation values, a high return impedance Z between the generator
s
and receiver of the measuring set-up is necessary (see Figure 5-3). If
the return impedance is not infinitely large, the voltage drops across
the ground line resistances r and r of the test cables used
1
2
cause additional measuring errors. In order to keep these small, Z
s
must be large with respect to r 1 and r 2 for practical applications. In the SPM-16, a high return impedance was achieved through
decoupling the ground of the measuring circuit from the chassis ground
by a coaxial choke.
The effects of the above-mentioned resistances on the still measurable attenuation are described in the following section.
The object to be tested is a two port network with an infinitely
large attenuation. Zs is the return impedance, r 1 and r 2 are the
unavoidable ground conductor impedances 1 ), which can also be complex
just like Zs. The voltage drop resulting from the generator current
through r 1 causes a voltage to exist between the chassis of the generator and the receiver.
If the return impedance Z is finite, a signal current flows
s
through r 2 , causing a signal voltage at the receiver input and simulating a finite attenuation of the object being tested.
1)
r and r are often called "transfer impedances" in coaxial
2
1
cables, plugs, etc., and are defined as follows:
Transfer impedance =
Voltage drop on the outside of the outer conductor
Current on the inside of the outer conductor
Transfer impedance
=
Voltage drop on the inside of the outer conductor
Current on the outside of the outer conductor
5-3
A simple calculation, assuming that r
spect to zout' zin'
v2
vo
. ~ .
r1
zout
z and
+
z zs
In the case wher·e zout
20 dB
a
~
and r
2
are small with re-
zs' shows
2; n
z.1n
z.1n
log
20 dB
1
1og
z
+
z.
the image attenuation is
v0
2
v2
2
z zs
r,
.\.
r2
For a maximum measuring error of 0.01 dB, for example, this attenuation must be approximately 60 dB (approximately 40 dB for 0.1 dB)
greater than the attenuation to be measured if the worst case is assumed for the phase angle between the measured voltage and the error
vo 1tage.
The return impedance Z is approximately 40 Q, starting at 300 kHz.
s
If r and r 2 are assumed to be at 10 mQ each - this is the value
1
of the transfer impedance of a good, double-screened coaxial cable
with a length of 50 em - then the image attenuation with Z = 75 Q and
Z
40 Q for the configuration shown in Figure 5-3 is 156 dB.
s
With a measurable attenuation of, for example, 96 dB with a Test Setup PS-16/SPM-16, the value of 156 dB calculated under the above
assumptions leads to a maximum additional error of 0.01 dB.
PS-16{PSS-16)
,-----,
1
RI(Zout)
1
l:
I
uol
L __ _...___,
Figure 5-3
5-4
SPM-16
r-----~
I
I
I
I
5.3
MEASUREMENTS OF IMPULSIVE NOISE AND INTERRUPTIONS
Measurement of the parameters phase jitter, imp11lsive noise, and interruptions are becoming more and n~re important for assessing the
transmission quality of telephone lines for data communications. Impulsive noise and interruptions cannot be measured directly with the
SPM-16, but it can be used together with the demodulator for conversion of single voice channels or measured signals from the CF frequencies to the AF range. In order to avoid measuring errors, particular attention was paid to ensuring that the modules which participate
in conversion into the speech channel have, as closely as possible,
the characteristics of CF channel converters. For this reason, the
Level Meter also has the bandwidth of 3.1 kHz, which corresponds to
that of a telephone channel. For faithful reproduction of the voice
channel, the Level Meter must be tuned to the center of the CF channel. The demodulator output is characterised by a wide dynamic range,
which is necessary for impulsive noise measurement (see section 4.8).
The two performance characteristics mentioned above can be measured
with external devices (e.g. OLM-3). For interruption measurements, the
converted 2 kHz signal can be extracted at the demodulator output if
the SPM-16 is tuned to the carrier frequency measuring tone. Due to
the excellent level and frequency stability of the Level Meter, longterm measurements can also be carried out.
5.4
PSOPHOMETRIC WEIGHTING OF NOISE VOLTAGES
It is a well-known fact that the sensitivity of the human ear is frequency dependent. For objective simulation of this property the psophometric filter is used to simulate this frequency response, including the transmission characteristics of the handset (Figure 5-4).
This permits correct weighting of the noise existing in telephone
channels.
If, however, the noise within a telephone channel is "white'', which
may be assumed in the case of CF transmission, the psophometric filter
can also be replaced by a flat band-pass filter which has the same effective bandwidth (see Figure 5-5). The Level Meter is equipped with
the bandwidth of 1.74 kHz for this purpose.
5-5
0,3
Figure 5-4
0.4
0.5
0,6
0,7 0,8 0.9 1
1,5
2
kHz
3
3.4
Psophometric curve
(~
u,
Figure 5-5
Selectivity curve and effective noise bandwidth.
The SPM-16 uses a true rms value meter, calibrated so that the indication for the rms value of a sinusoidal voltage is practically equal
to the effective value of the white noise.
The drive levels for the complete signal path, including the rectifier circuit, are selected so that precise noise measurements are possible (crest factor 12 dB).
5- G
5.5
AUTOMATIC DRIVE LEVEL MONITORING
In order to increase the measuring accuracy, some modern level meter·s
have facilities for the operator to select either of the modes low
noise or low distortion. With the aid of this control, the gain in the
wide-band input stage preceding the first mixer and in the intermediate frequency section after the last conversion can be varied in a
specific ratio, while maintaining the same overall gain. However, this
solution is a compromise and can cause confusion and errors if the
signals are unknown. The Level Meter SPM-16 with its built-in microcomputer offers an optimum solution to this problem, as it automatically selects the roost favorable instrument drive signal levels as a
function of the wide-band loading present at the test input. To do
this, the wide-band gain is increased step-by-step and the microprocessor checks the IF level for non-linear components. As soon as these
are detected, the wide-band gain is reduced by one step, so that there
is again a linear relationship between the input and output levels.
This principle ensures that incorrect settings are not possible and
always guarantees the highest possible measuring accuracy.
5-7
6
F U NC T 0 NA L T E S T I NG ,
MI S C E L L A N E 0 U S
MA I N T E N A N C E ,
A N0
The following information is provided to permit correct function of
the Level Meter SPM-16 to be checked. This permits the user to determine whether the unit has any major defects (such as could result from
transport damage). A test of ail functions is carried out as described
in section 6.1 when the SPM-16 is switched on for the first time. A
functional test of the most important ~~dules (in hardware self-test)
can be carried out as described in section 6.5.2.
6.1
FUNCTIONAL TEST WHEN SWITCHING ON FOR THE FIRST TIME
The functional test is carried out when the SPM-16 is switched on for
the first time. The cable connections shown in Figures 3-3 and 6-1
must be provided for this test. The test is carried out in the sequence specified in Table 6-1, Pages 6-2 and following.
f=10MHz
tr=?~
I
I
Level meter
Demod.
I
y
0 0 0
L_]OTI
'
X
0 0 0
I/
'r'
Digital
voltmeter
Figure 6-1
ACV
ocv
Test configuration for the functional test
6-1
REACT I 0 N
!ACTION
I Pushbutton
or setting
Level of frequency display, LED
I
kHz
Unit set to standard set-up: f = 100.000 kHz, ABs,l
ANLG, 20 dB scale, bandwidth 3.1 kHz (the stan- I
dard set-up is a 1so transferred to the memories
for front panel settings, addresses 100- 110).
l;
MEM, 9001'
I
I
I AUTO CAL
Red LED lights above AUTO CAL
f = 10234 kHz
Frequency display:
f = 6.78 MHz
I
0
CLR
kHz
kHz
kHz
kHz
4.000.000 kHz
1.000
8.000.000
12.000.000
10.000.000
f STEP
I fSTART
fSTOP
= 8 MHz
= 12 MHz
fCENT
I
df
MAN
LED
Turn knob
ITurn knob
[14]
~lAN
f =
[14 J
I
10 kHz
v
STEP
{7
STEP
11
FINE" lights
Frequency change in 1 Hz steps
LED 11 COARSE" iights
Frequency changes in 100 Hz steps
Frequency display:
10.000 kHz
11.000 kHz
10.000 kHz
I
"TRACK lights
STEP
LED
STEP
LED "AUT0 11 lights. Frequency steps by 1 kHz per
I second.
SWEEP
J
I
s·~~EEP
N
I
fSTOP
Search
fSTART
I
I
ll
'(/
I
u'""
Search
SWEEP
I
I
I
I
Svvitch [17] to OPT
6-2
10.234.000 kHz
6.780.000 kHz
N
I
II
Table 6-1
I
Frequency sweeps from 8 MHz to 12 MHz or vice
versa.
Units sweeps between 8 MHz and 12 MHz
I!
I
Frequency search towards lower frequencies and
stop at 10 MHz.
Frequency search towards higher frequencies
and stop at 10 MHz.
I!
Frequency search between 8 and 12 MHz and stop
at 10 MHz.
Restart by depressing the pushbutton IISWEEP 11
Sequence of functional test
I
l
I'
I
N I
I
i
ACT I 0 N
I
Select all positions
1'/i th SV/i tch [17]
I Corresponding
I
f = 9.9985 MHz
AFC
I
REACT I 0 N
LED lights.
Frequency display:
9.998.500 kHz
10.000.000 kHz
A.FC
AUTO CAL
Signal detector lights.
LED alongside AFC is switched off.
Red LED is extinguished
Depress pushbuttons ASS
and REF simultaneously
(ABS-REF)
Level display: approx. -2 dBm/-12 dB
Level display: 0 dB, meter: 0 dB
80 dB scale
Level display: 0 dB, meter: 0 dB
LED on 80 dB scale of meter lights.
20 dB sea 1e
LED on 20 dB scale of meter lights.
1 dB scale
LED on 1 dB scale of meter lights
Meter indication: 0 dB
Select bandwidth 1.74 kHz,
400 Hz; 25 Hz and WIDE
Corresponding LED lights.
Meter indication: 0 dB (vJIDE: 0 dB + 0.1 dB)
Indication: 0 dB
2-kHz-tone audible (if necessary, adjust
volume [20])
I Position
I
~
I
¢p-p
Bandwidth 3.1 kHz
20 dB scale
Depress pushbuttons ABS
and REF simultaneously
(ABS-REF)
Select measuring range
20 dB with switch [9]
A.UTO SET
LED on 0-scale of meter 1 i ghts.
Indication approx. 0.3"
Indication 0 dB
Meter indication: -20 dB
Meter indication: -5 dB
~leasured 1eve1: (5-5) dB
Table 6-1
I
= 0 dB
Sequence of functional test (continued)
6-3
!REACT
!ACTION
I
ON
OGTL
Leve1 indication: 0.0 dB
AVRG
Level indication: 0.00 dB (2:_0. 02 dB)
REF
Level indication: approx. -2 dBm/-12 dB(reference
1eve l )
dBr
level indication: +0.0 dBr (relative 1eve 1 )
dBr
LED alongside KEYBOARD ENTRY lights
'
I
The level indication is entered \'lith a
Enter the previously displayed reference level (REF) resolution of 0.1 dB.
as a relative level via [12 J
I
1
I
I
II
I
I
Entered level is displayed in dBr
LED alongside KEYBOARD ENTRY is switched off.
Terminate the input with
pushbutton -dBr or +dBr
(+/- according to reference l eve 1 )
Level indication: 0.00 dBmO/dBO +0.1 dB
(related level)
dBmO
!
I
Connect digital vc ltmeter (ACV) to demodulator output [21]
ISvlitch
demodulator~ on.
AC voltage at output: approx. 1.5
v
Connect digital voltmeter (DCV) to Y-output [22]
Depress ABS and REF simultaneously (ABS-REF), ANLG
Adjust range switch [9]
for 0 dB indication on
meter
DC voltage at Y-output: 4
v -+ 50 mV
I
Connect digital vc 1tmeter (DCV) to X-output [23]
f
I
ST?.RT
fSTOP
Table 6-1
DC voltage at X-output: -2.5 V -+ 50 mV
DC voltage at X-output: +2. 5 V -+ 50 mV
Sequence of functional test (continued)
Further tests are carried out as described in sections 6.1.1 to 6.1.3.
6-4
6.1.1
CHECKif'lG THE
INTERNAL NOISE
Settings on the SPM-16:
- Coaxial input [19] has no test signal applied
-Select digital mode with pushbutton "DGTL" and display of the absolute level with pushbutton "ABSu.
- Select bandwidth 3.1 kHz with changeover switch [16].
- Tune the Level Meter to 2 ~iHz vtith keyboard [12] (see section
4.4.1).
Maximum measured values:
for bandwidth 3.1 kHz
for band~·Ji dth l. 74 kHz
for bandv1i dth 400 Hz
for bandv1i dth 25 Hz
6 .l. 2
Noise
Noise
Noise
Noise
1eve l -127 dB
(-118 dBrn)
l eve 1 -129 dB
l eve 1 -135 dB
level -139 dB
(-120 dBm)
(-126 dBm)
(-130 dBm)
CHECKING THE RECEIVER SELECTIVITY
Settings on the SPM-16:
As in section 6.1, but
Enter frequency f == 10 MHz via keyboard [12] (see section 4.4.1).
- Connect the 10 MHz standard frequency (socket [50] on rear of unit)
to test input [19].
- Depress pushbuttons "ABS"and "REF" simultaneously.
- Depress pushbutton "ABS-REF"; indication is 0.0 dB.
- Depress pushbutton "fSTEP" and enter 2 kHz on keyboard (12] (see
section 4.4.1).
- Depress pushbutton "f"; indication is 10 MHz.
- Change the tuned frequency up or down by one step (~ 12 kHz) with
pushbutton "STEP" 1} or ~7 and read the level display.
Attenuation compared with the reference value ~45 dB. These values
are also true for the 1.74 kHz and 400 Hz bandwidth. For the 25 kHz
bandwidth, the attenuation must stay ~ 60 dB. at an offset fSTEP ;
.2:_250 Hz from the center of the band (10 MHz).
6 .1.3
FUNCTIONAL TEST OF THE CALIBRATED ATTENUATOR
- Generator output [44] -15 dBm, connected to rear panel Receiver
input [19].
6-5
-Settings on SPM-16: "ABS, ANLG", 80 dB scale range, "AUTO CAL OFF"
(red LED illuminates),~ (Den10d.) (in this position only the Wlfli:.BAND gain changes),
f = 10 MHz
- Switch through measuring range with switch [9] in 5 dB steps from
+30 1 ) to -20 dBm (+20 to -30 dB), and check analog meter to determine whether or not the reading changes in 5 dB steps from -45 to
>+2 dB (-44 to >+2 dB).
If a 20 dB attenuator is connected ahead of the Receiver input [19],
then the calibrated attenuator can also be tested in the measuring
ranges, -25 and -30 dBm (-35 and -40 dB). In the measuring range +30
to -30 dBm (+20 to -40dB) the level reading changes from -65 to -5 dB
( -64 to -4 dB) •
6.1.4
FUNCTIONAL TEST OF THE TEST PROBE CONNECTOR [18]
This test is carried out without a test signal at the inputs.
-Select digital mode with pushbutton "DGTL" and absolute level
display 1r1ith pushbutton "ABS" •
-Note the displayed absolute level.
- Connect the power supply cable of the Test Probe TK-11 to socket
[18] and read the indicated level. The digital display is corrected
by +10 dB.
The same result can be achieved if ground potential is connected to
socket [18].
6.2
FUNCTIONAL TESTS OF IMPORTANT MODULES (HARDWARE SELF-TEST)
A functional test of the most important modules (hardware self-test)
can be executed by recalling program number 9003. No external connections are required for this purpose. The internal calibration signal
is the signal source.
Sequence:
Depress the following pushbuttons:
; 1 2? e~?..
"MEM"
"MEM II
'1 o 0 .;)
Vl
9001
"RCL"
9003
01
"RCL
(only A Series)
1 ) Max. tolerable level, external signal of +25 dBm/+16 dB
(AC plus DC components, see also para. 4.3).
6-6
If the test is successful, the message 1----- appears on the frequency
display. The Level Meter can then be switched back from the test progr·arn to the measuring program via 9001 "RCL". In the case of a fault,
a fault number (e.g. 1--003) appears in the frequency display; these
fault numbers are explained in Table 6-2. Repairs should be carried
out only by trained personnel. If it is not possible to repair the defective rrodule, which means that the SPM-16 has to be sent into the
factory for repair, it is recomnended that you also specify the fault
number which occurred.
An RAM/ROM test is carried out automatically by the Level Meter when
power is switched on (see section 3.5). The meanings of the fault numbers for this test are also shown in Table 6-2.
CLASS
0
0------
0--1-L
0--lH0--lHL
0--200
FAULT IN CONTROL SECTION (NOT VIA IEC BUS)
NO FAULT, INDICATION OF TEST EXECUTION
RAM FAULT ON 00 ••• 03
THE ADDRESS IS SHOWN IN THE LEVEL DISPLAY
RAM FAULT ON 04 ••• D7
THE ADDRESS IS SHOWN IN THE LEVEL DISPLAY
RAM FAULT ON 00 ••• 03 AND ON D4 ••• 07
THE ADDRESS IS SHOWN IN THE LEVEL DISPLAY
ROM FAULT
THE ADDRESS IS DISPLAYED IN HEX WITH THE FOLLOWING
CODES:
L FOR A
H FOR 8
P FOR C
A FOR 0
- FOR E
(BLANK) FOR F
Table 6-2
Overview of fault numbers in the SPM-16
6-7
CLASS I: HARDWARE SELF-TEST
INDICATION: 9003
SELF-TEST RUNNING
INDICATION: 1----- SELF-TEST IS COMPLETE AND NO FAULT WAS
DETECTED IN THE LEVEL MEASURING SECTION.
TEST GROUP OOX
FUNCTIONS: GENERAL MODULE TEST
THE TEST SIGNAL IS THE CALIBRATION LEVEL
FAULT MESSAGES:
1
1--001
CALIBRATION LEVEL AT WIDE-BAND DETECTOR TOO LOW
POSSIBLE SOURCES OF FAULT:
CONTROL FREQUENCY NOT CONNECTED; CALIBRATION LEVEL TOO
LOW
PREAMPLIFIER 1 or 2
WIDEBAND DETECTOR
1--002
CALIBRATION LEVEL AT WIDE-BAND DETECTOR TOO HIGH
CALIBRATION LEVEL TOO HIGH; PREAMPLIFIER 1 or 2
WIDEBAND DETECTOR, 10 kHz SIGNAL DERIVED FROM
40 MHz GENERATOR IS MISSING
1--003
LEVEL AT SIGNAL DETECTOR TOO LOW.
MEASUREMENT MODE: WIDEBAND
POSSIBLE SOURCES OF FAULT:
10 kHz BANDPASS FILTER, IF AMPLIFIER
1--004
LEVEL AT ANALOG-DIGITAL CONVERTER (ADC) TOO LOW.
MEASUREMENT MODE: WIDEBAND
POSSIBLE SOURCES OF FAULT:
INACCURATE CALIBRATION LEVEL, PREAMPLIFIER 1 or 2
WIDEBAND DETECTOR; 10 kHz BANDPASS FILTER,
IF AMPLIFIER, DETECTOR, ADC
Table 6-2 Overview of fault numbers in the SPM-16 (continued)
6-8
1--00S
ON ANALOG-DIGITAL l.ONVLfnF.R (Aile) TOO IIIGII
\4 In! 1\/\Nil
f'OSSII\LI SOUI~ClS 01 I 1\lll l: /\~) liNilll{ 1--tlll'l
LEVEL
~1EASUR!Jvlf:NT ~10!1F.:
1--006
LEVEL ON SIGNAL LlLTLCfOI\ ruo LOW
MEASUREMENT MODE: SELECTIVE (400 Hz)
POSSIBLE SOURCES OF FAULT:
220, 180, or 40.01 MHz OSCILLATOR UNLOCKED
MIXER 1, 2, or 3; 40 MHz or 10 kHz BANDPASS FILTER
1--007
LEVEL ON ANALOG-DIGITAL CONVERTER (ADC) TOO LOW
MEASUREMENT MODE: SELECTIVE (400 Hz)
POSSIBLE SOURCES OF FAULT:
220, 180, or 40.01 MHz OSCILLATOR UNLOCKED
MIXER 1. 2, or 3; 40 MHz or 10 kHz BANDPASS FILTER
1--008
LEVEL ON ANALOG-DIGITAL CONVERTER (ADC) TOO HIGH
MEASUREMENT MODE: SELECTIVE (400 Hz)
POSSIBLE SOURCES OF FAULT:
MIXER 1, 2, or 3; 40 MHz or 10 kHz BANDPASS FILTER
TEST GROUP 01X:
FUNCTION: TEST FOR INTOLERABLE DEVIATION FROM FREQUENCY RESPONSE
MEASUREMENT MODE: WIDEBAND
FAULT ANNUNCIATION:
l-Oll
INTOLERABLE DEVIATION FROM FREQUENCY RESPONSE AT
1-012
INTOLERABLE DEVIATION FROM FREQUENCY RESPONSE AT
1-013
INTOLERABLE DEVIATION FROM FREQUENCY RESPONSE AT
1-014
INTOLERABLE DEVIATION FROM FREQUENCY RESPONSE AT
1-015
INTOLERABLE DEVIATION FROM FREQUENCY RESPONSE AT
1-016
INTOLERABLE DEVIATION FROM FREQUENCY RESPONSE AT
POSSIBLE SOURCES OF FAULT:
VARIATION OF CALIBRATION SIGNAL WITH FREQUENCY
PREAMPLIFIER 1 or 2, WIDEBAND DETECTOR
10 kHz
1 MHz
30 MHz
60 MHz
110 MHz
160 MHz
TEST GROUP 02X:
FUNCTION: TEST FOR INTOLERABLE DEVIATi~\ FROM FREQUENCY RESPONSE
MEASUREMENT MODE: SELECTIVE
FAULT ANNUNCIATION:
INTOLERABLE DEVIATION FROM FREQUENCY
INTOLERABLE DEVIATION FROM FREQUENCY
INTOLERABLE DEVIATION FROM FREQUENCY
INTOLERABLE DEVIATION FROM FREQUENCY
INTOLERABLE DEVIATION FROM FREQUENCY
INTOLERABLE DEVIATION FROM FREQUENCY
POSSIBLE SOURCES OF FAULT:
VARIATION OF CALIBRATION SIGNAL WITH
PREAMPLIFIER 1 or 2, MIXER 1
1--021
1--022
1--023
1--024
1--025
1--026
Table 6-2
RESPONSE
RESPONSE
RESPONSE
RESPONSE
RESPONSE
RESPONSE
AT
AT
AT
AT
AT
AT
10 kHz
1 MHz
30 MHz
60 MHz
110 MHz
160 MHz
FREQUENCY
(continued)
6-9
TEST GROUP lOX:
FUNCTION: TEST OF SYNTHESIZER (ADDER)
FAULT ANNUNCIATION:
1--101
FALSE RESULT FROM ADDITION
1--102
ADDER COUNT INCOMPLETE
1--103
ADDER SIGNAL DAC RD1AINS LOW
1--104
ADDER SIGNAL "0,1\C" REMAINS HIGH
1--105
ADDER DOES NOT BEGIN TO ADD
11
I CLASS
2:
11
OPPERATOR ERRORS
I
2--001
FALSE ADDRESS NUMBER
2--002
ROM ADDRESS: "STORE" NOT POSSIBLE
(FIXED FREQUENCY OR SET-UP FROM EPROM)
2--003
ADDRESS CAN BE USED ONLY WITH RECALL
(TO RECALL PRINTER, AND TEST PROGRAMS)
2--004
START AND STOP ADDRESSES ARE IN DIFFERENT RANGES (BOTH
MUST LIE EITHER BETWEEN 0 AND 99 OR BETWEEN 200 AND 299)
2--006
ADDRESS NOT PROGRAMMED
2--101
MEASURING RANGE TOO SENSITIVE
2--102
MEASURING RANGE TOO INSENSITIVE
2--103
WIDE-BAND SECTION OVERDRIVEN (WITH 80 dB SCALE)
2--104
MEASURING RANGE UNSUITABLE FOR "STORE ABS AS REF"
2--201
"STORE ABS AS REF" NOT PERMITTED
(SWEEP OR SEARCH MODE)
CLASS 3:
FAULTS IN THE DIGITAL INTERFACE [40] [41]
3--000
INITIALIZATION REQUEST FROM A PERIPHERAL DEVICE (TO BE
REGARDED AS AN ACKi'IOVJLEDGEMENT AND NOT AS A FAULT: APPEARS
DURING INITIALIZATION OF THE DEVICE)
3--XXX
FAULT AT THE DIGITAL INTERFACE
11
11
IF THE ABOVE FAULTS OCCUR, THE DATA CONNECTION BETWEEN THE
RECEIVER AND THE GENERATOR SHOULD BE EXAMINED.
Table 6-2
6-10
Overview of fault numbers in the SPM-16 (continued)
II
I!
0.3
MAINTENANCE AND MISCELLANEOUS
The Level Meter SPM-16 requires no special maintenance provided it
is handled correctly. The enclosure protects the electronic cirucuits
at all times, even during transport. The use of corresponding Protective Cover SO 5 is recommended in order to protect the controls on the
front panel and the sockets on the rear of the unit against splash water, dust, and mechanical damage. In addition, the SPM-16 can be
carried with the carrying handle of the protective cover.
For major transport under rough conditions, the use of the TRANSPORT
CONTAINER TPK-5 or the Transport Case TPG-65 is recommended (see
section 3. 1. 2 ) •
6.3.1
MECHANICAL CONSTRUCTION
Caution:
Before opening the unit, disconnect the a.c.power plug
from the outlet socket. The unit must always be switched
off before removing or inserting moduler or auxiliary devices.
The case dimensions comply with the DIN Standard 41 494 and the American Standard ASA C 83.9. The unit can therefore be mounted in 19"
racks (see section 3.1.3). The cover, baseplate, and side walls are
made of rugged cast aluminum. For servicing purposes, it is possible
to remove the six Allen head screws (wrench on the rear of the unit),
to take off the equipment cover, and to lift the complete chassis including the front panel and the rear wall from the case.
When doing this, remember that the chassis is connected to the power
supply unit on the right wall of the case via a plug connector. All
modules are access i b1e from the top and the bottom if the hto screws
of the two folding chassis are removed.
When assembling, ensure that the blue flat cable is not trapped
between the chassis and the case. During repairs, ensure that the
upper fol~ing chassis cannot fall, as this could result in damage to
the cables.
Figure 6-2 shows details of the components in the upper folding chassis after removal of the equipment cover. Amongst other things, the
microprocessor (INTEL 8085) and the free positions for the optional
6-11
Interface Bus <rEC 625)
Card ~ Auxiliary devices
Parallel Poll Switch
~p
8085
Address Switch
CPU board
CPU mother board
@
Pushbutton T (21 S 1)
@
Figure 6-2
6-12
Option BN 874/00.01
(EPROM)
Adder circuit ~
Upper side of the upper folding chassis
accessories: IEC- or printer-interface and EPROM (fixed frequencies,
set-ups) with customer-specific programs can be seen in this figure.
The pushbutton T is depressed only after repair in order to bootstrap
the SPM-16 if the buffer battery for the RAM power supplies was disconnected during repair (see section 3.6).
6.3.2
CHANGING OR INSTALLING THE INTERFACE BOARDS
The plug-in modules Printer Interface BN 905/02 (SPM-16, series B or
1ater) or Interface Bus <rEC 625) card BN 853/02 are installed from
the rear· of the unit (see Figure 4-2). Rerrovi ng the tvJo outer screws
provides access to the compartment and the board can be inserted or
changed (component side on the top). The interface board is then held
in position with the two screw.
. 6.3.3
INSTALLING THE EPROM BN 874/00.01
The EPROM BN 874/00.01 can be installed in the SPM-16 at any time. As
the customer-specified data are stored in aMOS memory module (EPROM),
the board must be installed as described below, owing to the sensitivity of the circuit to static charges.
Generally, whenever working with MOS components, all tools, work benches and technicians should have the same reference potential. For
this reason, the MOS module should be installed as follows:
1. Switch off the Level Meter.
2. Rerrove the six Allen head screws (vlrench on the rear of the unit)
and take off the equipment cover.
3. Touch the SPM-16 (reference potential) with one hand, rerr~ve
the MOS module from its packing material with the other hand (holding it at the ends), and insert it in the position shown in Figure
6-2. The module is oriented correctly if the inscription is in the
same direction as on the other EPROMs.
4. Fit the equipment cover, screw it down, and switch on the Level
Meter.
6-13
6.3.4
UNIVERSAL CONVERSION SYSTEM VERSACON@ 9
The coaxial input, the inputs and outputs for control in standard
frequencies, and the IF output at the Level Meter are equipped with
the universal conversion system Versacon ® 9 made by Wandel & Goltermann (Figure 6-3). This has the advantage that it permits rapid
conversion to one of the connection sockets shown below without soldering. The required socket adaptor is screwed into the fixed universal socket, using the mounting wrench (Order No. W1).
11
.~
'
Versacon®9
Lemo
.
fl
11
.
.;·i·
pi~
.
',,
BNC
1.6/5.6
2.5/6
1.6/10
558A
470(
Western Electric
Figure 6-3
6.3.5
Basic socket Versacon® 9 with some of the available
Versacon ® 9 adaptors
RECHARGEABLE BATTERIES FOR DATA RETENTION
The power supply unit on the right side wall contains rechargeable
batteries: 3 Ni-Cd cells 501 RS, type Mignon IEC R 6. These ensure,
if the mains voltage is interrupted temporarily or switched off, that
the last settings which were entered and all stored data are retained.
The batteries are trickle-charged whenever the Level Meter is switched
on.
11
11
If the Level Meter was switched off for a longer period, it is recommended that it be left on for approximately 8 hours in order to fully
recharge the batteries. The batteries are stored in the battery compartment N on the rear of the unit (see Figure 4-2). To replace the
cells, remove the two philips head screws, permitting the battery
holder to be pulled out.
When fitting new cells, ensure that their polarity is correct, as
shown on the cover.
6-14
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