Model 4402B
Model 4402B
Ultra-Pure Sinewave Oscillator
1Hz to 110kHz
Typical Distortion of 0.0005%
Serial No. ____________
Operating Manual
15 Jonathan Drive, Unit 4, Brockton, MA 02301 U.S.A.
Tel: (508) 580-1660; Fax: (508) 583-8989
www.krohn-hite.com; info@krohn-hite.com
Copyright © 2003 Krohn-Hite Corporation. All rights reserved. Contents of this publication may not be reproduced
in any form without the written permission of Krohn-Hite Corporation. Printed in USA - 4/03.
Table of Contents
TABLE OF CONTENTS
SECTION 1 .
1.1 . . .
1.2 . . .
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.6
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GENERAL DESCRIPTION
I NTRODUCTION . . . . . . .
S P E C I F I C AT I O N S . . . . . .
FREQUENCY . . . . . . . . .
MAIN OUTPUTS . . . . . . .
FIXED OUTPUT . . . . . . .
QUADRATURE OUTPUT . .
GE N E R A L . . . . . . . . . . .
OP T I O N S . . . . . . . . . . . .
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SECTION 2 .
2.1 . . .
2.2 . . .
2.2.1
2.3 . . .
2.3.1
2.3.2
2. 3. 3
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OPERATION . . . . . . . . . . . . . . . . . . . . . 2-1
POWE R RE QUI RE M E NT S . . . . . . . . . . . . . . . 2 - 1
OPE RAT I NG CONTROLS AND CONNECTORS . 2 -2
RE A R PA N E L . . . . . . . . . . . . . . . . . . . . . . . 2 - 2
OPE RAT I ON . . . . . . . . . . . . . . . . . . . . . . . . 2 - 3
FREQUENCY CONTROL . . . . . . . . . . . . . . . . 2 - 3
AM P L I T U D E C O N T R O L . . . . . . . . . . . . . . . . 2 - 3
FL O AT I N G G R O U N D . . . . . . . . . . . . . . . . . . 2 - 3
SECTION 3 .
3.1 . . .
3.2 . . .
3.3 . . .
3.3.1
3.3.2
3.3.3
3.3.4
3.3.5
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INCOMING ACCEPTANCE . . . . .
I NTRODUCTION . . . . . . . . . . . . .
L I ST OF E QUI P M E NT RE QUI RE D .
PROCEDURE . . . . . . . . . . . . . . .
DC L E V E L A D J U S T M E N T S . . . . . .
F REQUENCY ACCURACY . . . . . .
M A I N O U T P U T AM P L I T U D E . . . . .
AM P L I T U D E F L AT N E S S . . . . . . . .
O U T P U T DI S TORT I O N . . . . . . . . .
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. . . 1-1
. . . . 1-1
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. . . . 1-2
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. . . . 1-3
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. . . 3-1
. . . . 3-1
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. . . . 3-2
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. . . . 3-2
. . . . 3-3
. . . . 3-3
SECTION 4 . . . CIRCUIT DESCRIPTION . . . . . . . . . . . . . 4-1
4 . 1 . . . . . T HE ORY OF OP E RAT I ON . . . . . . . . . . . . . . . 4 - 1
4 . 2 . . . . . AVC OPE RAT I ON . . . . . . . . . . . . . . . . . . . . 4 - 2
Table of Contents - i
Model 4402B Ultra-Pure Sinewave Oscillator
FIGURES
Section 1
F i g u r e 1 . 1 . Ty p i c a l O u t p u t D i s t o r t i o n . . . . . . . . . . . . . . . 1 - 3
Section 2
Fi g u r e 2 . 1 . Op e r a t i n g Co n t r o l s a n d Co n n e c t o r s . . . . . . . . . 2 - 1
Section 3
F i g u r e 3 . 1 . Te s t S e t - U p fo r M e a s u r i n g Amp l i t u d e F l a t n e s s . . 3 - 2
Section 4
F i g u r e 4 . 1 . M o d e l 4 4 0 2 B S i mp l i f i e d Bl o c k D i a g r a m . . . . . . 4 - 1
F i g u r e 4 . 2 . Si mp l i fi e d AVC Di a g r a m . . . . . . . . . . . . . . . . 4 - 2
Section 5
F i g u r e 5 . 1 A . . Tr o u b l e s h o o t i n g F l o w c h a r t . . . . . . . . . . . . . 5 - 3
F i g u r e 5 . 1 B . . Tr o u b l e s h o o t i n g F l o w c h a r t . . . . . . . . . . . . . 5 - 4
ii - Table of Contents
Model 4402B Ultra-Pure Sinewave Oscillator
Model 4402B
Sinewave Oscillator
iii - Table of Contents
Model 4402B Ultra-Pure Sinewave Oscillator
This page intentionally left blank.
iv - Table of Contents
General Description - Section 1
SECTION 1
GENERAL DESCRIPTION
1.1 INTRODUCTION
The Model 4402B is an ultra-pure sinewave, stable amplitude oscillator designed to meet the needs of today’s high precision 16 to 18 bit A/D converter testing, and audio test and measurement technology.
Covering the frequency range from 1Hz to 110kHz, with precise 3 digit frequency tuning, the 4402B produces a virtually “distortion-free” (<0.0005%) sinewave for measuring A/D converter accuracy, audio
preamplifier and power amplifier harmonic distortion. With its exceptionally flat response (0.02dB), the
4402B eliminates the need to constantly monitor voltage levels, during frequency response tests.
The 4402B provides a 7Vrms sinewave output, (balanced output, 14Vrms end-to-end), 3.5Vrms into 50
ohms, and has no loss in performance when loaded with a linear 50 ohm load.
A 3-position, push-button attenuator calibrated in 20dB steps, along with the a 30dB vernier, provides a
total dynamic range of 90dB.
Simultaneous fixed and quadrature (90°) outputs are provided. Each output is 7Vrms with 600 ohm
source impedance.
The 4402B is the perfect addition to your present test and/or precision measurement set-up.
1.2 SPECIFICATIONS
The following specifications apply to the Main, Quadrature and Fixed Outputs, except where noted.
1.2.1 FREQUENCY
Range: 1Hz to 110kHz.
Accuracy: ±0.5% of frequency setting.
Control: 2 digits of frequency, calibrated in 1Hz and 0.1Hz steps, with a calibrated vernier providing
continuous coverage between the 0.1Hz steps, plus a 5 decade push-button multiplier with overlapping
ranges.
Stability:
Vs. Time: 0.01% in 1 hour or less.
Vs. Temperature: 0.05%/°C.
Vs. Line: <0.001% for a 10% change in line voltage.
General Description - 1-1
Model 4402B Ultra-Pure Sinewave Oscillator
1.2.2 MAIN OUTPUTS
Maximum Amplitude: 7V rms open circuit (balanced output, 14V rms end-to-end); 3.5Vrms; +48dBm
into 50 ohm load (balanced output, 7V rms end-to-end).
Impedance: Constant 50 ohms.
Maximum Current: 75mA rms.
Minimum Amplitude: <0.2mV.
Amplitude Flatness: ±0.02dB, 1Hz to 110kHz.
Amplitude Stability:
Vs. Time: 0.01% in 1 hour or less.
Vs. Temperature: 0.05%/°C.
Vs. Line: <0.001% for a 10% change in line voltage.
Amplitude Control: A 4-position push-button attenuator calibrated in 20dB steps from 0dB to –60dB,
Accuracy, ±0.25dB/20dB step; Volts rms control with greater than 30dB of coverage calibrated in volts.
Accuracy: ±20% of setting.
Main Output Distortion:
Frequency
1Hz to 10kHz
10kHz to 20kHz
20kHz to 50kHz
50kHz to 110kHz
Distortion %
<0.0005
<0.0018
<0.0056
<0.01
Distortion (dB)
–106
–95
–85
–80
Hum and Noise: Greater than 110dB below signal (10Hz to 20kHz detector bandwidth).
1.2.3 FIXED OUTPUT
Amplitude: 7V rms open circuit; 3.5V rms (+13dBm) into 600 ohm load.
Impedance: Constant 600 ohms.
Amplitude Flatness, Amplitude Stability and Distortion: Same as Main Output.
Phase Accuracy (180°, top BNC, Main Output): 1Hz to 10kHz, ±0.4°; 10kHz to 110kHz, ±5°.
1.2.4 QUADRATURE OUTPUT
Amplitude: 7V rms open circuit; 3.5V rms (+13dBm) into 600 ohm load.
Impedance: Constant 600 ohms.
Amplitude Flatness: ±2dB, 1Hz to 110kHz.
Amplitude Stability: Same as Main Output.
Phase Accuracy (–90°): 1Hz to 1kHz, ±0.2°; 1kHz to 10kHz, ±1°; 10kHz to 110kHz, ±10°.
1-2 - General Description
General Description - Section 1
1.2.5 GENERAL
Ambient Temperature Range: 0°C to 50°C.
Power Requirements: Switch selectable, 90-132 or 180-264 volts, single phase, 50-60Hz, 18 watts.
Floating Ground: Rear panel switch floats circuitry ground from chassis ground up to 100V.
Dimensions: 31 2“ (8.9cm) high, 9" (23cm) wide, 81 2” (21.6cm) deep.
Weights: 5 lbs (2.3kg) net; 7 lbs (3.2kg) shipping.
Accessories: 3-terminal line cord and operating manual.
1.2.6 OPTIONS
Rack Mounting Kit: Part No. RK-39 permits the installation of the Model 4402B into a standard
19"rack spacing.
Optional Rack Mount Kit RK-39
Extended 1 Year Warranty: Part No. EW4402B.
Figure 1.1
Typical Output Distortion
General Description - 1-3
Model 4402B Ultra-Pure Sinewave Oscillator
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1-4 - General Description
Operation - Section - 2
SECTION 2
OPERATION
2.1 POWER REQUIREMENTS
The Model 4402B is powered from a single phase, 50Hz to 60Hz ac line voltage of either 90V to 132V or
180V to 264V. A selector switch on the rear panel selects the desired voltage range.
The fuse receptacle on the rear panel contains 1/4A slow-blow fuse for 120V operation and a 1/8A fuse
for 240V operation.
Figure 2.1 Operating Controls and Connectors
Operation - 2-1
Model 4402B Ultra-Pure Sinewave Oscillator
CAUTION!
The cover of this instrument should not be removed when
the instrument is connected to an ac line power source,
because of the potentially dangerous voltages that exist
within the unit.
2.2
1.
OPERATING CONTROLS AND CONNECTORS
(see Figure 2.1 at the end of this section)
Power: On-off rocker switch with power-on indicator.
2.
Frequency Hz: 2 rotary decade switches calibrated in 1Hz steps (1-10) and 0.1Hz steps (0-9), plus a
calibrated vernier providing continuous coverage between the 0.1Hz steps. A 5-band push-button
multiplier multiplies the frequency setting in decade steps from x1 to x10k.
3.
Amplitude: 4-position push-button attenuator calibrated in 20dB steps from 0dB to 60dB, plus a
single-turn VOLTS RMS control with greater than 30dB of coverage. Dynamic output range 0dB
to –90dB.
4.
Main Output: two BNC connectors. Maximum output, 7Vrms open circuit (14Vrms end-to-end,
balanced) and 75mA rms loaded with a linear 50 ohm load. Output Impedance, 50 ohms, ±1%.
5.
Fixed 7Vrms: BNC connector. Fixed at 7Vrms open circuit. Output is inverted by 180° on the top
Main Output BNC; and is in phase with the bottom Main Output BNC (see Figure 2-1). Output impedance 600 ohms, ±1%.
6.
Quad 7Vrms: BNC connector. Fixed at 7Vrms open circuit. Quadrature (90°) with respect to top
Main Output BNC. Output impedance, 600 ohms, ±1%.
2.2.1 REAR PANEL
7.
Main Output DC Level (bottom BNC): Screwdriver control for periodic adjustment of the Main
Output DC Level.
8.
Main Output DC Level (top BNC): Screwdriver control for periodic adjustment of the Main Output DC Level.
9.
Circuit Ground: Slide switch. In the FLOATING mode, the signal ground becomes disconnected
from chassis ground.
10. AC Power Receptacle: Standard, 3-prong connector complies with European I.E.C. standard. A
detachable, 3-wire line cord is included.
11. Line: Slide switch. Use 120V position for ac line voltages between 90V to 132V; use 240V position
for ac line voltages between 180V to 264 V.
12. Fuse Receptacle: Use a 1/4A, slow-blow fuse for 120V operation and 1/8A, slow-blow fuse for
240V operation.
2-2 - Operation
Operation - Section - 2
2.3
OPERATION
2.3.1 FREQUENCY CONTROL
The frequency of the 4402B is controlled by 2 rotary decade switches, a 3rd digit vernier and a 5-decade
multiplier. The decade switches are calibrated in 1Hz steps from 1 to 10 and 0.1Hz steps from 0 to 9. The
3rd digit vernier is calibrated from 0->9, and provides additional resolution between the 0.1Hz steps.
The 5-band push-button multiplier is calibrated in decade steps from x1 to x10k.
Multiplier
x1
x10
x100
x1k
x10k
Frequency Range
1.00Hz to 11Hz
10.0Hz to 110Hz
100Hz to 1.1kHz
1.00kHz to 11kHz
10.0kHz to 110kHz
2.3.2 AMPLITUDE CONTROL
The Main Output control is controlled by a 4-position push-button attenuator; and a single turn variable control. The attenuator is calibrated in 20dB steps from 0dB to 60dB. The VOLTS RMS control
is calibrated in volts and provides an additional 30dB coverage on each attenuator position.
Attenuator
0dB
20dB
40dB
60dB
Volts RMS Range
(Main Output)
220mV to 7V
22mV to 700mV
2mV to 70mV
220µV to 7mV
To optimize the resolution of the adjustment, use the lower of the two attenuator settings (e.g. if the application requires a 500mV rms signal, use the 20dB setting rather than the 0dB setting).
The Quad (90°) and Fixed (180° out of phase from top Main Output BNC) outputs are fixed at 7Vrms.
The output impedance of each of these outputs is 600 ohms.
2.3.3 FLOATING GROUND
The CIRCUIT GROUND switch on the rear panel allows the oscillator to “float” or isolate the oscillator
circuit or signal ground from the chassis or earth ground. Maximum allowable DC isolation is 100V.
Operation - 2-3
Model 4402B Ultra-Pure Sinewave Oscillator
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2-4 - Operation
Incoming Acceptance - Section 3
SECTION 3
INCOMING ACCEPTANCE
3.1 INTRODUCTION
The following procedure should be used to verify the oscillator is operating within specifications, both
for incoming inspection and routine servicing. Tests should be made with the cover in place, and the procedure given below should be followed in sequence. Familiarize yourself with the set-up and operating
procedures outlined in Section 2, Operation.
CAUTION!
The cover of the unit should not be removed when the instrument is connected to an ac power source, because of
potentially dangerous voltages that exist within the unit.
3.2 LIST OF EQUIPMENT REQUIRED
1. Oscilloscope: bandwidth of at least 1MHz, vertical sensitivity 10mV/cm, ac/dc coupled.
2.
DC Voltmeter: 0V to ±15V.
3.
AC Voltmeter: Frequency range <10Hz to >110kHz, to measure between 0V and >7Vrms, better
than 3% accuracy.
4.
RMS Voltmeter for Measuring Amplitude Flatness: Able to measure ac voltage variations of
<0.02dB (0.23%) from 10Hz to 110kHz.
or
High Frequency Thermal Converter: Fluke Model A55 and either a DC Differential Voltmeter
(Fluke Model 895A), or a DC Null Detector (Fluke Model 845A) with a stable, DC reference supply.
5.
Spectrum Analyzer: Able to measure harmonic components below 0.0005% (–106dB).
6.
Frequency/Period Counter: Accuracy better than 0.5%, 1Hz to 110kHz.
Incoming Acceptance - 3-1
Model 4402B Ultra-Pure Sinewave Oscillator
3.3 PROCEDURE
Allow the Model 4402B to warm-up for at least 30 minutes, then set the controls on the front and rear
panels to the following positions:
Frequency Hz: 1kHz (1-0-0 x1k).
Amplitude: 0dB, Volts RMS set for maximum clockwise (CW).
Circuit Ground: Chassis.
3.3.1 DC LEVEL ADJUSTMENTS
Connect the DVM to the Main Output and adjust the rear panel screwdriver control marked “MAIN
OUTPUT DC LEVEL” (adjusts the dc level for the top Main Output BNC connector) for a reading of
0V. Repeat the same for the bottom Main Output marked on the rear panel “MAIN OUTPUT DC
LEVEL”.
3.3.2 FREQUENCY ACCURACY
Connect the frequency counter to either Main Output. Verify that the frequency accuracy is within 0.5%
of the FREQUENCY Hz setting between 1Hz and 110kHz.
3.3.3 MAIN OUTPUT AMPLITUDE
Set the 4402B frequency to 1kHz (1-0-0 X1k). Connect the ACVM to the Main Output; with the VOLTS
RMS control set to maximum CW, the Main Output should be ³7Vrms. Rotate the VOLTS RMS control
to minimum (counter clockwise, CCW), the Main Output should be <220mV. Turn the VOLTS RMS
clockwise to obtain a reading of 7Vrms. Connect a 50ohm resistor ±1% across the top BNC of the Main
Output; the voltage should drop to 3.5Vrms. Repeat the same for the bottom BNC at the Main Output.
Remove the 50W terminator.
To check the attenuator accuracy, adjust the VOLTS RMS control for an ACVM reading of 7Vrms. Verify that the attenuation accuracy is within ±0.25dB (±2.9%) per 20dB step.
Connect the ACVM to the FIXED OUTPUT. The ACVM should read ³7Vrms. Connect a 600 ohm load
(±1%) across the FIXED OUTPUT; the amplitude should drop ½ the value. Repeat the same for the
QUAD OUTPUT.
Figure 3.1 Test Set-Up for Measuring Amplitude Flatness
3-2 - Incoming Acceptance
Incoming Acceptance - Section 3
3.3.4 AMPLITUDE FLATNESS (see set-up on next page)
Amplitude flatness is defined as the maximum deviation from constant amplitude expressed in dB or %
over a specified frequency range. Since few ac voltmeters are capable of accurately measuring voltage
deviations <0.02dB (0.23%) up to 100kHz, the use of a high frequency thermal converter, and either a
differential dc voltmeter or dc null meter with a calibrated or stable dc supply, is recommended (see Figure 3.1).
Minimize the capacitance in the meter leads to avoid loading effects at the higher frequencies.
Set the frequency of the Model 4402B to a reference frequency of 1kHz and adjust the voltmeter or null
meter for a 0dB/0% deviation. Tune the oscillator frequency from 10Hz to 110kHz. The Main Output
should remain constant within ±0.02dB (±0.23%) over the entire frequency range.
Repeat this procedure for both Main Outputs and the Fixed Output. Repeat for the Quad Output, tolerance, ±2dB (±2.5%).
3.3.5 OUTPUT DISTORTION
The use of a spectrum or wave analyzer (HP, B&K, Marconi, etc.) and a pre-filter is recommended for
distortion measurements below 0.001%. The pre-filter consists of a passive “twin-tee” or notch filter,
and is used to attenuate the fundamental frequency in order to increase the sensitivity of the spectrum or
wave analyzer.
Component Values:
R = 7.96k, ±1%
Center Frequency (Hz)
100
1k
10k
Capacitance (µF)*
0.1
0.01
0.001
* Capacitance values are ±1% tolerance
Incoming Acceptance - 3-3
Model 4402B Ultra-Pure Sinewave Oscillator
The diagram below shows the test set-up for measuring the output distortion of the 4402B.
To measure distortion, proceed as follows:
1. Set the controls on the analyzer to the following initial positions:
ADAPTIVE SWEEP
DISPLAY
FREQUENCY
AMPLITUDE MODE
AMPLITUDE REFERENCE LEVEL
INPUT SENSITIVITY
RESOLUTION BANDWIDTH
FREQUENCY SPAN/DIV
SWEEP TIME/DIV
SWEEP MODE
Off
Clear Write
1kHz
Log dB/Div
0 (Zero)
+20dB (10V)
100Hz
0.5Hz
1Sec
Repetitive
2.
Set switch S1 to the “INPUT” position. Adjust the 4402B frequency to correspond to the
“twin-tee” null frequency.
3.
Adjust the INPUT SENSITIVITY vernier on the analyzer to obtain a 0dB reference at the fundamental frequency.
4.
Switch S1 to the “OUTPUT” position. Adjust the frequency of the 4402B to null the fundamental
frequency. It may be necessary to make fine adjustments to the “twin-tee” component values to obtain sufficient null of the fundamental.
5.
Increase the INPUT SENSITIVITY in dB steps until the harmonic components are visible.
The dB level of each harmonic component is the sum of the dB below the 0dB reference level on the display, plus the change in the INPUT SENSITIVITY level, in dB.
To compensate for loss through the “twin-tee” filter, add +9dB to the second harmonic component and
+5dB to the 3rd harmonic component.
For example, if the second harmonic is –128dB: –128dB +9dB = –119dB.
The total harmonic distortion may then be calculated as follows:
T . H . D.( dB ) = 20 log log -1
Since: log -1 ( x ) =
2 nd
10
+ log -1
3 rd
10
+...log -1
nth
10
1
= 10 (x)
log( x )
T . H . D.( dB) = 10 log(10
dB 2 nd
10
+ 10
T . H . D.( dB) = 10 log å (10 10 )
dB 3 rd
10
= 10
dB 4 th
10
+...10
dBnth
10
)
dBn
3-4 - Incoming Acceptance
dBn = sum of all harmonics
Incoming Acceptance - Section 3
Example: 2nd harmonic = -40dB
3rd harmonic = -46dB
4th harmonic = -50dB
-40
-46
-50
T . H . D. = 10 log(10 10 + 10 10 + 10 10 )
= 10 log(10 -4 + 10 -4. 6 + 10 -5 )
= 10 log(100m + 25m _10m )
= 10 log(135m )
= 10 ´ -3.87
= -38.7dB
-38. 7
20
% = (10
% = 116
.
) ´ 100
Incoming Acceptance - 3-5
Model 4402B Ultra-Pure Sinewave Oscillator
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3-6 - Incoming Acceptance
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