TB 9-6625-2059-35
NOTE
If required, use dc coupling on frequency counter.
(4) Repeat technique of (3) above for MODULATION FREQ Hz switch settings
listed in table 5. Frequency counter will indicate within limits specified.
Test instrument
Frequency counter indications (Hz)
MODULATION FREQ Hz switch
settings
Min
Max
01111.1
1110.9889
1111.2111
02222.2
2221.9778
2222.4222
03333.3
3332.9667
3333.6333
04444.4
4443.9556
4444.8444
05555.5
5554.9445
5556.0555
06666.6
6665.9334
6667.2666
07777.7
7776.9223
7778.4777
08888.8
8887.9112
8889.6888
09999.9
9998.9001
10000.8999
10000.0
9999
10001
20000.0
19998
20002
(5) Set VAR control to OFF position.
(6) Set 1 kHz control to midrange. If frequency counter does not indicate between
980 and 1020 Hz, perform b (2) below.
(7) Adjust decade resistor to 150 Ω and connect across TI INT MOD OUT with
multimeter.
(8) Adjust 1 kHz control fully cw. Multimeter will indicate at least 2.5 V ac.
(9) Set MODULATION FREQ Hz switches to 01000.0 and turn 1 kHz control
fully ccw to OFF.
(10) Turn VAR control fully cw. Multimeter will indicate at least 2.5 V ac.
(11) Connect audio analyzer to INT MOD OUT. Measure distortion at 1 kHz. Audio
analyzer will indicate 0.7 percent distortion or less.
(12) Set VAR control fully ccw to OFF and 1 kHz control fully cw. Measure
distortion at 1 kHz. Audio analyzer will indicate 2 percent distortion or less.
(13) Set 1 kHz control fully ccw to OFF and VAR control fully cw.
(14) Set MODULATION FREQ Hz switches to 09999.9. Measure distortion at
9,999.9 Hz. Audio analyzer will indicate 0.7 percent distortion or less.
(15) Set MODULATION FREQ Hz switches to 00100.0. Measure distortion at 100 Hz.
Audio analyzer will indicate 0.7 percent distortion or less.
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