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Performance Tests
Model 8902A
Audio
Synthesizer
Frequency
(Hz)
50 000
100
000
50
20
16. Set the audio synthesizer to 10 kHz at
+5 dBm. Connect its output
to the audio input of the
AM/FM test source. (See Figure 4-2.)
Fine
adjust the level for
a
Measuring Receiver display of
100 kHz times the calibration factor of step 5. (For example, if the calibration factor of step 5
is 100.4%, set the level for a display of 100.4 kHz.)
FM Limits
(kHz)
Lower
Actual
Upper
98.9
-
101.1
94.9
-
105.1
98.9
-
101.1
94.9
-
105.1
NOTE
Flatness
of
the airdio synthesizer is critical for this test.
I f
the airdio
synthesizer
has Itwling capability, swirch
it
on.
17. Set the audio synthesizer to the frequencies in the following table. For each setting, the Mea-
suring Receiver's display should read between the limits indicated in the table.
18. On the Measuring Receiver, set HP FILTER to 50 Hz and LP FILTER to 3 kHz.
19. Set the audio synthesizer frequency to 1 kHz. Set the level for a Measuring Receiver display of
20. On the Measuring Receiver, press AM. Momentarily disconnect the audio input t o the AM/FM
50 kHz peak deviation.
test source and note the residual AM displayed on the Measuring Receiver.
Residual AM:
90
21. Reconnect the audio input of the AM/FM test source. Note the AM displayed on the Measuring
Receiver. The displayed AM minus one-half the residual AM noted in step 20 should be 0.2%
or less.
FM Rejection at 1 kHz Rate;
50
kHz Peak Deviation:
0.2%
FM Distortion, Accuracy, and Rejection-455
kHz IF
22. Connect the FM+32 output of the AM/FM test source to the Measuring Receiver's INPUT.
23.
On the Measuring Receiver, key in
3.1 SPCL to set the IF to 455 kHz. Press FM.
24. Set the audio synthesizer level for a Measuring Receiver display of 5 kHz peak deviation.
25. On the Measuring Receiver, press AM. Momentarily disconnect the audio input to the AM/FM
(See Figure 4-2.)
test source and note the residual AM displayed on the Measuring Receiver.
Residual AM:
0 1 0
26. Reconnect the audio input of the AM/FM test source. Note the AM displayed on the Measuring
Receiver. The displayed AM minus one-half the residual AM noted in step 25 should be
0.2%
or less.
FM Rejection at
1
kHz Rate; 5 kHz Peak Deviation:
0.2%
27. On the Measuring Receiver, press FM. Set all
HP
FILTERS to off and LP FlLTER to >20 kHz.
4-12
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