
Model 8640B
TM 9-4935-601-14-7&P
PERFORMANCE TESTS
4-41. INCIDENTAL AM TEST
SPECIFICATION:
Incidental AM: (at 400 Hz and 1 kHz rates)
<0.5% AM for FM up to 1/8 max. allowable deviation.
<1% AM for FM at max. allowable deviation.
DESCRIPTION:
An audio signal is used to amplitude modulate the Signal Generator. The resulting modulated RF is detected and used
to calibrate an oscilloscope. The generator is then frequency modulated and any incidental AM is measured with the
oscilloscope.
Figure 4-27. Incidental AM Test Setup
EQUIPMENT:
Crystal Detector ..................................................................................... HP 423A
15 kHz Low Pass Filter (LPF) .................................................. CIR-Q-TEL 7 Pole
40 dB Amplifier ...................................................................................... HP 465A
Oscilloscope.....................................................................HP 180A/1801A/1820C
50 Ohm Load ..................................................................................... HP 11593A
Nine-Inch Cable ................................................................................. HP 10502A
Adapter .............................................................................................. HP 10110A
0.001 µF Capacitor ....................................................................... HP 0160-0153
10 k
Ω
Resistor . ....................................................................... . HP 0757-0442
4-68
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