Internal Modulation Frequency Test - Wavetek 3000 Instruction Manual

PERFORMANCE TESTS
SPECIFICATION
METHOD
Amplitude & Fre-
quency Modulation
4 .10 INTERNAL MODULATION FREQUENCY TEST
2 . Connect the Signal Generator RF out connector to the
50 ohm RF input of the modulation meter .
3 . Set the modulation meter to read FM deviation at 520
MHz .
Set the meter range switch to 3, the RF input attenuation
to 20 dB, the IF bandwidth to t400 kHz, the meter response
to fast and the filter bandwidth to 50 Hz-15 kHz .
4 . Measure the average level
of the FM deviation on the
modulation meter and disregard occasional peaks .
The resi-
dual FM should be <200 Hz . Read the residual FM on the panel
meter with the function switch set to +FM and then -FM posi
tions .
Record the greater of the two readings in Hz on line
26 of the PTR .
As many other frequencies may be tested as desired .
Internal
400 Hz and 1 kHz +5I
A frequency counter is used to measure modulation frequency
at the rear-panel modulation test pointof the Signal Gener-
ator .
Since the internal 400 Hz and 1 kHz oscillators are
used for both the AM and FM modes, this test will suffice
for both modes .
EQUIPMENT
Frequency Counter HP5300B/5303B
PROCEDURE
1 . Set the Signal Generator controls as follows
FREQUENCY selector
N/A (not applicable to this test)
MODULATION MODE
N/A
MODULATION FREQ
400 Hz
MODULATION FM/AM
Mid-range
OUTPUT VERNIER N/A
OUTPUT step attenuator N/A
2 .
Connect the low frequency input of the frequency counter
to the rear-panel
MODULATION T .P . of the Signal Generator .
NOTE : Provide a ground connection between
the Signal Gen-
erator and the counter .
3 .
The counter should read between 380 and 420 Hz . Record
the counter reading on line 27 of the PTR.