Wavetek 3000 - FM Bandwidth Test

4 .15 FM BANDWIDTH TEST
SPECIFICATION
EQUIPMENT
PERFORMANCE
TESTS
3 . Read the frequency counter and record the reading to
8 places on line 36 of the PTR .
4 . Adjust the Signal Generator MODULATION FM/AM control to
0 kHz deviationon the FM scale .
5 .
Read
the
frequency counter and record the reading
to
8
places on line 37 of the PTR .
6 .

Subtract the readingobtained in step 5 from the reading
obtained in step 3 .

Thedifferencebetween thetwo readings
should be between 4 .749 and 5 .251 kHz .

Record the difference
in kHz on line 38 of the PTR .
7 .

Set the Signal Generator
MODULATIONMODE
to
FMx100
and
adjust the MODULATION
FM/AM
control to 5 kHz deviation
on theFM scale .
8 . Read the frequency counter and record the reading to 6
places on line 39 of the PTR .
9 .
Adjust the Signal Generator MODULATIONFM/AM control to
0 kHz deviation on the
FM
scale .
10 . Read the frequencycounter
and record the reading to 6
places on line 40 of the
PTR .
11 .

Subtract the reading obtained instep
10 from the read
ing obtained in step
8 .

The difference
between
the
two
readings should be between 464 .9 and 535 .1 kHz . Record the
difference in kHz on line 41 of the PTR .
Modulation

External,
DC to >25 kHz (1
dB bandwidth)
Frequency
METHOD

The
measurement is
made
with
a modulationmeter and a func-
tion generator .

The function generatorsupplies an external
sine
wave to
frequency modulate
the Signal Generator .

The
system is

calibrated at 0 dB on the modulation
meter dB
scale (approximately 320 kHz deviation) . The external mod-
ulation frequency is increased from 1 kHz to 25 kHz and
FM
bandwidth is measured as the change in dB level from the
calibration level .
ModulationMeter

RadiometerAFM2
Function Generator Wavetek 130
Oscilloscope

Tektronix
D10/5A18N/5B10N
4- 23