Wavetek 3000 - FM Distortion Test

4 .16 FM DISTORTION TEST
SPECIFICATION
METHOD
Distortion

<4% (3 to
10 kHz deviation), -<2% (10 to 500 kHz deviation)
at a
frequency of 1 kHz
EQUIPMENT
ModulationMeter

RadiometerAFM2
DistortionAnalyzerHP334A
8 . Record the larger of the two dB changesobtained in
steps 6 and 7
on line
42 of
the
PTR .
The measurement is madewith a modulationmeter and a dis-
tortion analyzer, whichmeasures the distortion of the de-
modulatedFM from the modulation meter . Distortionbelow 3
kHz
deviationincreases because of residualFM noise . The
distortion at 3 kHz deviation is measured in an environment
where the noise level <60 dB relative to 2x10 -4 ubar .
PROCEDURE

1 .
Set the Signal Generator controls as follows :
FREQUENCY
selector

520 .000
MHz
MODULATIONMODE

FMxl
MODULATION FREQ

1 kHz
MODULATIONFM/AM

3 kHz
OUTPUTVERNIER

Fully Clockwise
OUTPUT step attenuator

+10 dBm
2 . Connect the equipment as shown in Figure 4-7 .
Figure 4-7 . FM
Distortion Setup
PERFORMANCE TESTS
3 .

Setthe modulationmeter to readFMdeviation at 520 MHz .
Set the RF input attenuation to 20 dB, the IF bandwidth to
t400 kHz, the meterresponse to fast, the function switch to
4- 25
Model
3000
Signal
Generator
Modulation
Meter
Distortion
An alyzer
Input
RF
AF O
RF Out
IrIput
Output
O