HP 8901B

Model 8901B
Performance Tests
Characteristic
FREQUENCY MODULATION
(cont’d)
Residual FM
AMPLITUDE MODULATION
FM Rejection(2)
Performance Limits
<8 Hz rms at 1300 MHz
decreasing linearly with
frequency to <1 Hz rms
for 100 MHz and below
<0.2% AM
<0.2% AM
Conditions
50 Hz to 3 kHz bandwidth
250 kHz to 10 MHz carrier:
e5 kHz peak deviation;
400 and 1000 Hz rates;
50 Hz to 3 kHz bandwidth
<50 kHz peak deviation:
400 Hz and 1 kHz rates;
50 Hz to 3 kHz bandwidth
10 to 1300 MHz carrier;
(2) Peak residuals must be accounted for in peak readings. (Refer to Residual Noise Effects in Detailed
Operating lnsfrucfions in Section 3.)
Description
FM is measured with a very low-noise oscillator at the Modulation Analyzer’s input. The resulting
measured FM
is the residual FM of the Modulation Analyzer’s internal local oscillator. FM accuracy is
measured with the internal FM Calibrator, which produces approximately 34 kHz peak deviation at a
10 kHz rate. A source, which can produce wide-band, linear FM, is modulated at various FM rates and
deviations to measure distortion, flatness, and incidental AM. A special AM/FM
test source is required
for these tests
to assure that the FM source has adequate bandwidth, low distortion, low residual FM,
and low incidental AM.
Equipment
AMfFM Test Source ............................................................. HP 11715A
Audio Analyzer
................................................................... HP 8903B
Audio Synthesizer.
................................................................ HP 3336C
CAL
HP 89016
MODULATION ANALYZER
0
AUDIO SYNTHESIZER
OUTPUT
(Steps 1.30)
MODULATION
OUTPUT/
OUTPUT
AUDIO ANALYZER
-AUDIO INPUT
z:::; 000000
0000 0
:;;;; 0
0 0 000000 0 0000 0
(Step 15) INPUT
DO
0
I BRAT I ON INPUT
AWFY
OUTPUT
LW RESIDUAL OUTPUT
(Step
I
Finre 4-2. FM Performance Test Setup
Performance Test 2 4-9