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Adjustments
~-
~
HP 8902A
HP 11715A
MEASURINQ RECEIVER
AMIFM TEST SOURCE
0
0
-
OUTPUT
0
0
I
AUDIO
SYNTHESIZER
FM
OUTPUT
0 0 0 0 0 0
0000
0
'
0
0
0
0 0
0
? K T
; ; E ;
0
INPUT
0
0
P
0 0
0000P0 0
0000
0
~
Adjustment 11-FM
Flatness
Model 890244
Reference
Service Sheet
1 1.
Description
The AM/FM test source is frequency modulated at a
1
kHz rate
with 400
kHz peak deviation. The
demodulated FM
is
used
as
a reference. The modulation rate is increased to 150 kHz and the
FM
flatness is adjusted to bring the display back to the reference. The AM/FM test source is required to
assure that the FM source has adequate bandwidth.
Equipment
AM/FM Test Source
............................................................
HP
11715A
Audio Synthesizer.
...............................................................
HP
3336C
Procedure
1. Connect the equipment as shown in Figure 5-4 using a short cable, approximately
0.3
meters
(1 foot), to connect the audio synthesizer. (The AM/FM test source can be connected either
to a sensor module o r directly to the Measuring Receiver's
INPUT.)
2. With the leveling
on,
set the audio synthesizer to
1
kHz
at +5 dBm. On the AM/FM test source, set the test
mode to FM.
3. On the Measuring Receiver, press the blue key then
press INSTR PRESET (the AUTOMATIC OPERA-
TION key) to preset the instrument.
4. Tune the AM/FM test source's carrier frequency to ap-
proximately 400 MHz.
5.
On the Measuring Receiver, press MHz to center its tun-
ing. Press FM. Set DETECTOR to AVG. Adjust the au-
dio synthesizer level for a display of approximately 280
kHz average deviation. Set RATIO on (with LOG/LIN
set f o r a linear display).
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