Adjustments Model
8901B
Adjustment
7
15
KHZ
AND
>20
KHZ
LOW-PASS
FILTER
GAIN
Service
Sheet
12
Description
A
signal generator
is
amplitude modulated
at
a
1
kHz rate. The signal
is
demodulated
by
the Modulation
Analyzer with no low-pass, audio filtering. Using the ratio feature, the demodulated signal
is
referenced
to
100%.
The low-pass filtering
is
then set
to
>20
kHz and
15
kHz,
then the filter gain of each
is
adjusted for
a
reading
of
100%.
Equipment
Signal Generator.
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HP 8640B
Procedure
1,
Set the signal generator
to
11
MHz at
0
dBm with
30%
AM at
a
1
kHz
rate.
Connect
its
FW
output to the Modulation
Analyzer’s
INPUT. (The signal source can be connected either
to
a
sensor module or directly
to
the Modulation Analyzer’s INPUT.)
2. On the Modulation Analyzer, press the blue key then press INSTR PRESET (the AUTOMATIC
OPERATION key)
to
preset the instrument. Press
AM.
Set DETECTOR
to
AVG.
3.
Set
RATIO
on (with LOG/LIN set for
a
linear display). The display should show between
99.95
and
100.05%
REL.
4. Set LP FILTER
to
>20 kHz. Adjust A2R44
(
>20 kHz LPF GAIN) for
a
display of
99.95
to
100.05%
REL.
5.
Set LP FILTER
to
15
kHz. Adjust A2R40
(15
kHz
LPP GAIN) for
a
display of
99.95
to
100.05%
REL.
5-14
Adjustment
7
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