Advertisement
Adjustments
Model 8902A
Resistance
(k0)
26.1
Adjustment 9-FM
Calibrator
HP Part Number
0698-31 59
REFERENCE
Service Sheet 29.
DESCRIPTION
The FM calibrator
is
set to CW and its frequency is adjusted while being monitored by the internal
counter. The calibrator is then set
to
modulate, and the symmetry is adjusted
as
the demodulated
signal
is measured with the peak+ and peak- detectors. The computed peak deviation is checked and
if out of limits, a resistor is changed
to
bring the deviation within the proper limits.
NOTE
T h i s
calibration adjustment
is
not critical. Built-in safeguards minimize
the possibility
of
erroneous calibration. If conditions exist that are out
of
calibration, the Measuring Receiver displays an error message.
PROCEDURE
1.
Connect CALIBRATION AM/FM OUTPUT to INPUT. (The CALIBRATION AMFM OUT-
PUT can be connected either to a sensor module or directly to the Measuring Receiver's
INPUT.)
2. Key 12.1 SPCL and 46.3 SPCL.
This
sets the
FM.
calibrator to CW and connects the internal
counter to measure the calibrator's frequency.
3. Using a non-metalic tool, adjust A51C20 (FREQ) for a display between 1009OOO and 1011OOO.
If the frequency cannot be adjusted high enough, change A51R32 to
11
kn (HP part number
4. Key in 12.2 SPCL then 5.1 SPCL. This
seta
the instrument to display the demodulated FM from
0757-0443).
the calibrator and
sets
the peak detector time constant to slow.
28.7
31.6
34.8
38.3
0698-3449
0698-5446
0757-01 23
0698-31 61
U
E
I
Y Y
Y
5-16
rev.15OCT88
Advertisement
Chapters
