HP 8901B Operation And Calibration Manual page 414

Model
8901B
Adjustments
Adjustment 14
AM CALIBRATOR
0
Service Sheet 30
Description
The Modulation Analyzer is set to read
%AM as
computed from internal measurements. The AM
depth is adjusted for
33.33%.
The AM is then demodulated and the symmetry is adjusted as the signal
is measured with the peak+ and peak- detectors.
NOTE
This
calibration adjustment
is
not critical. Built-in safeguards minimize
the possibility
of
erroneous calibration.
If
conditions exist that are out
of
calibration, the Modulation Analyzer displays an error message.
Procedure
1. Connect CALIBRATION A M P M OUTPUT
to INPUT. (The CALIBRATION AMPM OUT-
PUT
can be connected either
to a
sensor module or directly
to
the Modulation Analyzer's
INPUT.)
2.
Key in
13.0
SPCL. This sets the instrument to display the
AM
computed from internal
measurements.
3.
Adjust A50R45
("A"
LVL) for a display of
33.330
to
33.336%.
4. Key in 49.5 SPCL. This Connects the internal voltmeter
to
measure the output le&l from the
AM
calibrator. The display should read between 1.8 and
2.2.
5. Key in
13.2
SPCL then 5.1 SPCL. This sets the instrument to display the demodulated AM from
the calibrator and sets the peak detector time constant to s l o w .
6.
Alternately set the DETECTOR to PEAK+ and PEAK- and note the display for each setting.
Adjust A50R39 (SYMM) until the readings are the same for both detectors within
*0.015%.
Adjustment 14
5-23