Power Meter - HP 8901B Operation And Calibration Manual

Model
8901B
Adjustments
Adjustment 20
POWER METER
0
Service Sheet 1
Description
The frequency of the 220 Hz multivibrator is adjusted for a maximum power reading of a nominal
input signal. This occurs when the phase shift through the ac amplifier chain of the power meter is
zero.
T w o
linearity adjustments are then made on the two highest power ranges using a power meter
range calibrator.
Equipment
Extender Cable
.............................................................
HP 08901-60179
Range Calibrator..
...............................................................
H P 11683A
Procedure
1. Connect the power meter output of the range calibrator
to
the Modulation Analyzer's SENSOR
2. On the range calibrator, set the function to calibrate, polarity to normal, and range to 1 mW.
3. On the Modulation Analyzer, press
RF
POWER. Adjust A53R40 (FREQ) for a maximum reading
4. On the Modulation Analyzer, press
S
(Shift) AUDIO FREQ. Set AUDIO INPUT
to
read external.
5. On the Modulation Analyzer, connect the MODULATION OUTPUT/AUDIO INPUT to A53TP4
6. Remove the cable from A53TP4.
7. On the range Calibrator, set the function
to
standby.
8. On the Modulation Analyzer, press
RF
POWER. Press ZERO and wait for the instrument
to
zero.
9. On the range calibrator, set the function to calibrate.
input.
on the Modulation Analyzer's display (approximately 1 mW).
(MLTVIB).
The Modulation Analyzer's display should read between 204 and 236 Hz.
10. On the Modulation Analyzer, press CALIBFMIX then press the blue key then press SAVE CAL
(again, the CALIBRATE key). This normalizes the power reading
to
1 mW. (The CALIBRATE
key light should be on.)
11. On the Modulation Analyzer, key in 10.4 SPCL
to
set the power meter to range 4.
12. Set the range calibrator range
to
10 mW. The Modulation Analyzer's display should read between
9.99 and 10.01 mW. If it does not, perform the following steps.
a. Switch the Modulation Analyzer off and extend the A53 RF Power Assembly.
b. Connect the extendercable to the RF Power Assembly. Connect the range calibrator
to
the
c. Switch the Modulation Analyzer back on. Repeat steps 7 to 12.
d. Adjust A53R13 (RNG 4) for a Modulation Analyzer display of 10.00 mW.
sensor connector on the extender cable.
13. On the Modulation Analyzer, key in 10.5 SPCL to set the power meter to range 5.
Adjustment 20 5-33