MM0474
(b) Range and Tracking.
1.
Position controls of H-P 8402B as indicated below:
Function switch to current off.
Mount resistance to correspond to mount in use.
Current and vernier fully CCW.
2. Connect power meter terminals of power meter calibration
terminals of H-P 431C.
3.
Set mount res switch of 431C to correspond to mount in use.
4.
Set H-P 8402B and H-P 431C Range switches to some reading.
5.
Place function switch of H-P 8402B to calibrate.
6.
H-P 431C should indicate full scale.
7. When 10 mW range is reached, continue adjusting range on
8402B to 8, 6, 4, and 2 mW positions. H-P 431C meter should track at these
readings. If not, meter movement is defective.
4.
POWER MEASUREMENT USING H-P 431C POWER METER WITH THE H-P 8402B CALIBRATOR
(DC SUBSTITUTION).
a. Measurement principles.
(1) Apply the RF power to the thermistor mount and note the power meter
reading.
(2) Remove the RF power and substitute a DC current from an external DC
power source to precisely duplicate the reading obtained.
(3) Calculate the power from the substituted DC current and thermistor
operating resistance.
b. Procedure.
(1) Equipment connection, see Figure 2.
(2) Technique.
(a) Operate signal source in CW mode (leveled).
(b) Set RANGE switch on power meter to 10 mW and adjust level set
attenuator for full-scale reading on power meter. Record corresponding reading
on digital voltmeter.
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