MM0474
state, respectively. On this basis, the power meter can be used to indicate
the presence of the 10 kHz audio bias.
(3) With the 431C Power Meter RANGE switch set to NULL, a stable meter
indication greater than zero indicates a 10 kHz oscillation and a meter reading
of zero indicates no oscillation.
The operating resistance of the detection
thermistor element is somewhere between the percentage deviations indicated by
the two switch settings that correspond to a no-oscillation and an oscillation
state. The presence of an audio bias signal in the power meter can also be
determined at the calibrator OUTPUT (10 kHz) BNC jack. This jack connects to
the audio bias lead at the thermistor mount end of the thermistor mount cable.
7.
POWER METER CALIBRATOR MODEL 8477A FOR THE MODEL 432A POWER METER
THE MODEL 8477A POWER METER CALIBRATOR IS USED TO CALIBRATE IT.
a. Description. The 8477A Calibrator is a specialized instrument designed
to verify full-scale calibration of the model 432 Power Meter. Essentially a
precision DC voltage source, the calibrator connects to the power meter's
bridge circuits to simulate the effect of power dissipation in a thermistor
mount.
b. Specifications.
(1) Calibration Function: Output voltages corresponding to meter reading
of: 0.01, 0.03, 0.1, 0.3, 1, 2, 3, and 10 mW.
(2) Calibration Uncertainty: 0.5% on 0.01 mW range and 0.2% on 0.1 to
10 mW ranges.
c. Operation, function and purpose are similar to the model 8402B Power
Meter Calibrator.
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