HP 8901B

Operation
Model 8901B
the calibrator output, the instrument will not zero properly.) The controller uses the zeroing digital-
to-analog converter
(DAC) in the power meter to output a dc voltage to cancel any dc offset that may
be present
at the power sensor. The zeroing process persists until the reading is zero, which may take
several seconds to complete.
MODULATION ANALYZER
1
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TO OTHER TUNED
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MEASUREMENT CIRCUITS
;ENSOR MODULE
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INPUT
RF ELEMENT CHOPPER DETECTOR DISPLAY
RF POWER
SENSING
INPUI
RF Power Block Diagram
-7
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MODULATION ANALYZER
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IOENTIFIER
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RF
INPUT
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El&@ CALIBRATION
POWER REF
OSCILLATOR
Simplified Block Diagram of RF Power Calibration
3-76 RF Power