HP 8901B Operation And Calibration Manual page 195

Operation
Model 8901B
Power Measurements Alter Some Instrument States
The instrument exits the automatic tuning mode when the
RF
Power function
is
selected. The RF,
LO, and
IF
sections are inactive since power is being measured at the external sensor.
Reference Cal Factor Not Affected by Changing the Cal Factor Mode
The SAVE CAL key, used in conjunction with RF Power Calibration, scales subsequent RF power
measurements to the 1 mW RF Power Reference and saves the Scaling Factor in non-volatile memory.
Changing the calibration factor mode does not change the reference calibration factor in use; for
example, if the Modulation Analyzer is calibrated from the manual cal factor mode and then the
Automatic Cal Factor mode is selected, the instrument will continue to use the manually-entered
reference calibration factor until another SAVE CAL operation is initiated from the Automatic
Calibration Factor mode.
Manual Cal Factors
Manual Cal Factors are not frequency selective; that is, as frequency is changed, the instrument will
continue to use the calibration factor entered last. To obtain accurate measurements when using Manual
Cal Factors, a new calibration factor should be entered each time the frequency is changed.
The Manual Calibration Factor is not retained in the Modulation Analyzer's non-volatile memory and
therefore, must be re-entered after AUTOMATIC OPERATION or INSTR PRESET is selected.
3-80
RF Power