HP 8901B Operation And Calibration Manual page 100

3-2
Calibration
Disable
Enable
Display
Calibration
The HP 8901B meets its specified AM and FM measurement accuracy
without needing any additional calibration other than the recommended
procedure performed annually to re-calibrate the entire instrument.
The following calibration procedure allows you to further enhance
the accuracy of your AM and FM measurements, however.
16.0 SPCL 17.0 SPCL
16.1 SPCL 17.1 SPCL
16.2 SPCL 17.2 SPCL
AM and FM Calibration
By making comparative measurements against a known modulation
level (provided by the AM/FM CALIBRATION output port),
the instrument creates a calibration factor that can be used to
minimize measurement error. Once the calibration factor has been
created, you have control over when it is used by the instrument.
(There is not a calibration procedure for the @M measurement.)
The following chart lists the special function codes for enabling, disabling,
or displaying the calibration factor; After you have enabled the calibration
factor, the HP 89018 will automatically apply it to its AM or
FM measurements.
AM
FM
Calibration
I
I
I
Note To ensure the highest possible measurement accuracy, allow the
HP
8901B t o warm up a t least thirty minutes before performing
the calibration procedure. Also, to ensure that the measurement
circuitry is fully settled, allow the
HP
8901B t o update the
calibration factor a t least three times before completing the
calibration procedure. (The calibration factor is updated
approximately every
17
seconds while the Calibrator is on.)