Loss Of Power Meter Calibration Data - HP 8753E User Manual

Loss of Power Meter Calibration Data

The power meter calibration data will be lost by committing any of the following actions:
Turning power off. 'Inming off the instrument efases the power meter calibration table.
power meter calibration is on, the calibration data will be lost. However, calibration data is
retained if you change the sweep type while power meter calibration is off.
Chaugiug frequency. Power meter calibration data will also be lost if the frequency is
changed in log or list mode, but it is retained in linear sweep mode.
Pressing m. Presetting the instrument will erase power meter calibration data. If the
instrument state has been saved in a register using the k-j key, you may recall the
instrument state and the data will be restored. Saving the instrument state will not protect
the data if the instrument is turned off.
Interpolation in Power Meter Calibration
If the frequency is changed in linear sweep, or the start/stop power is changed in power sweep,
then the calibration data is interpolated for the new range.
If calibration power is changed in any of the sweep types, the values in the power setting array
are increased or decreased to reflect the new power level. Some accuracy is lost when this
occurs.
Power Meter Calibration Modes of Operation
You can set the analyzer to update the correction table at each point for sweep (as in a
power level at every frequency point each time it sweeps You can also have more than one
sample/correction iteration at each frequency point. (See the ~~~~~:~~~~~~ softkey
description in Chapter 9.)
While using the continuous sample mode, the power meter must remain connected as shown
in Figure 6-55. A power splitter or directional coupler samples the actual power going to the
test device and is measured by the power meter. The power meter measurement provides the
information necessary to update the correction table via HP-IB.
Continuous correction slows the sweep speed considerably, especially when low power levels
are being measured by the power meter. It may take up to 10 seconds per point if the power
level is less than -20 dBm. For faster operation, you can use the sample-and-sweep mode. If
you use a directional coupler, youmust enter the attenuation of the coupled arm with respect
to the through arm using the '~~~~~~~~ softkey.
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Application and Operation Concepts