HP 8753D, User Manual, Page: 363 / 678

Loss of P ower Meter Calibration Data
The power meter calibration data will be lost by committing any of the following actions:
Turning power o. Turning o the instrument erases the power meter calibration table .
Changing sweep type . If the sweep type is changed (linear , log, list, CW , power) while
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 o.
Changing frequency . P ower 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 4 PRESET 5 . Presetting the instrument will erase power meter calibration data. If the
instrument state has been saved in a register using the 4 SA VE/RECALL 5 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 o.
Interpolation in P ower 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 reect the new power level. Some accuracy is lost when this
occurs .
P ower Meter Calibration Modes of Operation
Continuous Sample Mode (Each Sweep)
Y ou can set the analyzer to update the correction table at each point for sweep (as in a
leveling application), using the
N NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
EACH SWEEP softkey . In this mode , the analyzer checks the
power level at every frequency point each time it sweeps . Y ou can also have more than one
sample/correction iteration at each frequency point. (See the
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
NUMBER OF READINGS softkey
description in Chapter 9.)
While using the continuous sample mode , the power meter must remain connected as shown
in Figure 6-54. 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 020 dBm. F or faster operation, you can use the sample-and-sweep mode . If
you use a directional coupler , you must enter the attenuation of the coupled arm with respect
to the through arm using the
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
POWER LOSS softkey .
6-96 Application and Operation Concepts