User`s guide

Agilent E6432A Microwave Synthesizer User’s Guide 4-45
HPE6432_GenerateAndLoadExtFreqTable
ViStatus HPE6432_GenerateAndLoadExtFreqTable (ViSession
instrumentHandle, ViReal64 startDetFreqRangeHz, ViReal64
stopDetFreqRangeHz, ViReal64 stepFreqHz);
Purpose
This function is used to perform an external modulation-gain
calibration on an external leveling loop configuration over a frequency
range specified by the start and stop frequency values at points
specified by the step value. When completed, the calibration results are
loaded into the synthesizer’s FLASH memory.
NOTE This calibration could take up to 15 minutes to complete and can not be
aborted once it has started; it must run to completion
NOTE For best results when calibrating an external leveling loop
configuration, both the External Detector Linearization and External
Modulator Gain Calibration must be run. When running these
calibrations, order matters; the External Modulator Gain Calibration
must be run only after an External Detector Linearization is run.
NOTE Running these calibrations a second time may yield a minor
improvement in accuracy; the accuracy improvement is less than
0.25 dB. Running these calibrations any additional times provides no
further accuracy improvement.
An external modulation-gain calibration is used to adjust the external
leveling loop configuration and provide adjustment values that enhance
the performance when switching between open and closed loop.
Assuming the factory preset values remain present, this calibration has
no effect when the external leveling loop configuration is closed, it only
affects the output power when the loop is opened.
This calibration is required (or desirable) if the operator plans to use an
external leveling loop configuration and operate the synthesizer in open
loop mode. This calibration is good for frequencies, as defined by the
user based on the start, stop, and step size. The smaller the step size,
the more accurate the adjustment values are, but enhanced accuracy is
at the cost of increased time for the calibration process. There is only
one adjustment made for the full power range at any given frequency, so
they are not optimal for frequency-power pairs. To obtain even better
performance for frequency-power pairs, the power-search function can
be used. The power-search function returns a correction factor that is
sent to the synthesizer when tuning to a frequency and power which
has optimum open-loop performance.