Keysight N9923A, User Manual, Page: 93 / 276

Keysight N9923-90001 User’s Guide
93
DTF (Distance to Fault) Measurements
DTF Measurement Settings
—
Bandpass Mode
(Default setting) The frequency range of a DTF
measurement is set manually. Use Bandpass mode when the DUT
contains a diplexer or other filtering device which does not pass
some frequencies.
Typically, you will set the frequency range of the measurement to the passband
of the filter. However, you may also want to test the ability of the filter to reject
unwanted frequencies. In this case, set the frequency range to include those
frequencies which the filter may not be adequately rejecting.
When the DTF frequencies are set manually, they may not be the optimum
frequencies for measuring the distance to fault. The distance may no longer be
alias-free. Learn more about alias-free range on page 98 .
How to manually set Frequencies in Bandpass Mode
— Press
Freq/Dist
— Then
Min Start Freq and type the start frequency to use for the DTF
measurement.
— Then
Max Stop Freq
and type the stop frequency to use for the DTF
measurement.
— OR
— Press
More
— Then
Max Freq Span
and type the frequency range to use for the DTF
measurement.
— Then
Center Frequency
and type the center frequency of the range to use
for the DTF measurement.
These settings specify the minimum and maximum frequencies to be used for
the DTF measurement. These exact frequencies may not be used, but a
narrower frequency range may be used that will still pass through the
bandpass filter.
To see the frequencies that are used in the DTF measurement, press
Meas
Setup 4
then
Settings
then
Next Page
. The calculated Start and Stop
frequencies determine the exact frequency range being used.
Coupled Frequency
When both a DTF and non-DTF measurements are present, this setting allows
you to have different frequency ranges for each measurement. Learn more in
“Coupled Frequency” on page 84
.