Keysight Technologies N9330B, User Manual

Page: 37 / 107

Making Measurements
Measuring Distance to Fault (DTF)
31
Measuring Distance to Fault (DTF)
For this measurement, an internally generated signal
emits from the RF OUT port of the tester and is
transmitted to the cable and antenna system (DUT). The
tester receives and processes the signal power reflected
from faults and imperfections.
In performing a DTF measurement, the tester uses
frequency domain reflectometry. The transmitted and
reflected signals contain information about the distance
to the faults. This information is used to determine the
physical distance to the faults. The tester displays the
physical distance to the probable faults, corrected for
cable loss and the velocity propagation factor of the
cable.
Perform a DTF measurement
To make a DTF-return loss measurement over a
frequency range of 50 to 400 MHz, perform the following
steps:
1 Press
[FREQ/DIST] > {Start} > 50 > [ENTER]
to set the
start frequency to 50 MHz.
2 Press
{Stop} > 400 > [ENTER]
to set the stop frequency
to 400 MHz.
3 Press the
[MODE]
hardkey to select a measurement
mode. Rotate the front-panel knob to highlight and
select the DTF-Return loss, and press
[ENTER]
to
confirm your selection.
4 Press
[CAL]
to bring up the calibration process
guidance. Follow the instructions to perform a
calibration. For more information about calibration,
refer to "Calibrate the N9330B before making
measurements" on page 25 .
5 Remove the calibrator and connect the cable under
test (DUT) to the RF OUT connector on the top panel
of the tester. The DTF measurement starts and the
results are displayed on the screen. A peak in the
horizontal trace indicates a defective location. 