Locating Faults Using The Tdr - Viavi OneExpert DSL User Manual

Locating faults using the TDR

The Time Domain Reflectometer (TDR) feature helps locate cable faults. The TDR identifies
bridged taps, wet sections, load coils, shorts, opens, and splices on the span.
1. Connect the Tip (A), Ring (B), and Ground (Earth) leads to the line under test.
2. From the Copper menu, press the TDR button. The TDR graph appears.
3. To change the TDR mode, press the Mode system key, and then select Standard TDR,
In Home TDR (does not include Pulse Width), SmartGain TDR, OneCheck TDR or
Crosstalk TDR.
4. If running In Home TDR, twist the
cables for more consistent impedance.
5. To change the cable type, select the
Options system key, and then select
Cable Type.
6. To add a DC pulse in order to see changes in the graph, select the Options system key,
and then select Stress. The spike or dip will shift when the pulse is applied.
A warning appears during the stress pulse to indicate higher voltage is present.
NOTE:
The TDR must be running for Stress Mode to be available. It is
grayed out when the TDR is stopped.
7. Using the Peak Hold mode, the OneExpert DSL can display minimum, maximum, and
current TDR traces over a test period. This feature is useful for analyzing faults that
occur intermittently. To enable Peak Hold mode, select the Options system key and
then check the Peak Hold checkbox.
8. To adjust the Gain or Pulse Width, either drag the line across the bar or press the + or -
buttons to adjust it.
Gain is used to identify small or distant faults. Using the + or -
vertical axis and enhance the reflection of faults. Do not apply excessive gain. This
makes a normal condition appear as a fault.
Pulse Width only appears when Pulse Width is selected on the Options pop-up menu
(from the Options system key).
9. To help identify small or distant faults, use the up or down arrow keys to gain the
vertical axis and enhance the reflection of faults. Do not apply excessive gain. This
makes a normal condition appear as a fault.
May 2020
OneExpert DSL User's Guide
22052280, Rev. 016
Chapter 4 Copper Testing
buttons to gain the
95