Running Individual Tests 4
The TDR Test
The TDR Test
The TDR (Time Domain Reflectometry) test helps you locate impedance anomalies on a cable by reporting the locations of signal reflections caused by the anomalies.
The test locates anomalies caused by problems such as shorts, opens, poor connections, and mismatches in cable types. You can view the location and size of the anomalies in a list or plot format.
The reflection values displayed are adjusted to compensate for cable attenuation. The values represent the approximate size of the reflections as they appear at the anomalies.
How to Terminate the Cable
You can run the TDR test on twisted pair cable with or without a remote unit, and on coaxial cable with or without a terminator. Table
Cable Type and
Termination
Table
Listed Results Show the Following: Plotted Results Show the Following:
Twisted pair with no termination
Displays the message
No Remote Detected. Results show the two largest reflections greater than or equal to 15%. The largest reflection probably comes from the end of the cable, but is not identified as the end.
All reflections are shown.
Twisted pair with remote
Coaxial cable with no terminator
Coaxial Cable with terminator
Two largest reflections greater than or equal to 15%. Largest reflection is identified as the end of the cable.
Two largest reflections greater than or equal to 10%. The largest reflection comes from the end of the cable, but is not identified as the end.
No Reflection reported for a good cable. On a faulty cable, the test reports the two largest reflections, but does not identify end of cable.
All reflections are shown.
All reflections are shown. The largest reflection comes from the end of the cable.
All reflections are shown. The plot will not show a reflection from the terminated end.
