3M 965AMS manual Tdr, TDREvent Recognition

3M™ Dynatel™ Advanced Modular System 965AMS Measurement Functions

TDR

Use the Time Domain Reflectometer (TDR) function to map the high-frequency impedance of the cable along its length. The display shows opens, load coils, splits, wet sections, splices, gauge changes, heavy shorts and any other physical deviation from a perfect cable. Each of these events have their own unique signature. A user-controlled vertical cursor is used to measure the distance to an event.

TDR>Event Recognition

“Events” are the “dips” and “peaks” seen on the screen caused by faults or changes in the pair.

“Peak” Events

1.Launch Pulse: The first peak on the screen is the “launch pulse” which occurs where the transition from the tester to the test leads occurs.

2.Open: A clean or partial open will show up as a peak on the screen. The “cleaner” the open, the taller the peak. A complete open will be the tallest peak (other than the launch pulse).You can not see events past a complete open.

3.Load Coil: A load coil looks very similar to an open. If you think there is a load coil on the pair, use the Load Coil function (in the POTS test) to verify its presence. You can not see events past a traditional load coil.

117