| 摘要 |
A digital time domain reflectometer includes a pulse generator for generating a test pulse to a cable under test and comparator circuits for determining whether a reflected voltage pulse exceeds user-selected bias values thus indicating an impedance mismatch. Signal processing means which may include a computer and associated logic circuits set the bias values, trigger the pulse generator and record the time at which the reflected voltage pulse was observed. The digital time domain reflectometer may operate in a search mode in which it examines the entire cable for faults of increasingly less severity or may be used to determine the impedance signature of a cable by examining all impedance faults along its entire length.
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