Fault location on PCM transmission line - involves short-circuiting of line and pulse propagation times are measured and differences formed

摘要

The line has a number of repeaters which can be short-circuited. This system ensures that the line can be divided in a series of loops which can be tested by pulses in order to locate the fault. The propagation time of the signal in the preceding loop is measured and stored and the stored value is subtracted from the propagation time in the next loop. The difference in signal values displayed is a measure for the difference of distances.