Fault location device for buried electric cables - has auxiliary pickup producing tone-burst enhancement of detector signals

摘要

The electric cable location apparatus comprises an acoustic pickup (3) connected to an amplifier (5), mixer amplifier (6) and headphones (7). The microphone is placed over the run of an underground cable (1). An auxiliary search coil (8) which picks up the cable fault noise spikes, is connected to a peack voltage detector (10) whose output switches on an audio oscillator for about one tent of a second. The oscillator tone bursts of around 5 kHz frequency are mixed with the signals from the microphone to produce an overall audio response characteristic which distinguishes cable fault pulses from the general background noise.