| 摘要 |
PURPOSE:To prevent the erroneous display due to the reflection by a building or other foreign noise and to facilitate the searching of an accident point, by mounting a pair of counters, a pair of counter resetting means, a pair of signal holding means and a signal processing means. CONSTITUTION:Counters 20A, 20B count a signal showing the direction of an accident point so as to be classified by the direction of a distribution line and output signals when the number of counts are a predetermined value or more. Counter resetting means 21A, 21B rest one counter when the other counter starts counting. Signal holding means 22A, 22B input the outputs of the counters of hold the same themselves and output signals showing the direction of the accident point of the distribution line. Self-holding reset means 23A, 23B, 31B, 31A reset one signal holding means when the other starts self-holding. A signal processing means 25 outputs a signal confirming whether the direction of the accident point shown by the output signals of the means 22A, 22B is correct. By this method, the correct direction of the accident point can be discriminated from the displays of signal display devices 13A-13C.
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