| 摘要 |
<p>PURPOSE:To accurately detect an accident point and to investigate the cause of malfunction by providing a storage means for storing signals of respective terminal ends of a cable to the measurement units of both ends of cables. CONSTITUTION:A counting circuit 23 counts the time from the generation of a pulse by a pulse generating circuit 22 with the output of a level decision circuit 21 to the output of the level decision circuit 21 with a received pulse P7, and wave memory circuits 27 and 37 are provided on the output sides of abnormality decision circuits 24 and 34 of a measurement circuit 2a which detects abnormality by an abnormality determining circuit 24 according to the counted time and a measurement unit 3a of similar constitution. Then when abnormality is detected, the contents of the wave memory circuits 27 and 37 are displayed and compared with the counting results of the counting circuits 23 and 33 to judge whether or not an accident actually occurs and whether or not it is caused by a noise.</p> |
