| 摘要 |
PURPOSE:To prevent malfunctioning due to a distribution constant of a cable to be tested, by judging the results of the testing according to an output of an exclusive OR circuit at a time when a specified time has passed after the starting point of a pulse signal. CONSTITUTION:An oscillator 1 outputs a square wave to an output 2 when a CE terminal is at a H level and a counter 3 outputs counts to Q1-Q4 as binary code as obtained from the counting started at the time of rising in response to the output 2 provided to an input terminal 4. A decoder 5 produces outputs sequentially at any of output terminals 6-13 as the binary codes outputted to the Q2-Q4 of the counter 3 are applied to input terminals E-G. Here, when routes 14, 18 and 16 operate normally without disconnection, the output of the terminal 6 is applied to exclusive OR elements 19 uniformly and hence, the elements 19 output no signal on account of the characteristic thereof. But when there is any disconnection in the routes 14, 18 and 16, the output 6 is applied to only one side of the elements 19 and the elements 19 produces a non-coincidence signal. Thus, the non-coincidence signal appears in the line 20 through outputs of a element block 17.
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