| 摘要 |
PURPOSE:To make it possible to discriminate the number and polarity of a core, by using the preparatory specific numbered core wire in a cable as a control circuit to output reference signal from one terminal of the cable while sending out a collation signal to a core to be collated from the other terminal of the cable to compare both signals in the other terminal side. CONSTITUTION:The output of an oscillator 1 is guided to the connection terminal 2 of a specific numbered core C-2 through a transformer T1 while a modulation signal outputted from the side of a receiving part R through a cable C is inputted to a differential amplifier 4. The output of the amplifier 4 passes a zone filter 5 to take out only a modulation signal component while a signal component is taken out by a demodulator 6 and a digital display device 7 for displaying the polarity and number of the core is driven by said signal. The output of a channel change-over device 10 is inputted to a synchronous detector 15 through a differential amplifier 11. The terminal of the specific number core C-2 is applied to the detector 15 through an amplifier 12, BPF13 and a phase shifter 14 and connected to a threshold value judging part 16. As mentioned above, core collating work can be performed while the polarity and number of the core is visually confirmed by a colimation signal transmission side 5.
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