| 摘要 |
PURPOSE:To discriminate a selected cable in a hot-line state by providing a mechanism for double-sending a frequency synchronized with a fundamental frequency and applied with FS modulation at every half cycle, to the fundamental frequency, and a mechanism for transmitting a signal to a cable shielding layer. CONSTITUTION:Frequencies of f1 and f2, and a frequency of f3 are generated by a frequency divider 2 and a frequency divicer 3, respectively, by using a transmitter 1 as an original oscillator, and the frequencies of f1 and f2 are converted to an FS signal by an FS modulating part 4, and frequencies of f1 and f2 are generated when a waveform of f3 is positive, and when it is negative, respectively. Subsequently, the frequency of f3 is shaped in waveform by a phase shifting circuit 9, a synchronizing circuit 12 and a comparator 11, and inputted to the respective switching circuits 6, 10 together with the FS signal. Thereafter, it is outputted by the frequency of f1 and f2 when a half cycle of the frequency of f3 is positive and when it is negative, respectively, amplified, and thereafter, transmitted to a cable shielding layer through a clamp CT15. In such way, a selected cable can be discriminated easily.
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