Identification system for transmission wires carrying digital signals - having constant pulse repetition frequency and phase, which periodically changes impedance

摘要

The system alters the reactance at a point in the wire being considered during the transmission of the digital signals in the signal path before the place under investigation. The digital signals at the place of investigation are examined for the occurrence of phase modulation of the appropriate period. In the case of double wires, the impedance of both wires is altered in opposition. The impedance is changed periodically by connecting a reactance to the wire concerned at a frequency chosen by taking into account the signal-to-noise ratio at the receiver. A phase-demodulator is used to detect phase modulation and has a bandpass filter at its output.