CIRCUIT FOR GENERATING CONTROL SIGNAL INDICATIVE OF TRANSMISSION LINE RESISTANCE

摘要

A circuit for varying the amplification afforded to a-c signals transmitted through a transmission line in accordance with the a-c losses of that transmission line. Gain control circuitry is provided which varies the magnitude of amplifying voltages and currents inserted into the transmission line in accordance with the a-c losses of that transmission line. The gain control circuitry is comprised of a line resistance sensor which establishes a control signal which is a function of the a-c losses of the transmission line. The line resistance sensor establishes the control signal by establishing one signal which varies in accordance with the voltage across the transmission line and another signal which varies in accordance with the current through the transmission line and then dividing the signals one into the other to thereby establish the control signal. This control signal is applied to the remainder of the gain control circuitry to vary the magnitude of voltages and currents inserted into the transmission line in accordance with that control signal. As a result, the gain control circuitry automatically adjusts the gain of a repeater in accordance with each transmission line connected thereto.