Abstract: 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. 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 circuit automatically adjusts the gain of a repeater in accordance with each transmission line connected thereto.

Abstract: A circuit for identifying which one of two parties has initiated a toll call. Circuitry connected to the subscriber drop of one party, e.g., the tip party of a two-party telephone line, generates a ground mark during the toll ticketing condition when that tip party has initiated a toll call. Loop current sensing circuitry senses the loop current flowing in the subscriber drop to the tip party. Voltage sensing circuitry senses the potential, with respect to ground, on each conductor of the telephone line. Switching circuitry applies a groundmark to the telephone line when loop current flow to the tip party has been interrupted and negative potential is applied to the tip conductor. Circuitry is also provided which prevents the application of a ground mark when a ringing voltage is applied to the line.

Abstract: A circuit for varying the amplification afforded to a-c signals transmitted through a transmission line in accordance with the length of that transmission line. Circuitry is provided which establishes a control signal which is a function of the a-c losses of the transmission line. This control signal is applied to an amplifying network which varies the amplification of signals transmitted through the transmission line in accordance with the magnitude of that control signal, and thereby automatically adjusts the repeater for operation with any transmission line to which it is connected.

Abstract: 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 contol signal which is a function of the a-c losses of the transmission line. 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.

Abstract: A circuit for providing a regulated a-c or d-c output voltage from an unregulated a-c input voltage. A series inductance is connected between the regulator input and the regulator output to support the difference in voltage between the unregulated a-c input voltage and the regulated a-c or d-c output voltage. A controllable shunt reactance is connected to the source of input voltage, through the series inductance, to vary the current through and the voltage across the series inductance. Control circuitry controls the magnitude and the capacitive/inductive character of the current which the shunt reactance draws through the line inductance, as required, to establish and maintain the regulated output voltage at the desired output current.

Abstract: A circuit for varying the amplification afforded to a-c signals transmitted through a transmission line in accordance with the length of that transmission line. Circuitry is provided which establishes a control signal which is a function of the a-c losses of the transmission line. This control signal is applied to an amplifying network which varies the amplification of signals transmitted through the transmission line in accordance with the magnitude of that control signal, and thereby automatically adjusts the repeater for operation with any transmission line to which it is connected.

Abstract: 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. 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.

Abstract: A circuit for providing a regulated a-c or d-c output voltage from an unregulated a-c input voltage. A series inductance is connected between the regulator input and the regulator output to support the difference in voltage between the unregulated a-c input voltage and the regulated a-c or d-c output voltage. A controllable shunt reactance is connected to the source of input voltage, through the series inductance, to vary the current through and the voltage across the series inductance. Control circuitry controls the magnitude of the current which the shunt reactance draws through the line inductance, as required, to establish and maintain the regulated output voltage at the desired output current.

Abstract: A circuit for reducing or eliminating the effect of the stray capacitance of the windings of a transformer on signals coupled through that transformer. Circuitry is provided for generating voltages and currents which simulate the presence of a negative capacitance and for coupling those voltages and currents to a transformer in cancelling relationships to the stray capacitance thereof. Circuitry is also provided for imposing an upper frequency limit beyond which capacitance cancellation will not occur. The upper frequency limit stabilizes the circuitry and allows signal transmission to be limited to a predetermined desired band of frequencies.