Battery-feed circuit for exchange

Claim 2

A battery-feed circuit for an exchange, comprising: a first wire; a second wire; a first reference resistor coupled to said first wire; a second reference resistor coupled to said second wire; signal supply means for supplying alternating and direct current signals to said first and second wires; first feedback means for feeding back alternating-current signals, and including first and second capacitors coupled to the first and second wires, respectively, so that alternating-current signals supplied to said first and second wires are fed back to said first and second wires via said first and second reference resistors, respectively, so as to provide a desired alternating-current terminating resistance; second feedback means for feeding back direct-current signals connected to the first and second wires, so that direct current voltage supplied to said first and second wires is fed back independently, with respect to said first and second wires, to the first and second wires via said first and second reference resistors, so as to provide a desired direct-current supplying resistance; and polarity reversal control signal generating means for controlling a polarity reversal of signals supplied to said first and second wires by supplying a polarity reversal control signal to said second feedback means.

Claim 3

A battery-feed circuit according to claim 1, wherein said second feedback means includes first and second direct-current feedback circuits coupled to said first and second wires, respectively.

Claim 4

A battery-feed circuit according to claim 1, wherein said first feedback means comprises one differential amplifier coupled to said first and second wires.

Claim 5

A battery-feed circuit according to claim 1, wherein said first feedback means comprises a first differential amplifier coupled to said first wire and a second differential amplifier coupled to said second wire.

Claim 6

A battery-feed circuit according to claim 2, wherein said polarity reversal means comprises first and second control means for inputting first and second polarity-reversal control signals to said first and second direct-current feedback circuits, respectively, sending the polarity-reversal control signals to said first and second wires and reversing a polarity of signals on said first and second wires.

Claim 7

A battery-feed circuit acording to claim 5, wherein the first and second control means each include inverting means for sending a noiseless polarity-reversal signal by inverting smoothly the polarity of the first and second polarity-reversal control signals.

Claim 8

A battery-feed circuit according to claim 1, further comprising means for supplying a sending voice signal to said first and second wires.

Claim 9

A battery-feed circuit according to claim 1, wherein said first and second feedback means comprise a pair of operational amplifiers respectively coupled to said first and second wires, respectively.

Claim 10

A battery-feed circuit according to claim 5, wherein said first feedback means, said second feedback means, and said first and second control means comprise a pair of operational amplifiers coupled to the first and second wires.

Claim 11

A battery-feed circuit according to claim 5, wherein said first and second feedback means comprise: a first amplifier, for supplying a speech current for the first line, having first and second input terminals, the first input terminal of said first amplifier coupled to the first wire and the second input terminal coupled to the second wire via said second capacitor; and a second amplifier, for supplying a speech current for the second line, having first and second input terminals, the first input terminal of second amplifier coupled to the second wire and the second input terminal of the second amplifier coupled to the second wire via said first capacitor.

Claim 12

A battery-feed circuit according to claim 10, wherein said first and second amplifiers are operational amplifiers.

Claim 13

A battery-feed circuit according to claim 10, wherein the first input terminals of said first and second amplifiers are noninverting input terminals, and the second input terminals thereof are inverting input terminals.

Claim 14

A battery-feed circuit according to claim 12, wherein said first and second amplifiers operate as a voltage follower circuit with respect to direct current signals present on said first and second wires, the direct current signals being positively fed back to said first and second wires via said first and second reference resistors, said first and second amplifiers operate as an alternating current positive feedback circuit with respect to a voice signal received between said first and second wires, the received voice signal being positively fed back to said first and second wires via said first and second reference resistors, and said first and second amplifiers do not respond to a common mode signal, said common mode signal being coupled to said first and second wires via said first and second reference resistors.

Claim 15

A battery-feed circuit according to claim 10, wherein the circuit further comprises means for generating first and second polarity-reversal control signals, the first polarity-reversal control signal being input to the first input terminal of said first amplifier, the second polarity-reversal control signal being input to the first input terminal of said second amplifier, so that a polarity reversal signal is sent to the first and second lines by controlling the first and second polarity-reversal control signals.

Claim 16

A battery-feed circuit according to claim 14, wherein said circuit includes means for sending a noiseless polarity-reversal signal by inverting the first and second polarity-reversal control signals.

Claim 17

A battery-feed circuit according to claim 10, wherein the circuit further comprises means for applying a sending voice signal between the first input terminals of said first and second amplifiers, so that said circuit sends the voice signal to the first and second lines.

Claim 18

A battery-feed circuit according to claim 10, wherein said circuit is formed so that the first reference resistance, first amplifier, first capacitance, and the interconnections thereof are identical to the second reference resistance, second amplifier, second capacitance, and the interconnections thereof, respectively.

Claim 19

A battery feed circuit for an exchange comprising: a first wire; a second wire; a first reference resistance connected to said first wire; a second reference resistance connected to said second wire; means for providing a DC voltage on said first and second wires; means for providing an AC signal on said first and second wires; first feedback means for feeding the AC signal provided on said first and second wires back to said first and second wires via said first and second reference resistances; and second feedback means for feeding back said DC voltage provided on said first and second wires, said second feedback means operating as a voltage follower circuit, to thereby feed said DC voltage independently, with respect to said first and second wires, back to said first and second wires via said first and second reference resistances.

Claim 20

A battery feed circuit for an exchange comprising: a first wire; a second wire; a first reference resistance connected to said first wire; a second reference resistance connected to said second wire; means for providing a DC voltage on said first and second wires; means for providing an AC signal on said first and second wires; first feedback means for feeding the AC signal provided on said first and second wires back to said first and second wires via said first and second reference resistances; and second feedback means for feeding back said DC voltage provided on said first and second wires, said second feedback means operating as a voltage follower circuit, to thereby feed said DC voltage independently, with respect to said first and second wires, back to said first and second wires via said first and second reference resistances.

Claim 21

A battery feed circuit according to claim 18, wherein said first and second feedback means comprise: a first amplifier, for supplying a speech current to said first wire, having first and second input terminals, the first input terminal of said first amplifier being coupled to said first wire; and a second amplifier, for supplying the speech current for said second wire, having first and second input terminals, the first input terminal of said second amplifier being coupled to said second wire, said first and second amplifiers operating as said voltage follower circuit with respect to the DC voltage on said first and second wires so tht the DC voltage is fed back to said first and second reference resistances by DC positive feedback, and said first and second amplifiers operating as an AC positive feedback circuit with respect to the AC signal, so that the AC signal is fed back to said first and second reference resistances by AC positive feedback.

Claim 22

A battery feed circuit according to claim 19, wherein the AC signal is a voice signal.

Claim 23

A battery feed circuit according to claim 19, further comprising means for generating a common mode signal, wherein said first feedback means further comprises: a first capacitance coupled between said first line and the second input terminal of said second amplifier; and a second capacitance coupled between said second line and the second input terminal of said first amplifier, so that said first and second capacitances cause said common mode signal to be terminated via said first and second reference resistances.

Claim 24

A battery feed circuit for an exchange, comprising: a first wire; a second wire; a first reference resistor coupled to said first wire; a second reference resistor coupled to said second wire; a first amplifier, supplying a speech current to said first line, having a first non-inverting input terminal coupled to said first wire and a second inverting input terminal; a second amplifier, supplying a speech current to the second wire, having a first non-inverting input terminal coupled to said second wire and a second inverting input terminal; a first capacitance coupled between said first wire and said second input terminal of the second amplifier; and a second capacitance coupled between said second wire and said second input terminal of the first amplifier, said first and second amplifiers operating as a voltage follower circuit with respect to direct current voltage on said first and second wires, so that the DC voltage is fed back to said first and second reference resistors by means of DC positive feedback, said first and second amplifiers operating in combination as an alternating current positive feedback circuit with respect to a received voice signal between said first and second wires, so that the received voice signal is fed back to said first and second reference resistors by means of an AC positive feedback, and said first and second amplifiers not responding to a common mode signal, so that the common mode signal is terminated to said first and second reference resistors.

Claim 25

A battery feed circuit for an exchange, comprising: a first wire; a second wire; a first reference resistor coupled to said first wire; a second reference resistor coupled to said second wire; a first amplifier, supplying a speech current to said first line, having a first non-inverting input terminal coupled to said first wire and a second inverting input terminal; a second amplifier, supplying a speech current to the second wire, having a first non-inverting input terminal coupled to said second wire and a second inverting input terminal; a first capacitance coupled between said first wire and said second input terminal of the second amplifier; and a second capacitance coupled between said second wire and said second input terminal of the first amplifier, said first and second amplifiers operating as a voltage follower circuit with respect to direct current voltage on said first and second wires, so that the DC voltage is fed back to said first and second reference resistors by means of DC positive feedback, said first and second amplifiers operating in combination as an alternating current positive feedback circuit with respect to a received voice signal between said first and second wires, so that the received voice signal is fed back to said first and second reference resistors by means of an AC positive feedback, and said first and second amplifiers not responding to a common mode signal, so that the common mode signal is terminated to said first and second reference resistors.

Claim 26

A battery feed circuit for an exchange comprising: a first wire; a second wire; a first reference resistor coupled to said first wire; a second reference resistor coupled to said second wire; a first amplifier for supplying a speech current to the first wire, having first and second input terminals, the first input terminal of said first amplifier coupled to said first wire; a second amplifier, for supplying a speech current to the second wire, having first and second input terminals, the first input terminal of said second amplifier coupled to the second wire; a first capacitance coupled between the first wire and the second input terminal of the second amplifier; a second capacitance coupled between the second wire and the second input terminal of the first amplifier; and means for generating first and second polarity reversal control signals, the first polarity reversal control signal being input to the first input terminal of said first amplifier, a second polarity reversal control signal being input to the first input terminal of said second amplifier, so that a polarity reversal signal is sent to the first and second wires by controlling the first and second polarity reversal control signals.

Claim 27

A battery feed circuit for an exchange comprising: a first wire; a second wire; a first reference resistor coupled to said first wire; a second reference resistor coupled to said second wire; a first amplifier for supplying a speech current to the first wire, having first and second input terminals, the first input terminal of said first amplifier coupled to said first wire; a second amplifier, for supplying a speech current to the second wire, having first and second input terminals, the first input terminal of said second amplifier coupled to the second wire; a first capacitance coupled between the first wire and the second input terminal of the second amplifier; a second capacitance coupled between the second wire and the second input terminal of the first amplifier; and means for generating first and second polarity reversal control signals, the first polarity reversal control signal being input to the first input terminal of said first amplifier, a second polarity reversal control signal being input to the first input terminal of said second amplifier, so that a polarity reversal signal is sent to the first and second wires by controlling the first and second polarity reversal control signals.

Claim 28

A battery feed circuit according to claim 23, wherein said circuit sends a noiseless polarity reversal signal by inverting the first and second polarity reversal control signals.

Claim 29

A battery feed circuit for an exchange, comprising: a first wire; a second wire; a first reference resistor coupled to said first wire; a second reference resistor coupled to said second wire; a first amplifier, supplying a speech current to said first wire, having a first non-inverting input terminal coupled to said first wire and a second inverting input terminal; a second amplifier, supplying a speech current to the second wire, having a first non-inverting input terminal coupled to said first wire and a second inverting input terminal; a first capacitance coupled between said first wire and said second input terminal of the second amplifier; and a second capacitance coupled between said second wire and said second input terminal of the first amplifier, said first and second amplifiers operating as a voltage follower circuit with respect to direct current voltage on said first and second wires, so that the DC voltage is fed back to said first and second reference resistors by means of DC positive feedback, said first and second amplifiers operating in combination as an alternating current positive feedback circuit with respect to a received voice signal between said first and second wires, so that the received voice signal is fed back to said first and second reference resistors by means of an AC positive feedback, and said first and second amplifiers not responding to a common mode signal, so that the common mode signal is terminated to said first and second reference resistor, said first reference resistors, said first amplifier, said first capacitance, and the innerconnections therebetween are connected identically as said second reference resistor, said second amplifier, said second capacitance and the innerconnections therebetween, respectively, whereby alternating current signals supplied to said first and second wires are fed back to said first and second wires via said first and second reference resistors, respectively, to provide a specific terminating impedance, and direct current voltages supplied to said first and second wires are fed back independently, with respect to said first and second wires, to said first and second wires via said first and second reference resistors, to provide a constant resistance feeding bridge.

Claim 30

A battery feed circuit for an exchange, comprising: a first wire; a second wire; a first reference resistor coupled to said first wire; a second reference resistor coupled to said second wire; a first amplifier, supplying a speech current to said first wire, having a first non-inverting input terminal coupled to said first wire and a second inverting input terminal; a second amplifier, supplying a speech current to the second wire, having a first non-inverting input terminal coupled to said first wire and a second inverting input terminal; a first capacitance coupled between said first wire and said second input terminal of the second amplifier; and a second capacitance coupled between said second wire and said second input terminal of the first amplifier, said first and second amplifiers operating as a voltage follower circuit with respect to direct current voltage on said first and second wires, so that the DC voltage is fed back to said first and second reference resistors by means of DC positive feedback, said first and second amplifiers operating in combination as an alternating current positive feedback circuit with respect to a received voice signal between said first and second wires, so that the received voice signal is fed back to said first and second reference resistors by means of an AC positive feedback, and said first and second amplifiers not responding to a common mode signal, so that the common mode signal is terminated to said first and second reference resistor, said first reference resistors, said first amplifier, said first capacitance, and the innerconnections therebetween are connected identically as said second reference resistor, said second amplifier, said second capacitance and the innerconnections therebetween, respectively, whereby alternating current signals supplied to said first and second wires are fed back to said first and second wires via said first and second reference resistors, respectively, to provide a specific terminating impedance, and direct current voltages supplied to said first and second wires are fed back independently, with respect to said first and second wires, to said first and second wires via said first and second reference resistors, to provide a constant resistance feeding bridge.

Claim 31

A battery feed circuit for an exchange comprising: a first wire; a second wire; a first reference resistance connected to said first wire; a second reference resistance connected to said second wire; means for providing a DC voltage on said first and second wires; means for providing an AC signal on said first and second wires; and feedback means for providing the DC voltage and the AC signal to said first and second reference resistances, comprising: a first amplifier, for supplying a speech current to said first wire, having first and second input terminals, the first input terminal of said first amplifier being coupled to said first wire; and a second amplifier, for supplying the speech current for said second wire, having first and second input terminals, the first input terminal of said second amplifier being coupled to said second wire, said first and second amplifiers operating as a voltage follower circuit with respect to the DC voltage on said first and second wires so that the DC voltage is fed back to said first and second reference resistances by DC positive feedback, and said first and second amplifiers operating as an AC positive feedback circuit with respect to the AC signal, so that the AC signal is fed back to said first and second reference resistances by AC positive feedback.

Claim 32

A battery feed circuit for an exchange comprising: a first wire; a second wire; a first reference resistance connected to said first wire; a second reference resistance connected to said second wire; means for providing a DC voltage on said first and second wires; means for providing an AC signal on said first and second wires; and feedback means for providing the DC voltage and the AC signal to said first and second reference resistances, comprising: a first amplifier, for supplying a speech current to said first wire, having first and second input terminals, the first input terminal of said first amplifier being coupled to said first wire; and a second amplifier, for supplying the speech current for said second wire, having first and second input terminals, the first input terminal of said second amplifier being coupled to said second wire, said first and second amplifiers operating as a voltage follower circuit with respect to the DC voltage on said first and second wires so that the DC voltage is fed back to said first and second reference resistances by DC positive feedback, and said first and second amplifiers operating as an AC positive feedback circuit with respect to the AC signal, so that the AC signal is fed back to said first and second reference resistances by AC positive feedback.

Claim 33

A battery feed circuit according to claim 26, wherein the AC signal is a voice signal.

Claim 34

A battery feed circuit according to claim 26 further comprising means for generating a common mode signal, wherein said feedback means further comprises: a feed capacitance coupled between said first wire and the second input terminal of said second amplifier; and a second capacitance coupled between said second wire and the second input terminal of said first amplifier, so that said first and second capacitances cause said common mode signal to be terminated via said first and second reference resistances.