Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
144 words
Telecommunication line circuit including a DC loop resistance synthesizing circuit, said line circuit comprising: a Herter bridge, two line wires coupled to the Herter bridge, two line amplifiers for providing a synthesized feed voltage across the two line wires, a synthesized resistance in each said line wire, and a distinct line potential for each said line wire, a sense amplifier coupled to the Herter bridge for producing a sense voltage proportional to a current flowing in the line wires, bias means responsive to the sense voltage for providing a distinct respective bias voltage for each of the two line amplifiers, battery means for supplying a battery supply voltage, and a converter responsive to the bias means for converting the battery supply voltage to a common supply voltage for the two line amplifiers which is a combination of the two respective said distinct bias voltages.
Claim 2
Dependent Claim
144 words
Telecommunication line circuit including a DC loop resistance synthesizing circuit, said line circuit comprising: a Herter bridge, two line wires coupled to the Herter bridge, two line amplifiers for providing a synthesized feed voltage across the two line wires, a synthesized resistance in each said line wire, and a distinct line potential for each said line wire, a sense amplifier coupled to the Herter bridge for producing a sense voltage proportional to a current flowing in the line wires, bias means responsive to the sense voltage for providing a distinct respective bias voltage for each of the two line amplifiers, battery means for supplying a battery supply voltage, and a converter responsive to the bias means for converting the battery supply voltage to a common supply voltage for the two line amplifiers which is a combination of the two respective said distinct bias voltages.
Claim 3
Dependent Claim
54 words
Telecommunication line circuit as claimed in claim 1, wherein said bias means has a transducer for combining the respective distinct bias voltages, and said converter is a switched mode DC/DC converter which is fed by the battery means and is responsive to a DC voltage representative of a DC current through the line wires.
Claim 4
Dependent Claim
39 words
Telecommunication line circuit as claimed in claim 1, further comprising at least one push-pull signal source driving the inputs of the two line amplifiers, with four resistances coupling each said source to respective inputs of the two line amplifiers.
Claim 5
Dependent Claim
36 words
Telecommunication line circuit as claimed in claim 1, wherein the bias means comprises summing means at its output to add a first said bias potential to said sense voltage to produce a second said bias potential.
Claim 6
Dependent Claim
55 words
Telecommunication line circuit as claimed in claim 4, wherein said bias means further comprises an operational amplifier with identical impedance and gating circuits at its inverting and non-inverting inputs for varying the gain of the amplifier while keeping identical impedance input circuits, one connected to the input signal and the other to the reference potential.
Claim 7
Dependent Claim
20 words
Telecommunication line circuit as claimed in claim 4, wherein the two bias potentials are added to produce said supply voltage.
Claim 8
Dependent Claim
120 words
Telecommunication line circuit as claimed in claim 6, wherein said converter is a switched mode DC/DC converter having a transducer fed by the battery means for combining the respective distinct bias voltages, said bias means is responsive to a DC voltage representative of a DC current through the line wires, each of the two bias potentials are added through two summing inputs of a differential summing amplifier part of a feedback loop associated with the switched mode DC/DC converter and the output of the switched mode DC/DC converter as well as a voltage of the order of twice one said bias potentials is added through two further summing inputs having polarities opposite to those of the first two summing inputs.
Claim 9
Dependent Claim
33 words
Telecommunication line circuit as claimed in claim 1, wherein said bias means produces a respective output voltage having said respective bias potential with reference to a fixed potential pole of said supply voltage.
Claim 10
Dependent Claim
17 words
Telecommunication line circuit as claimed in claim 8 wherein said bias means comprises a low pass filter.
Claim 11
Dependent Claim
61 words
Telecommunication line circuit as claimed in claim 9, wherein said bias means comprises summing means at a first output to add a second bias potential at a second output to said sense voltage so as to produce said first bias potential, and means are provided to vary the response of said low pass filter including summing means at said first output.
Claim 12
Dependent Claim
38 words
Telecommunication line circuit as claimed in claim 1, wherein a set of four controlled gates couple the two bias potentials to the two line amplifiers with only two said gates leading to different said amplifiers being simultaneously unblocked.
Claim 13
Dependent Claim
97 words
Telecommunication line circuit as claimed in claim 11, wherein said bias means comprises: summing means at a first output to add a second said bias potential to said sense voltage so as to produce said first bias potential, and an absolute value operational amplifier having identical impedance circuits at its inverting and non-inverting inputs and including gating means for inverting the sign of its output signal when the line amplifiers are inversely biassed, and gating means for modifying an absolute gain value, in accordance with the value of said synthesized resistance, by modifying the input impedance circuits.
Claim 14
Dependent Claim
85 words
Telecommunication line circuit as claimed in claim 11, further comprising a power down circuit for bringing the circuit into a power down mode, a second set of four controlled gates for coupling two low power fixed potentials to the two line amplifiers with only two said of said second set of gates leading to different amplifiers being simultaneously unblocked, and means operable in said power down mode for biassing said bias potentials to thereby prevent the operation of said first set of four controlled gates.
Claim 15
Dependent Claim
64 words
Telecommunication line circuit as claimed in claim 1, wherein said bias means comprises line feed resistance discriminating means having an input fed by a potentiometer connected in the DC loop synthesizing circuit when a non-standard line feed resistance value is desired, the input being alternatively connectable to one out of several selected potentials each of which corresponds to a distinct preset said synthesized resistance.
Claim 16
Dependent Claim
53 words
Telecommunication line circuit as claimed in claim 14, wherein the discriminating means has another input for a control bit and means responsive for one value of said control bit for disconnecting the potentiometer from the loop and replacing it by another potentiometer thereby enabling one or more additional synthesized resistances to be selected.