Patent US4587507A successfully refreshed from Google Patents.
Patent US3914560A successfully refreshed from Google Patents.
US3914560A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-adjusting repeater for voice frequency telephone transmission systems
Assignee: Superior Continental Corp
•
Filing: 1971-10-13
•
Granted: 1975-10-21
•
Expires: 1991-10-13
Abstract
Abstract Disclosed is a telephone automatic gain control repeater for automatically adjusting a.c. signal gain to compensate for loop transmission loss. An embodiment of the disclosed repeater contains two hybrids, connected together through a controllable attenuator and an amplifier, the controllable attenuator having means for variably attenuating a.c. signals passing there through. One hybrid is connected to a transmission line; the other is connected to and passes a.c. signals from a telephone central office. The means for variably attenuating a.c. signals is responsive to a d.c. current flow through at least a portion of the controllable attenuator. A control means is provided for regulating the d.c. current flow in the controllable attenuator and bridges a resistive means in series with a transmission line. The control means is responsive to the voltage drop across the resistive means. When there is a decrease in voltage across the resistive means (increased resistance on the transmission line) the control means passes a proportionally decreased d.c. current flow through it and the controllable attenuator, thereby decreasing its attenuation to a.c. signals passing there through.
Inventors
- 👤 Clifford E Greene
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:05
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/04
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
139 words
In a voice frequency telephone transmission system, a voice frequency repeater having a signal-transmitting circuit which includes an amplifier for amplifying voice frequency signals and controllable means for varying the gain which the circuit provides between its input and output terminals, a telephone, a loaded two-conductor transmission line providing a connection between said circuit and said telephone for transmitting the voice frequency signals, said repeater being connected to the central office end of said line, and means electrically connected to said line and said controllable means and controlling said controllable means to provide said circuit with an amount of gain that maintains the transmission loss of said signals approximately constant regardless of the length of said line or the gauge of the transmission line conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 2
Dependent Claim
139 words
In a voice frequency telephone transmission system, a voice frequency repeater having a signal-transmitting circuit which includes an amplifier for amplifying voice frequency signals and controllable means for varying the gain which the circuit provides between its input and output terminals, a telephone, a loaded two-conductor transmission line providing a connection between said circuit and said telephone for transmitting the voice frequency signals, said repeater being connected to the central office end of said line, and means electrically connected to said line and said controllable means and controlling said controllable means to provide said circuit with an amount of gain that maintains the transmission loss of said signals approximately constant regardless of the length of said line or the gauge of the transmission line conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 3
Dependent Claim
200 words
In a voice frequency telephone transmission system having a telephone, a voice frequency repeater adapted to be connected to a central office for passing voice frequency signals, a loaded two-conductor transmission line providing a connection between said repeater and said telephone for transmitting the voice frequency signals between said telephone and said repeater, said telephone being connected across the conductors of said line, and a d. c. voltage source electrically connected to said line and feeding direct current through the loop defined by the conductors of said line and said telephone to provide said direct current with a magnitude which is closely indicative of the reciprocal of the d.c. resistance of said loop, a variable gain amplifier circuit forming a part of said repeater for amplifying said signals in each direction of transmission, and means under the control of the magnitude of said direct current for making the gain of said amplifier circuit a function of the resistance of said loop to maintain the transmission loss of said signals approximately constant regardless of the length of said line or the gauge of said transmission line conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 4
Dependent Claim
200 words
In a voice frequency telephone transmission system having a telephone, a voice frequency repeater adapted to be connected to a central office for passing voice frequency signals, a loaded two-conductor transmission line providing a connection between said repeater and said telephone for transmitting the voice frequency signals between said telephone and said repeater, said telephone being connected across the conductors of said line, and a d. c. voltage source electrically connected to said line and feeding direct current through the loop defined by the conductors of said line and said telephone to provide said direct current with a magnitude which is closely indicative of the reciprocal of the d.c. resistance of said loop, a variable gain amplifier circuit forming a part of said repeater for amplifying said signals in each direction of transmission, and means under the control of the magnitude of said direct current for making the gain of said amplifier circuit a function of the resistance of said loop to maintain the transmission loss of said signals approximately constant regardless of the length of said line or the gauge of said transmission line conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 5
Dependent Claim
71 words
The voice frequency telephone transmission system defined in claim 2 wherein said amplifier circuit comprises fixed gain amplifier means for amplifying said signals and controllable attenuator means for variably attenuating said signals, and wherein said gain controlling means comprises a control circuit connected to said attenuator means, said attenuator Means being controlled by said control circuit to attenuate said signals by an amount that is a function of said direct current.
Claim 6
Dependent Claim
216 words
The voice frequency telephone transmission system defined in claim 2 wherein said amplifier circuit comprises first and second fixed gain amplifiers and first and second controllable attenuators respectively connected to said first and second amplifiers, said first amplifier and said first attenuator respectively amplifying and attenuating the voice frequency signals being transmitted in one direction, and said second amplifier and said second attenuator respectively amplifying and attenuating the voice frequency signals being transmitted in the opposite direction, and wherein said gain controlling means comprises a component having a resistance connected between said source and at least one of the conductors of said line to provide a voltage drop that varies in accordance with magnitude of said direct current, and a control circuit connected to said line and to said first and second attenuators for providing for a regulated flow of direct current through a control portion of each of said attenuators, said control circuit being effective to provide the direct current flowing through each attenuator control portion with a magnitude that is a function of said voltage drop, and each of said attenuators being effective to attenuate the voice frequency signals for its associated direction of transmission by a magnitude that is a function of the magnitude of the direct current flowing through its control portion.
Claim 7
Independent Claim
239 words
A method of rendering a voice frequency repeater self-adjusting to different telephone transmission line lengths and/or different transmission line conductor gauges in a voice frequency telephone transmission system in which a two-conductor transmission line provides a connection between a telephone and said repeater for transmitting signals in opposite directions, in which said telephone is connected across the conductors of said line, in which said repeater is connected to the central office end of said transmission line, and in which amplifiers in said repeater have fixed pre-selected gains for amplifying said signals in both directions of transmission, said method comprising the steps of loading said transmission line so that the transmission loss of signals transmitted by said line is substantially exclusively a function of resistance, feeding a direct current through the loop defined by the conductors of said line and said telephone to provide said direct current with a magnitude which is closely indicative of the reciprocal of the resistance of said loop, sensing the magnitude of said direct current, and variably attenuating said signals in each direction of transmission at said repeater by an amount determined by the sensed magnitude of said direct current to provide said repeater with a net gain that maintains the transmission loss of said signals approximately constant regardless of the length of said line or the gauge of said conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 8
Independent Claim
239 words
A method of rendering a voice frequency repeater self-adjusting to different telephone transmission line lengths and/or different transmission line conductor gauges in a voice frequency telephone transmission system in which a two-conductor transmission line provides a connection between a telephone and said repeater for transmitting signals in opposite directions, in which said telephone is connected across the conductors of said line, in which said repeater is connected to the central office end of said transmission line, and in which amplifiers in said repeater have fixed pre-selected gains for amplifying said signals in both directions of transmission, said method comprising the steps of loading said transmission line so that the transmission loss of signals transmitted by said line is substantially exclusively a function of resistance, feeding a direct current through the loop defined by the conductors of said line and said telephone to provide said direct current with a magnitude which is closely indicative of the reciprocal of the resistance of said loop, sensing the magnitude of said direct current, and variably attenuating said signals in each direction of transmission at said repeater by an amount determined by the sensed magnitude of said direct current to provide said repeater with a net gain that maintains the transmission loss of said signals approximately constant regardless of the length of said line or the gauge of said conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 9
Dependent Claim
189 words
In a voice frequency telephone system having a telephone, a voice frequency repeater, a two-conductor transmission line providing a connection between said telephone and said repeater for transmitting signals between said repeater and said telephone, said line being loaded so that the transmission loss of transmitted signals is substantially exclusively a function of resistance, said repeater being connected to the central office end of said line and having a signal-transmitting circuit which has a variable gain and which includes an amplifier for amplifying said signals, a d.c. voltage source connected to the central office end of said line for feeding direct current through the loop defined by the conductors of said line and said telephone, and a control circuit connected to said line and to said signal-transmitting circuit and controlling the gain of said signalling-transmitting circuit as a fUnction of the magnitude of said direct current to provide said gain with a value which maintains the transmission loss of said signals approximately constant regardless of the length of said line or gauge of said conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 10
Dependent Claim
189 words
In a voice frequency telephone system having a telephone, a voice frequency repeater, a two-conductor transmission line providing a connection between said telephone and said repeater for transmitting signals between said repeater and said telephone, said line being loaded so that the transmission loss of transmitted signals is substantially exclusively a function of resistance, said repeater being connected to the central office end of said line and having a signal-transmitting circuit which has a variable gain and which includes an amplifier for amplifying said signals, a d.c. voltage source connected to the central office end of said line for feeding direct current through the loop defined by the conductors of said line and said telephone, and a control circuit connected to said line and to said signal-transmitting circuit and controlling the gain of said signalling-transmitting circuit as a fUnction of the magnitude of said direct current to provide said gain with a value which maintains the transmission loss of said signals approximately constant regardless of the length of said line or gauge of said conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 11
Dependent Claim
235 words
In a voice frequency telephone transmission system having a telephone, a voice frequency repeater, a two-conductor transmission line providing a connection between said repeater and said telephone for transmitting voice frequency signals in at least one pre-selected direction of transmission, said repeater being connected to the central office end of said line, and said telephone being connected across the conductors of said line, said transmission line being loaded to make the transmission loss of signals transmitted by said line substantially exclusively a function of resistance, a d.c. voltage source electrically connected to said line to feed direct current through the loop defined by the transmission line conductors and said telephone to provide said direct current with a magnitude which is closely indicative of the reciprocal of the resistance of said loop, an amplifier forming a part of said repeater and providing a predetermined gain for amplifying said signals, means for sensing the magnitude of said direct current, and a controllable attenuator forming a part of said repeater and controlled by said sensing means for attenuating said signals by an amount determined by the magnitude of said direct current to provide said repeater with a net gain that maintains the transmission loss of said signals approximately constant regardless of the length of said line or the gauge of said transmission line conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 12
Dependent Claim
235 words
In a voice frequency telephone transmission system having a telephone, a voice frequency repeater, a two-conductor transmission line providing a connection between said repeater and said telephone for transmitting voice frequency signals in at least one pre-selected direction of transmission, said repeater being connected to the central office end of said line, and said telephone being connected across the conductors of said line, said transmission line being loaded to make the transmission loss of signals transmitted by said line substantially exclusively a function of resistance, a d.c. voltage source electrically connected to said line to feed direct current through the loop defined by the transmission line conductors and said telephone to provide said direct current with a magnitude which is closely indicative of the reciprocal of the resistance of said loop, an amplifier forming a part of said repeater and providing a predetermined gain for amplifying said signals, means for sensing the magnitude of said direct current, and a controllable attenuator forming a part of said repeater and controlled by said sensing means for attenuating said signals by an amount determined by the magnitude of said direct current to provide said repeater with a net gain that maintains the transmission loss of said signals approximately constant regardless of the length of said line or the gauge of said transmission line conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 13
Independent Claim
233 words
A method of rendering a voice frequency amplifying repeater self-adjusting to different telephone transmission line lengths and/or different transmission line conductor gauges in a voice frequency telephone transmission system in which a transmission line having a pair of conductors provides a connection between a telephone and said repeater for transmitting voice frequency signals in at least one preselected direction of transmission, in which said telephone is connected across said conductors, in which an amplifying circuit of the repeater provides a predetermined gain for amplifying said voice frequency signals, and in which said repeater is connected to the central office end of said line, said method comprising the steps of loading said transmission line to make the transmission loss of signals transmitted by said line substantially exclusively a function of resistance, feeding a direct current through the loop defined by said conductors and said telephone to provide said direct current with a magnitude that is closely indicative of the reciprocal of the resistance of said loop, and attenuating said voice frequency signals at said repeater by an amount that is a function of the magnitude of said direct current to provide said repeater with a net gain that maintains the transmission loss of said signals approximately constant regardless of the length of said line or the gauge of said conductors whenever the loop resistance of said line is within a predetermined range of resistances.
Claim 14
Independent Claim
233 words
A method of rendering a voice frequency amplifying repeater self-adjusting to different telephone transmission line lengths and/or different transmission line conductor gauges in a voice frequency telephone transmission system in which a transmission line having a pair of conductors provides a connection between a telephone and said repeater for transmitting voice frequency signals in at least one preselected direction of transmission, in which said telephone is connected across said conductors, in which an amplifying circuit of the repeater provides a predetermined gain for amplifying said voice frequency signals, and in which said repeater is connected to the central office end of said line, said method comprising the steps of loading said transmission line to make the transmission loss of signals transmitted by said line substantially exclusively a function of resistance, feeding a direct current through the loop defined by said conductors and said telephone to provide said direct current with a magnitude that is closely indicative of the reciprocal of the resistance of said loop, and attenuating said voice frequency signals at said repeater by an amount that is a function of the magnitude of said direct current to provide said repeater with a net gain that maintains the transmission loss of said signals approximately constant regardless of the length of said line or the gauge of said conductors whenever the loop resistance of said line is within a predetermined range of resistances.
References Cited (Backward Citations)
US1973504A
Cited
US2117708A
Cited
US2818470A
Cited
US2870271A
Cited
US3187104A
Cited
US3330912A
Cited
US3578914A
Cited
US3660609A
Cited
US3602648A
Cited
US3689711A
Cited
US3781481A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-20 | 1979-04-21 | 1979-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-20 | 1983-04-21 | 1983-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-20 | 1987-04-21 | 1987-10-21 | $7700.00 | Window Closed / Lapsed |