Patent US3345826A successfully refreshed from Google Patents.
Patent US4071713A successfully refreshed from Google Patents.
US4071713A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone speech network
Assignee: Nortel Networks Ltd
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Filing: 1976-12-27
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Granted: 1978-01-31
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Expires: 1996-12-27
Abstract
Abstract An electronic circuit, for connecting a transmitter and receiver to a telephone line. The circuit operates on very low operating voltages from the line which allows parallel operation with a conventional set on long-loop applications. In its functional form, the circuit utilizes a bridge configuration having transistors in two of its legs, driven by the transmitter output, thereby eliminating the usual bridge balancing resistors therefrom and their concomitant operating voltage drops thereacross.
Inventors
- 👤 Mevhibe Gulay Sencer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:03
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/58; H04M1/585; H04M1/60; H04M1/6025; H04M1/738; H04M1/76
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
149 words
A telephone speech network for connecting a transmitter and receiver to a telephone line, comprising: a plurality of transistors each having their emitter-collectors effectively connected in shunt across said telephone line for providing a signal varying impedance across the line terminals of the network; a line powered transmit amplifier for coupling the output of said transmitter to the base of each of the plurality of transistors, the emitter-collector of one of said transistors being connected in series with the input to a line powered receive amplifier across the telephone line; a balancing impedance connected in shunt with the emitter-collector of said one transistor for coupling receive signal currents from said line to said receive amplifier input and in conjunction with said one transistor to control the sidetone level of the transmit signals coupled to said input; and said receive amplifier coupling the amplified received signal currents to said receiver.
Claim 2
Dependent Claim
149 words
A telephone speech network for connecting a transmitter and receiver to a telephone line, comprising: a plurality of transistors each having their emitter-collectors effectively connected in shunt across said telephone line for providing a signal varying impedance across the line terminals of the network; a line powered transmit amplifier for coupling the output of said transmitter to the base of each of the plurality of transistors, the emitter-collector of one of said transistors being connected in series with the input to a line powered receive amplifier across the telephone line; a balancing impedance connected in shunt with the emitter-collector of said one transistor for coupling receive signal currents from said line to said receive amplifier input and in conjunction with said one transistor to control the sidetone level of the transmit signals coupled to said input; and said receive amplifier coupling the amplified received signal currents to said receiver.
Claim 3
Dependent Claim
69 words
A telephone speech network as defined in claim 1 in which the input to said receive amplifier comprises a diode connected in series aiding with said one transistor and in which the input to the receive amplifier comprises a further transistor having a base-emitter connected directly in shunt with said diode whereby the collector signal current of said further transistor is substantially the same as that of said diode.
Claim 4
Dependent Claim
22 words
A telephone speech network as defined in claim 1 which includes a terminating resistance effectively connected in shunt with said telephone line.
Claim 5
Dependent Claim
74 words
A telephone speech network as defined in claim 3 in which the ratio of transmit signal currents is substantially equal to: ##EQU3## where: i B = the transmit signal current from said one transistor, i T = the transmit signal currents from the balance of said plurality of transistors, Zl = the impedance of the telephone line, R1 = the resistance of said terminating resistance, and Zn = the impedance of said balancing impedance.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-30 | 1981-08-01 | 1982-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-30 | 1985-08-01 | 1986-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-30 | 1989-08-01 | 1990-01-31 | $7700.00 | Window Closed / Lapsed |