US3818140A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone line receiver and transmitter
Assignee: Bendix Corp
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Filing: 1972-11-17
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Granted: 1974-06-18
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Expires: 1992-11-17
Abstract
Abstract A telephone line receiver transmitter designed to an interface with a 600 ohm telephone line through a standard telephone system data coupler uses a single operational amplifier and operates without switching. The operational amplifier includes a 600 ohm feedback resistor with the telephone system data coupler being connected across the resistor.
Inventors
- 👤 N Green
- 👤 W Vergara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:14
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/54; H04B1/58; H04B1/586; H04M; H04M1/00; H04M1/60
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
162 words
A line transmitter and receiver for communicating information with a telephone line through a telephone system data coupler which includes a transformer having a first winding which is connected to the line transmitter and receiver and a second winding which is connected to the telephone line comprising: an operational amplifier having a non-inverting input terminal, an inverting input terminal, and an output terminal; a common terminal; another terminal upon which information to be transmitted is impressed; resistance means for connecting said another terminal to said common terminal; means for connecting a point interior of said resistance means to said non-inverting input terminal; a first resistor connected between said inverting input terminal and said common terminal; a feedback resistor connected betWeen said operational amplifier output terminal and said inverting input terminal, said first winding being connected across said feedback resistor, and; means for effectively connecting said operational amplifier output terminal to said common terminal, information received from said telephone lines thereby appearing thereacross.
Claim 2
Dependent Claim
162 words
A line transmitter and receiver for communicating information with a telephone line through a telephone system data coupler which includes a transformer having a first winding which is connected to the line transmitter and receiver and a second winding which is connected to the telephone line comprising: an operational amplifier having a non-inverting input terminal, an inverting input terminal, and an output terminal; a common terminal; another terminal upon which information to be transmitted is impressed; resistance means for connecting said another terminal to said common terminal; means for connecting a point interior of said resistance means to said non-inverting input terminal; a first resistor connected between said inverting input terminal and said common terminal; a feedback resistor connected betWeen said operational amplifier output terminal and said inverting input terminal, said first winding being connected across said feedback resistor, and; means for effectively connecting said operational amplifier output terminal to said common terminal, information received from said telephone lines thereby appearing thereacross.
Claim 3
Dependent Claim
44 words
A line transmitter and receiver as recited in claim 1 wherein said information to be communicated occurs within an audio frequency range and wherein said first winding is a much higher impedance than the impedance of said feedback resistor at said audio frequency range.
Claim 4
Dependent Claim
18 words
A line transmitter and receiver as recited in claim 2 wherein said feedback resistor is approximately 600 ohms.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |