US4112262A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone station repeater
Assignee: AT&T Inc
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Filing: 1977-07-26
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Granted: 1978-09-05
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Expires: 1997-07-26
Abstract
Abstract A telephone station repeater is disclosed which will provide bidirectional gain in a long telephone loop at the customer's station. The repeater is powered from the central office battery over the loop and provides gain with very small power consumption and virtually no power consumption when not in use. The station repeater comprises a negative impedance amplifier including a shunt negative impedance, a series negative impedance and an autotransformer connected in a π configuration. The shunt converter is disconnected when the telephone set is on-hook. The autotransformer provides impedance matching to the telephone set.
Inventors
- 👤 Kenneth Erwin Stiefel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:32
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/16; H04B3/18
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
51 words
A negative impedance bidirectional amplifier for insertion at the subscriber end of a telephone line, said amplifier comprising: a shunt negative impedance converter; a series negative impedance converter; and a shunt autotransformer; said negative impedance converters and said autotransformer being connected in a π configuration with respect to said telephone line.
Claim 2
Dependent Claim
51 words
A negative impedance bidirectional amplifier for insertion at the subscriber end of a telephone line, said amplifier comprising: a shunt negative impedance converter; a series negative impedance converter; and a shunt autotransformer; said negative impedance converters and said autotransformer being connected in a π configuration with respect to said telephone line.
Claim 3
Dependent Claim
28 words
The negative impedance amplifier according to claim 1 further including: a current responsive switch responsive to currents in said telephone line for activating said shunt negative impedance converter.
Claim 4
Dependent Claim
30 words
The negative impedance amplifier according to claim 2 wherein said current responsive switch operates above a preselected current threshold to connect said shunt negative impedance converter across said telephone line.
Claim 5
Dependent Claim
21 words
The negative impedance amplifier according to claim 1 further including: a telephone set connected across the partial winding of said autotransformer.
Claim 6
Dependent Claim
46 words
The negative impedance amplifier according to claim 4 wherein said series negative impedance converter is biased to operate in a region of positive impedance when said telephone set is on-hook, and biased to operate in a region of negative impedance when said telephone set is off-hook.
Claim 7
Dependent Claim
88 words
A telephone station repeater energized from the central office battery over a long telephone loop, said repeater comprising: a shunt negative impedance converter, a current responsive switch for connecting said shunt negative impedance converter across said telephone loop; a series negative impedance converter connected to one end to said current responsive switch; an autotransformer connected at the other end of said series negative impedance converter and in shunt with said telephone loop; and at least one telephone set connected across a portion of the winding of said autotransformer.
Claim 8
Dependent Claim
88 words
A telephone station repeater energized from the central office battery over a long telephone loop, said repeater comprising: a shunt negative impedance converter, a current responsive switch for connecting said shunt negative impedance converter across said telephone loop; a series negative impedance converter connected to one end to said current responsive switch; an autotransformer connected at the other end of said series negative impedance converter and in shunt with said telephone loop; and at least one telephone set connected across a portion of the winding of said autotransformer.
Claim 9
Dependent Claim
18 words
The telephone station repeater according to claim 6 further including: a capacitor connected in series with said autotransformer.
Claim 10
Dependent Claim
30 words
The telephone station repeater according to claim 6 wherein said current responsive switch is disabled when said telephone set is on-hook and is enabled when said telephone set is off-hook.
Claim 11
Dependent Claim
43 words
The telephone station repeater according to claim 6 wherein said series negative impedance converter is biased in a region of positive impedance when said telephone set is on-hook, and is biased in a region of negative impedance when said telephone set is off-hook.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-04 | 1982-03-06 | 1982-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-04 | 1986-03-06 | 1986-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-04 | 1990-03-06 | 1990-09-05 | $7700.00 | Window Closed / Lapsed |