US3157741A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Data transmission system
Assignee: AT&T Inc
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Filing: 1961-08-29
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Granted: 1964-11-17
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Expires: 1981-08-29
Abstract
No abstract record available.
Inventors
- 👤 William R Bennett
- 👤 Fritz E Froehlich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:34
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/227; H04L27/2275; H04L27/2276; H04L27/20; H04L27/2003; H04L27/2021; H04L27/2028; H04L27/233; H04L27/2334
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
155 words
IN A DATA COMMUNICATIONS SYSTEM IN WHICH BINARY DIGITAL DATA ARE ENCODED AT A SYNCHRONOUS RATE IN PAIRS AS RELATIVE PHASE SHIFTS OF A CARRIER WAVE IN MULTIPLES OF 45 ELECTRICAL DEGREES, MEANS FOR RECOVERING A SYNCHRONIZING SIGNAL FROM A CARRIER WAVE PHASE SHIFTED IN ACCORDANCE WITH BINARY DIGITAL DATA AT A SYNCHRONOUS RATE COMPRISING A SLOPE CIRCUIT OPERATING ON THE PHASE-SHIFTED CARRIER WAVE FOR DERIVING A SIGNAL REPRESENTATIVE OF THE TIME DERIVATIVE OF THE SYNCHRONOUS RATE OCCURING THEREIN, AN ENVELOPE DETECTOR FOR SEPARATING FROM THE TIME DERIVATIVE SIGNAL DERIVED IN SAID SLOPE CIRCUIT A FREQUENCY COMPONENT REPRESENTING SAID SYNCHRONOUS RATE AND OTHER FREQUENCY COMPONENTS INCLUDING THE FREQUENCY OF SAID CARRIER WAVE, A FULL-WAVE RECTIFIER FOR REMOVING POLARITY AMBIGUITIES FROM THE FREQUENCY COMPONENT AT SAID SYNCHRONOUS RATE SEPARATED BY SAID DETECTOR AND PRODUCING A UNIPOLAR OUTPUT, AND MEANS SMOOTHING THE UNIPOLAR OUTPUT OF SAID RECTIFIER INTO A SINGLE FREQUENCY WAVE INDICATIVE OF SAID SYNCHRONOUS RATE.
Claim 2
Dependent Claim
155 words
IN A DATA COMMUNICATIONS SYSTEM IN WHICH BINARY DIGITAL DATA ARE ENCODED AT A SYNCHRONOUS RATE IN PAIRS AS RELATIVE PHASE SHIFTS OF A CARRIER WAVE IN MULTIPLES OF 45 ELECTRICAL DEGREES, MEANS FOR RECOVERING A SYNCHRONIZING SIGNAL FROM A CARRIER WAVE PHASE SHIFTED IN ACCORDANCE WITH BINARY DIGITAL DATA AT A SYNCHRONOUS RATE COMPRISING A SLOPE CIRCUIT OPERATING ON THE PHASE-SHIFTED CARRIER WAVE FOR DERIVING A SIGNAL REPRESENTATIVE OF THE TIME DERIVATIVE OF THE SYNCHRONOUS RATE OCCURING THEREIN, AN ENVELOPE DETECTOR FOR SEPARATING FROM THE TIME DERIVATIVE SIGNAL DERIVED IN SAID SLOPE CIRCUIT A FREQUENCY COMPONENT REPRESENTING SAID SYNCHRONOUS RATE AND OTHER FREQUENCY COMPONENTS INCLUDING THE FREQUENCY OF SAID CARRIER WAVE, A FULL-WAVE RECTIFIER FOR REMOVING POLARITY AMBIGUITIES FROM THE FREQUENCY COMPONENT AT SAID SYNCHRONOUS RATE SEPARATED BY SAID DETECTOR AND PRODUCING A UNIPOLAR OUTPUT, AND MEANS SMOOTHING THE UNIPOLAR OUTPUT OF SAID RECTIFIER INTO A SINGLE FREQUENCY WAVE INDICATIVE OF SAID SYNCHRONOUS RATE.
References Cited (Backward Citations)
US2979566A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1967-11-17 | 1968-05-18 | 1968-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-11-17 | 1972-05-18 | 1972-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-11-17 | 1976-05-18 | 1976-11-17 | $7700.00 | Window Closed / Lapsed |