Patent US3566285A successfully refreshed from Google Patents.
US3566285A
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US
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Pitch synchronous reduction of signal envelope
Assignee: AT&T Inc
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Filing: 1968-07-26
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Granted: 1971-02-23
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Expires: 1988-07-26
Abstract
Abstract BY REDUCING THE ENVELOPE OF A SIGNAL, SUCH AS A SPEECH SIGNAL, IN A NONLINEAR FASHION A MODIFIED SIGNAL IS PRODUCED WHICH, IN ADDITION TO BEING HIGHLY INTELLIGIBLE, EXHIBITS DESIRABLE PROPERTIES. PITCH SYNCHRONOUS GAPS, SMOOTHLY ESTABLISHED IN A REDUCED ENVELOPE SIGNAL IN PLACE OF INTERVALS OF LOW SIGNAL LEVELS, ARE EFFECTIVE IN ELIMINATING NOISE WHICH MASKS LOW LEVEL SIGNALS, REDUCING REVERBERATION, AND IN ADAPTING THE SIGNAL FOR MULTIPLEX TRANSMISSION. ENVELOPE REDUCTION IS EFFICIENTLY ACHIEVED BY CONTROLLABLY CENTER CLIPPING A SELECTED MOFULATION SIDEBAND OF A SIGNAL, FILTERING THE RESULTANT, AND RESTORING THE SIGNAL TO BASEBAND.
Inventors
- 👤 Manfred R Schroeder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:05
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/16; H04J3/1682; H04J3/1688; G; G10; G10L; G10L25/00
Claims Analysis
Total Claims: 0
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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) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |