US4551580A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Time-frequency scrambler
Assignee: Nokia Bell Labs
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Filing: 1982-11-22
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Granted: 1985-11-05
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Expires: 2002-11-22
Abstract
Abstract Subband signals are formed each corresponding to a portion of an input signal frequency spectrum. The subband signals are partitioned into subband time segments. The subband time segment signals are permuted. The permuted signals are combined to form a scrambled signal.
Inventors
- 👤 Richard V. Cox
- 👤 Nuggehally S. Jayant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:08
CPC Classifications
H; H04; H04K; H04K1/00
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
46 words
prescribed signal. 20. The method of claim 16 wherein the subband sample signal forming step comprises applying the digital sample signals to a quadrature mirror filter and the inverse permuted block combining step comprises applying the inverse permuted digital signal blocks to a quadrature mirror filter.
References Cited (Backward Citations)
US4266095A
Cited
US3773977A
Cited
US4068094A
Cited
US3970790A
Cited
US4099027A
Cited
US4149035A
Cited
US4232193A
Cited
US4221931A
Cited
US4278840A
Cited
US4443660A
Cited
US4433211A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-11-04 | 1989-05-06 | 1989-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-04 | 1993-05-06 | 1993-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-04 | 1997-05-06 | 1997-11-05 | $7700.00 | Window Closed / Lapsed |