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US5177485A
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Method of scrambling pal, secam and ntsc composite video signals and decoder of signals scrambled by this method
Assignee: Laboratoire Europeen de Recherches Electroniques Avancees SNC
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Filing: 1989-12-08
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Granted: 1993-01-05
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Expires: 2009-12-08
Abstract
Abstract The method of the invention consists in shifting (a) the start of the scrambled section of a composite video line of a television image with respect to the start of the useful part of that line.
Inventors
- 👤 Patrick Daniel
- 👤 Jean-Claude Guillon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:18
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167; H04N7/169; H04N7/1693
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
118 words
A method of processing PAL and SECAM composite video signals, comprising the steps of: scrambling the composite video signals by line permutation controlled by a pseudo-random sequence, wherein the pseudo-random sequence is based on a control word with an encoded value incorporated in the composite video signals, the scrambling comprising the step of shifting a start of a scrambed zone of a video signal segment of each line of the composite video signals with respect to a start of each line so that a beginning of video information is not subject to scrambling; descrambling the scrambled composite video signal by using the pseudo-random sequence which is identical and synchronized with the pseudo-random sequence used in the scrambling step.
Claim 2
Independent Claim
118 words
A method of processing PAL and SECAM composite video signals, comprising the steps of: scrambling the composite video signals by line permutation controlled by a pseudo-random sequence, wherein the pseudo-random sequence is based on a control word with an encoded value incorporated in the composite video signals, the scrambling comprising the step of shifting a start of a scrambed zone of a video signal segment of each line of the composite video signals with respect to a start of each line so that a beginning of video information is not subject to scrambling; descrambling the scrambled composite video signal by using the pseudo-random sequence which is identical and synchronized with the pseudo-random sequence used in the scrambling step.
Claim 3
Dependent Claim
22 words
The method according to claim 1, wherein the shifting of the start of the scrambled zone varies in the course of time.
Claim 4
Dependent Claim
21 words
The method according to claim 2, wherein the shifting of the start of the scrambled zone changes value every 40 ms.
Claim 5
Independent Claim
38 words
The method according to any one of claims 1-3 wherein a complete non-scrambled section of each useful line is delayed on transmission and this delay is equal to a duration of one line of the composite video signals.
Claim 6
Independent Claim
29 words
The method according to any one of claims 1-3, wherein interpolation samples are inserted on both sides of a break point in each line of the composite video signals.
Claim 7
Dependent Claim
65 words
A decoder for an image transmission system comprising: a receiver for receiving scrambled composite video signals; a descrambler for descrambling the scrambled composite video signals, the descrambler comprising in a parallel connection: two FIFO queues each acting as a delay line and having write/read counters and zero reset inputs, wherein the write/read counters are only accessible by the zero reset inputs; and a buffer register.
Claim 8
Dependent Claim
65 words
A decoder for an image transmission system comprising: a receiver for receiving scrambled composite video signals; a descrambler for descrambling the scrambled composite video signals, the descrambler comprising in a parallel connection: two FIFO queues each acting as a delay line and having write/read counters and zero reset inputs, wherein the write/read counters are only accessible by the zero reset inputs; and a buffer register.
Claim 9
Dependent Claim
24 words
The decoder according to claim 6, wherein the FIFO queues are of the NEC μ PD 41101 c-x type (where x=1, 2 or 3).
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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) | 1996-01-05 | 1996-07-06 | 1997-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-01-05 | 2000-07-06 | 2001-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-01-05 | 2004-07-06 | 2005-01-05 | $7700.00 | Window Closed / Lapsed |