US4633310A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and device for secure transmission and of television pictures
Assignee: Telediffusion de France ets Public de Diffusion
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Filing: 1984-03-19
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Granted: 1986-12-30
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Expires: 2004-03-19
Abstract
Abstract A process for scrambling and unscrambling video signals during transmission begins with a sampled line of video signals. The line is divided into adjacent segments, each of which has at least two samples. The dividing point between the two segments is defined in a pseudo-random manner, synchronously in the transmission and the reception. One of the segments is transmitted in a reversed manner. Upon reception, it is returned into its original direction.
Inventors
- 👤 Christian J. F. Gautier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:14
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167; H04N7/169; H04N7/1696
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
89 words
A process for scrambling and unscrambling a useful signal comprising a sampled line of video signals, said process comprising the steps of: (a) dividing at least one part of said useful signal into segments which are adjacent, each one of the segments comprising at least two samples, the dividing point between the two segments being defined in a pseudo-random manner synchronously in the transmission and the reception; (b) transmitting one of the segments in a reversed manner; and (c) upon reception, returning said reversed segment into the original direction.
Claim 2
Dependent Claim
89 words
A process for scrambling and unscrambling a useful signal comprising a sampled line of video signals, said process comprising the steps of: (a) dividing at least one part of said useful signal into segments which are adjacent, each one of the segments comprising at least two samples, the dividing point between the two segments being defined in a pseudo-random manner synchronously in the transmission and the reception; (b) transmitting one of the segments in a reversed manner; and (c) upon reception, returning said reversed segment into the original direction.
Claim 3
Dependent Claim
32 words
A process according to claim 1 and the added steps of: reversing two segments at the time of transmission; and returning said two reversed segments into their original direction at their reception.
Claim 4
Dependent Claim
38 words
A process according to claims 1 or 2 and the added step of: adding to the pseudo-random definition of the dividing point between the segments the pseudo-random selection of at least one segment which is to be reversed.
Claim 5
Dependent Claim
70 words
A process according to one of the claims 1 or 2 and the added step of: selecting the dividing points between adjacent segments to be slightly overlapping in the neighborhood of the dividing point, so that the scrambled signal can be transmitted in a network with a limited frequency band, whereby signals may be transmitted in existing networks, regardless of the form of modulation and control in said existing network.
Claim 6
Dependent Claim
37 words
A process according to claim 4 and the added steps, upon reception, of: neglecting the front portion of the overlapping in the second segment when the at least one reversed segment is returned into its original direction.
Claim 7
Dependent Claim
25 words
A process according to one of the claims 1 or 2 and the added step of: scrambling both a luminance signal and a chrominance signal.
Claim 8
Dependent Claim
101 words
A process according to one of the claims 1 or 2 and the added steps of using: two sample memories, in a scrambling circuit, each of said sample memories having a capacity of one line of video signal, writing governing means for writing, in their natural order, the samples of each line of video signals to be scrambled, said memories being written into alternately; and governing means for reading the memories, said reading governing means alternately reading in at least a part of the samples stored in said memories, in an order which is the reverse of the order of input.
Claim 9
Dependent Claim
100 words
A process according to one of the claims 1 or 2 and the added steps of using: two memories for samples in an unscrambling circuit, each one of said memories having the capacity of one line of video signal; governing means for alternately reading the memories in an order which reads out the samples in their natural order; writing governing means for memorizing each line of video signals which has been scrambled, said writing governing means causing a reading of at least one part of the samples in an order which is the reverse of the order of their arrival.
Claim 10
Dependent Claim
20 words
A system constituted by a scrambling device according to claim 7 further comprising in the scrambling device a key generator.
Claim 11
Dependent Claim
32 words
The process of claim 9 and a key receiver means in the unscrambling device, said key receiver providing a pseudo-random sequence generator which ranks the samples between which said division takes place.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |