Method and apparatus for television signal scrambling using a line expansion technique
US5606612A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1994 |
| Grant date | Feb 25, 1997 |
| Priority date | — |
| Expiry date | Jul 25, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/1675
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for scrambling an original analog video signal samples predetermined portions of the original video signal at a first rate and stores the sampled portions of the original video signal within a memory device. The stored video signal is read out of the memory device at a second rate, which is less than the first rate, to produce a time expanded scrambled video signal. A predetermined code is inserted into the time expanded scrambled video signal which is then converted into an analog scrambled video signal and transmitted through a channel. A method and apparatus for descrambling the scrambled video signal to produce a reconstructed video signal samples the scrambled video signal at the second rate, stores the sampled scrambled video signal into a memory and reads the sampled scrambled video signal out of the memory at the first rate. Replicas of the eliminated portions of the original video signal are reinserted into the sampled video signal to produce a digital version of the original video signal which is then converted to analog to produce the reconstructed video signal. The code word within the scrambled video signal is used to align each frame of the reco…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.