Video scrambling by the application of a variable periodic scrambling waveform
US4568974A · kind A · utility
10Cited by
4References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1982 |
| Grant date | Feb 4, 1986 |
| Priority date | — |
| Expiry date | Oct 28, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/171
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A means for scrambling video signals by the application of a periodic scrambling waveform which has the effect of altering the normal amplitude relationship between horizontal sync and the video picture portion of a horizontal line uses the comparison between the brightness level of the video signal during a predetermined time period with a reference as a means for varying the amplitude of the periodic scrambling waveform.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.