Apparatus for encoding and decoding information
US4527195A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 11, 1982 |
| Grant date | Jul 2, 1985 |
| Priority date | — |
| Expiry date | Jun 11, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/167
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus for encoding and decoding information. Multiple scrambling techniques are provided to prevent unauthorized reception of a television picture signal. A first mode of scrambling provides for shifting randomly occurring horizontal synchronization pulses within each field of video signal producing horizontal as well as vertical instability. Video line inversion of selected lines within a field comprises a second mode of scrambling of the signal. A third mode of scrambling provides for amplitude shifting the television signal during selected portions of the signal which contains luminance and chrominance information following a line synchronization pulse.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.