Digital signal broadcasting
US5787089A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1996 |
| Grant date | Jul 28, 1998 |
| Priority date | — |
| Expiry date | Jul 25, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2012/5687
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A distribution network groups television program signals into service tiers. To provide these from unsynchronized MPEG streams without resynchronization, each stream, representing a single program signal is encapsulated into ATM cells with a virtual path (VP) identification of each ATM cell corresponding to the service tier and a virtual channel (VC) identification corresponding to the respective program signal. Payloads in cells having the same VP are scrambled using a scrambling key allocated to that VP and hence to the corresponding service tier, and are unscrambled by entitled subscribers using the scrambling key which is supplied to them individually using public/private encryption techniques.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.