Method and apparatus for communication of video, audio, teletext, and data to groups of decoders in a communication system
US4866770A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 14, 1986 |
| Grant date | Sep 12, 1989 |
| Priority date | — |
| Expiry date | Aug 14, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/4882
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A communication system enabling transmission of individual subscriber teletext messages, audio and video to individual subscribers and permitting group communications of audio, video, teletext and data information from a single central subscriber location, such as a corporate head office to a plurality of satellite offices, such as field or sales offices of the corporation, is disclosed. A composite signal including the information to be transmitted as well as system wide, individual decoder and group decoder control signals is transmitted. The system-wide control signals include data germane to operation of each of the decoders of this system, including key information needed to decode the composite signal. The system-wide control data is transmitted at a first relatively high frequency. The group decoder information includes information permitting individual groups of decoders to receive information portion of the composite signal being transmitted at a given time. In this way, for example, an audio and video signal can be transmitted at a convenient time from a central location to a number of satellite locations. The group decoder control signal can also include signals used by …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.