Apparatus and method for using forward error correction setting to enable simultaneous use of multiple modulation systems on terrestrial distribution networks
US5923642A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 11, 1997 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | Jul 11, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method using the forward error correction setting to enable simultaneous use of multiple modulation systems on terrestrial distribution networks including cable television systems is described. The system includes a transcoder having a demultiplexer for demultiplexing a forward-error-correction decoded signal into a main data stream with a bit rate suitable for 64-QAM cable transmission and an auxiliary data stream with a bit rate approximately half that of the main data stream. Two of such auxiliary data streams can be combined to generate an output data stream with a bit rate suitable for 64-QAM cable transmission. The system also includes a satellite transmitter which can adjust its convolution coding rate to either 1/2 or 3/4 for 64-QAM and 256-QAM cable channels respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.