Method and apparatus for reduced-bandwidth transmission of television signals
US5923374A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 8, 1996 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | Aug 8, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/127
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system for reducing bandwidth of video signals. Ordinarily, an NTSC (National Television Standards Committee) video signal has (a) a bandwidth of 6.0 MHz, (b) chrominance and luminance carriers separated by about 3.58 MHz, and (c) an audio carrier located at the upper end of the 6.0 MHz bandwidth. The invention reduces the separation between chrominance and luminance carriers to about 2.15 MHz, and decreases the bandwidth to about 4.0 MHz. In addition, the invention moves the audio carrier outside the 4.0-MHz bandwidth. The invention allows multiple channels, of 4.0 MHz bandwidth each, to be placed adjacent each other in a cable television spectrum, and the audio signals of the channels to be placed together, at the upper end of the spectrum, outside the range allocated to the video information. A larger number of channels is obtained than would otherwise be available, because the upper end of the spectrum is not suitable for carrying video information, but will handle audio information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.