TV signal transmission systems and methods
US5040063A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1989 |
| Grant date | Aug 13, 1991 |
| Priority date | — |
| Expiry date | Oct 23, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/186
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A hybrid television signal of less transmission power or better signal to noise performance is made up by removing low frequency analog components from the video signal, digitizing them and sending them as data in non-active video portions of the transmitted signal. A two step hybridization process, with the first step removing the line averaged value of the video components of the video signal and the second step removing the remainder of the video components under 200 KHz, is described. Temporal filtering, signal pre-emphasis, compression, time dispersion and double sideband suppressed carrier modulation about a centered carrier are disclosed for reducing peak signal amplitudes and for minimizing co-channel interference to and from NTSC signals. Time dispersion is done horizontally, vertically or both to reduce the peak signal amplitudes. Time dispersion in conjunction with low frequency removal and temporal filtering is preferred. Time dispersing lower frequencies more than higher frequencies contributes to an optimized video display. The hybrid signal system is uniquely adapted to a high definition television signal in a limited frequency channel with an NTSC signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.