Signal-dependent chrominance subcarrier filtering circuit
US4149181A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 2, 1977 |
| Grant date | Apr 10, 1979 |
| Priority date | — |
| Expiry date | Sep 2, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/78
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and circuit for detecting and removing chrominance signal components from the luminance channel of a television receiver is shown. The luminance channel is separated into distinct subchannels, one of which has a filter providing attenuation at the chrominance subcarrier frequency. A detection circuit operates to select the output of the filtered subchannel whenever a chrominance subcarrier signal appears in the luminance channel. The detection circuit is sensitive to the phase relationship between the chrominance signal and a portion of the luminance signal and is therefore substantially immune to signals other than chrominance subcarriers, including high frequency components of the luminance signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.