Auto-pedestal level clamp circuit
US4729026A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1986 |
| Grant date | Mar 1, 1988 |
| Priority date | — |
| Expiry date | May 20, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/18
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An auto-pedestal level clamp circuit, which clamps a pedestal level of a television signal input through a DC blocking capacitor using a pedestal level clamp switch to automatically adjust the pedestal level, includes a level detecting circuit for detecting a luminance signal level of the television signal, and an A/D converter for judging a luminance of a frame based on the output from the level detecting circuit. The level detecting circuit includes first and second gates, first and second switches controlled by the first and second gates, and a smoothing circuit. The pedestal level of the television signal input to the level detecting circuit through the pedestal level clamp switch is adjusted based on an integral potential level of the output from the A/D converter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.