Video signals clamping circuit for maintaining DC level of video signals
US5341218A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1992 |
| Grant date | Aug 23, 1994 |
| Priority date | — |
| Expiry date | Apr 7, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/185
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A video signal clamping circuit capable of maintaining a DC level of a digital video signal at a fixed level, in which a pedestal level in a vertical blanking period of the digital video signal after an A/D conversion is sampled, and an average value of a plurality of sampling data in a plurality of fields is calculated by an average value calculator. The average value is compared with a predetermined clamp level reference value by a comparison output circuit, and depending on the comparison result, a signal either added or subtracted by a certain width to or from an output signal of a predetermined period before is output for automatically controlling a clamp voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.