Automatic gain control device
US4963969A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Feb 23, 1989 |
| Grant date | Oct 16, 1990 |
| Priority date | — |
| Expiry date | Feb 23, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/52
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Disclosed is an automatic gain control device which comprises: a first amplitude detection circuit for detecting an average amplitude value of a television video signal, a peak amplitude value of the same television video signal, or a value obtained by mixing the average amplitude value and the peak amplitude value with a predetermined mixing ratio; a second amplitude detection circuit for detecting an amplitude value of a vertical or horizontal synchronizing signal in the television video signal; an amplitude control circuit for controlling an amplitude of an input television video signal; a synchronization circuit for detecting a vertical synchronizing signal and a horizontal synchronizing signal in the television video signal so as to generate various pulses including a clock pulse synchronized with the input television video signal by controlling an oscillation frequency of an oscillation circuit; and a synchronization phase lock detection circuit for detecting whether the synchronization circuit has been pulled into synchronism with the input television video signal, so that the amplitude control circuit is controlled by an output of the second amplitude detection circuit when…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.