Automatic color level control system with threshold tracking
US4106055A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 5, 1977 |
| Grant date | Aug 8, 1978 |
| Priority date | — |
| Expiry date | Jul 5, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/68
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A DC controlled amplifier is used to control the chrominance gain, and hence the color saturation, of a television receiver. The voltage on the wiper of a Color Control variable resistor and the output of an Automatic Color Level (ACL) detector are combined in a summing network to provide a DC voltage to the controlled amplifier. The ACL detector develops an output voltage that tends to maintain the peak-to-peak chrominance signal, and therefore the color saturation, at or below a threshold level. A control tracking circuit varies the threshold level in accordance with the voltage on the wiper of the color control variable resistor, thereby maintaining the dynamic range of the Automatic Color Level Control System relatively independent of the setting of the Color Control.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.