TV Receiver circuitry for performing chroma gain, auto-flesh control and the matrixing of I and Q signals to (R-Y), (B-Y) and (G-Y) signals
US4523221A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1983 |
| Grant date | Jun 11, 1985 |
| Priority date | — |
| Expiry date | Jun 7, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/67
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A color TV receiver designed to digitally process I and Q color mixture signals incorporates chroma gain control, static tint control and autoflesh in the circuitry for converting the I and Q signals to (R-Y), (B-Y) and (G-Y) for R,G,B matrixing. The magnitude and angle of the vector sum of I and Q are first determined. The angles are then adjusted for static tint control and then applied to a ROM which is programmed to output angles adjusted for fleshtones. Angles from the autoflesh ROM are applied to a summing circuit which algebraically adds to the flesh corrected angle, angle values corresponding to the angular displacement between the I axes and the (R-Y), (B-Y) and (G-Y) axes. The angles produced by the summing circuit are applied to a look-up ROM which produces the cosine values of the applied angles. The magnitude signal is amplified by coefficients which relate the I and Q signals to (R-Y), (B-Y) and (G-Y) components and which coefficients may be amplified by a chroma gain signal. The amplified magnitude signal is thereafter multiplied by the cosine values which effectively projects the vector sum or chrominance signal onto the respective (R-Y), (B-Y) and (G-Y) axes to gen…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.