Television – Image signal processing circuitry specific to television – Matrixing or mixing
Patent
1996-07-31
1998-01-13
Hsia, Sherrie
Television
Image signal processing circuitry specific to television
Matrixing or mixing
348660, H04N 967
Patent
active
057084815
ABSTRACT:
A color space converter is implemented using current mode analog circuitry to efficiently transform video data from a YC.sub.b C.sub.r format to an RGB format in order to allow the display of video signals on a color monitor. The analog current-mode circuitry is implemented in an integrated circuit that will operate at high clock rates and can be integrated in a small die area so as to reduce its cost. The color space converter includes Y, C.sub.b and C.sub.r current-mode conversion circuits to compute Y, C.sub.b and C.sub.r contributions to the G, R and B signals, and current-mode adders that add those contributions to the G, R and B signals to generate the G, R and B signals. Each conversion circuit includes (A) a respective folded cascode structure having an input coupled to a respective analog Y, C.sub.b or C.sub.r signal, each conversion circuit generating a respective Y, C.sub.b or C.sub.r current output; (B) at least one respective current mirror that generates from the Y, C.sub.b or C.sub.r current output an unadjusted Y, C.sub.b or C.sub.r contribution to at least one of the G, R and B signals, and (C) at least one current adder for subtracting respective offset currents from the unadjusted Y, C.sub.b or C.sub.r contribution to at least one of the G, R and B signals to provide the Y, C.sub.b or C.sub.r contribution to at least one of the G, R and B signals.
REFERENCES:
patent: 3996609 (1976-12-01), Avery
patent: 4300154 (1981-11-01), Engel
patent: 4346400 (1982-08-01), Hovens
Brooktree Corporation, Bt281 27 MHz Programmable Color Space Converter and Color Corrector (1993) Section 3, pp. 3-94 to 3-125.
CCIR International Radio Consultative Committee, Encoding Parameters of Digital Television For Studios, (Geneva, 1990) pp. 95-104.
Philips Semiconductors, Desktop Video Data Handbook (1995) pp. 74-75.
IEEE International Solid-State Circuits Conference, ISSCC96/Session 12/Serial Data Communications/Paper FP 12.1 (1996) pp. 194-195 and 443.
Bang-Sup Song, et al., NRZ Timing Recovery Technique for Band-Limited Channels (Feb. 1996) pp. 1-4 and Figures 1-7.
Tse Lawrence Tze-Leung
Yen King Cheung
Chrontel, Inc.
Hsia Sherrie
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