COLOUR TELEVISION COMPOSITE SIGNAL DIGITAL DECODER, PARTICULARLY MULTISTANDARD DIGITAL DECODER

摘要

The colour television composite signal digital decoder, comprising luminance information transmitted on a carrier and chrominance information transmitted on a sub-carrier, comprises an analog/digital (A/D) converter (1) of which the input receives the composite signal (CVBS) and of which the output is connected in parallel to a luminance channel (2) and to a chrominance channel (3); the luminance channel comprises a trap filter (4) whereas the chrominance channel comprises at least one band-pass filter (8). The luminance channel (2) further comprises a vertical medial filter assembly (6) intended to compare the luminance signals of three successive TV image lines and to output the median value of said signals, whereby the chrominance diaphoty ("cross-luminance") is substantially reduced and the strong vertical transitions of luminance are preserved.