High-definition television system.

摘要

For a compatible color television system suitable for high and low definition on display, a MAC-system is taken as an example. Herein use is made of a digitally assisted DATV. To effect a bandwidth reduction encoding and bandwidth reduction decoding, use is made, in addition to the MAC-coding and MAC-decoding, of at least three picture signal channels (PC) each having a different picture signal refresh period equal to, for example, 80, 40 and 20 ms which are coupled via a time-division multiplex circuit (MUX). For with the diversity of picture signal sources, it was found that distinguishing during the picture signal processing between a film mode (SW1, T40) and a non-film mode (SW1, T20) results in a significantly improved high-definition picture resolution. This distinction is expressed at the DATV by one information bit (FM min ). During the non-film mode (SW1, T20) three Y-luminance channels (PC11, PC13 and PC12) of 80, 40 and 20 ms and two U and V-chrominance channels (PC21 and PC22) of 80 and 20 ms are operative. During the film mode (SW11, T40) the Y-channels (PC11 and PC13) and the U and V-channels (PC21 and PC23) of 80 and 40 ms are only operative.