GB773078A - Improvements in or relating to television systems - Google Patents

Abstract

773,078. Television. PHILIPS ELECTRICAL INDUSTRIES, Ltd. Oct. 6, 1954 [Oct. 8, 1953], No. 28790/54. Drawings to Specification. Class 40 (3). In a " compatible " colour television system successive lines are transmitted in one of three component colours and simultaneously therewith in alternate ones of the other two colours. As described, the " blue " signals of successive lines are transmitted with a band width of 200 to 300 kc/s. on an auxiliary carrier (and may be multiplexed with accompanying sound signals) and the " red " and " green " signals, which occupy a band width equal to that required for black/white reproduction, are transmitted alternately on a main carrier, each for the duration of a single line. At a colour receiver the " red " and " green " signals are supplied alternately to suitable colour imagereproducing devices (e.g. separate red and green colour tubes or a single dichromatic tube or to two " guns " of a tri-gun three-colour tube) and the " blue " signals to a separate " blue " colour tube (or to the third gun of the threecolour tube) the images being optically combined when separate tubes are employed and colour filters interposed in the optical paths if tubes producing monochromatic images are employed. At a black/white receiver (which is tuned to the frequency of the main carrier) the " red " and " green " signals are effective to produce a monochromatic image. The alternately transmitted signals may correspond to images of a " stereoscopicpair" or to different and unrelated pictures, the receivers in either case being suitably modified.