GB787806A - Improvements in or relating to colour television - Google Patents

Abstract

787,806. Television. ELECTRIC & MUSICAL-INDUSTRIES, Ltd. Oct. 17, 1955 [Oct. 15, 1954], No. 29711/54. Class 40 (3). Frame sequential colour signals R + G + B are directed into separate channels by a gate 10 and displayed on cathode-ray tubes 1, 2 and 3 from which simultaneous colour signals are derived by storage-type pick-up tubes 7, 8, 9, the system being characterized by the use of low- and high-pass filter combinations 11 and 14 whereby only the low-frequency components RL and BL of the red and blue signals pass to tubes 2 and 3 whilst the high-frequency components RH and BH pass to gate 13 where they are added to the complete green signal G and applied to tube 1. 12 and 15 are amplifiers. 28 is a delay network introducing a delay equal to that introduced by the low-pass filters in filter combinations 11 and 14. The derived simultaneous signals may be utilized in any way; the Figure illustrates a low- and high-pass filter combination 16 to separate the green low-frequency components GL from the combined red, green and blue high-frequency signals MH in the output of pick-up tube 7 and an adder 18 and matrix network 17 for deriving a luminance signal EYL + MH together with either colour difference signals RL-EYL and BL-EYL or I and Q signals in accordance with American N.T.S.C. standards. The number of combinations of cathode-ray display and pick-up tubes may be reduced to one or two by the employment of the arrangements described in Specifications 778,180 and 778,181. The Specification describes a circuit, Fig. 2 (not shown), for the filter combinations 11, 14 and 18. Specification 778,179 also is referred to.