JPS5762685A - Signal generator in color television system - Google Patents

Abstract

PURPOSE:To improve the quality of reproduced picture on screen remarkably without changing the system and circuit of a receiver, by synthesizing a color difference signal from a signal arbitrarily cnverting the primary color signal corresponding to the original picture. CONSTITUTION:Primary color signals R, G, B are applied to shift registers 23-25 for delay, they are converted at a logical converter 26 and are outputted as RM, GM, BM respectively. The output signals are applied to a matrix circuit 33 and modified color difference signals with broad band are formed through addition/subtraction, they are modified color difference signals with narrow band which are filtered for the low frequencies at LPF34-36. After they are squared at multipliers 37-39 and added at a matrix circuit 40, they are applied to a subtractor 31. On the other hand, signals R, G, B are delayed at delay lines 41-43 and squared at multipliers 27-29, then they are added at the matrix circuit 30, applied to the subtractor 31, where the sum of square of the modified color difference signal of narrow band is subtracted, the resultant is applied to a non-linear circuit 32 to obtain the luminance signal with high quality.