JPH0632457B

PURPOSE:To represent the gradation of a still picture with a simple constitution by constituting a pseudo neutral color generating means of a clock pulse superimposing means, a matrix circuit for adding a clock pulse superimposing luminance signal and a color difference signal and an A/D converting circuit for binarizing an added output signal. CONSTITUTION:The pseudo neutral color generating means 4 includes a direct current checking capacitor C and a transistor TR2 in which a luminance signal Y is applied to a base and the clock pulse from a clock pulse generating means 1 is applied to an emitter and is constituted of the clock pulse superimposing means 5 for outputting a signal (d) obtained by superimposing the clock pulse on the luminance signal Y from a collector, the matrix circuits 6a-6c for adding and outputting the superimposing luminance signal (d) and the color difference signals B-Y, R-Y, G-Y and the A/D converting circuits 7a-7c for binarizing the added output signal. Respective chrominance signals stored in respective memories 8a-8c are transmitted through D/A converting circuits 9a-9c.