JPS6245756B

PURPOSE:To keep a chroma level in a digial signal of an output of an analog- digital converter to a constant value, by adding a required minimum circuit to a clock generating circuit synchronized with a burst signal. CONSTITUTION:An output digital signal of an analog-digital converter 15 is inputted to a Y-C separating circuit 16 in a digital signal processing and the signal is separated into a luminance signal Y and a color signal C. The separated signal C is controlled at a gain control circuit 17 so that the gain is increased when a signal At is small based on a burst peak value signal At and the gain is small when the signal At is large. Thus, an output color signal C' of the circuit 17 is kept to a constant value at all times.