JPS645285A - Pal system demodulating circuit - Google Patents

Abstract

PURPOSE:To prevent the dislocation of the hue of a reproduced picture by providing a voltage controlled oscillator to output first and second sub-carriers, a phase switching circuit to supply the phase of the second sub-carrier to an R-Y demodulating circuit and a delay time to give the delay time to the first sub-carrier and to supply it to a B-Y demodulating circuit. CONSTITUTION:A voltage controlled oscillator VCO1a sets the mutual phase of first and second sub-carriers 11a and 11b to 90 deg. and outputs them. A phase switching circuit 2a inverts the phase of the second sub-carrier 11b by 180 deg. per one scanning line and supplies it to an R-Y demodulator 3a. A delaying circuit 4a gives a delay time suitable for the phase switching circuit 2a to the first sub-carrier 11a and supplies it to a B-Y demodulating circuit 5a. The phase between mutual the first and second sub-carriers 11a and 11b is adjusted to a prescribed value by a resistance 20 and a capacitor CE3. Thus, since a phase difference between mutual the first and second sub-carriers set by the VCO is held and supplied to the B-Y and R-Y demodulating circuits, a hue dislocation can be prevented.