| 摘要 |
PURPOSE:To reproduce and deliver a color video signal of an SECAN system of a high quality with a simple circuit constitution, by processing a synthetic color signal reproduced out of a recording medium with a jitter and accordingly reducing the phase shift to completely eliminate the jitter. CONSTITUTION:A synthetic color video signal containing a jitter which is reproduced out of a recording medium is supplied to an input terminal 1. This video signal is applied to a delaying circuit 10 and a frequency converter 11, and the frequency of the signal is converted by the difference to a prescribed frequency. Thus the phase shift is reduced for a carrier chrominance signal supplied from a subtracter circuit 13 forming a comb-shaped filter. The output of the circuit 13 is supplied to an automatic phase control circuit 24, a demodulating circuit 28, etc., and a demodulating color subcarrier which is synchronous with the color burst signal in the carrier chrominance signal with elimination of the phase shift caused by the jitter is delivered from the circuit 24 to be applied to a switch circuit 27. Then the subcarrier waves having the phases different of each other by 90 deg. are applied to the circuit 28 with every 1H. Thus the fluctuation of the hue due to the jitter can be completely eliminated. In such way, a color video signal of an SECAN system is obtained with high quality through a simple constitution. |
