| 摘要 |
PURPOSE:To realize the reproduction for the excellent video signal, by securing the fixed phase for the carrier chrominance signal which is reproduced by means of the phase comparator circuit, the voltage control oscillator circuit and others. CONSTITUTION:Tracking control signal f1 is the continuous signal with the high frequency and thus always compared with the oscillation output of reference oscillator circuit 27 at phase comparator circuit 26. And accordingly the oscillation frequency of voltage control oscillator circuit 33 is also controlled at all times in accordance with the output signal proportional to the phase difference of both signals which are led to the output end of circuit 26. As a result, the control is always be given to the modulating carrier to be applied to modulator circuit 32, and thus the carrier chrominance signal with the constant fixed phase is led to the output end of circuit 32. Accordingly, no color shading is caused to the reproduced picture for the vertical period with no color distortion caused even for the horizontal period. Thus the excellent video signal can be reproduced. |
