| 摘要 |
PURPOSE:To project pictures of good quality by providing an automatic phase shift control (APC) circuit which is used to eliminate the time base fluctuating component of a chrominance signal, a reference oscillator, and a means which divides the frequency of the output of the reference oscillator to generate a reference horizontal frequency signal and using the output of the reference oscillator as a reference signal for time base correction of a luminance signal. CONSTITUTION:The output of a reference oscillator 25 is divided or multiplied in terms of frequency to generate a horizontal reference signal Ha having the same frequency as the horizontal frequency. Meanwhile, the luminance signal from a clamping circuit 35 is supplied to a synchronizing signal separating circuit 44, and a horizontal synchronizing signal Hb is extracted in this circuit 44. This horizontal synchronizing signal Hb is inputted to a phase comparator 43 through a half killer circuit 45. Said horizontal reference signal Ha is inputted to the phase comparator 43 also. The phase of the signal Ha and that of the horizontal synchronizing signal Hb are compared with each other to obtain an error signal YEr. If this error signal TEr is used to correct the time base of the luminance signal, a reproduced luminance signal has the phase based on the reference signal of the APC circuit and phase relations to the chrominance signal are kept prescribed.
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