| 摘要 |
PURPOSE:To reduce a color shade immediately after switching a head, by switching the head by a color signal which is not delayed, and thereafter, using a phase comparing output at the time when a delay time elapses and a phase of a demodulated output has become stable, as a control signal of a variable frequency generator of a delayed color signal. CONSTITUTION:A value of a difference output of an output of a LPF 16 and an output of a LPF 24 at the time point when the polarity of a signal which has passed through a delaying circuit 28 having a delay quantity equal to a delaying circuit 18, from a head switch pulse input 27 has been inverted is held until the polarity of the signal is inverted in the next time, and the sum with the output of the LPF 24 is outputted. This output becomes an output frequency control signal of a variable frequency generator 26 of demodulation reference signal of a demodulator 19. Subsequently, by delaying a digitized color signal by a time portion until a phase of a demodulated output becomes stable, after switching a head by a color signal which is not delayed, a phase comparing output at the time when a delay time elapses and a phase of the demodulated output has become stable is used as a control signal of the variable frequency generator of a delayed color signal. In such a way, a color shade immediately after switching the head is reduced.
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