| 摘要 |
PURPOSE:To improve the acquisition characteristic of synchronism of an APC device by switching a second phase difference signal to a signal in which a code is equal to the second phase difference signal and the size is a suitable value when the APC device is dislocated from a synchronizing condition and the level of a first phase difference signal exceeds the prescribed value. CONSTITUTION:A carrier chrominance signal inputted from a terminal 51 is demodulated to first and second demodulating chrominance signals with first and second demodulators composed of multipliers 52 and 53 and LPFs 54 and 55. Burst gate circuits 56 and 57 remove first and second phase difference signals corresponding to the burst signal from the first and second demodulating chrominance signals. A phase error detecting device 58 operates the phase error between the burst signal and the signal for demodulation from these and a phase error signal is obtained. The phase error signal is converted to the phase signal, and converted to the signal for demodulation of the first and second demodulators by an SIN converter 63 a COS converter 64. A modulator composed of multipliers 65 and 66 and a subtracter 67 modulates the first and second demodulating chrominance signals, the carrier chrominance signal is obtained and outputted from a terminal 72.
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