Sanyo Electric Co., Ltd.

Hidehiro Ugaki

Nobukazu Hosoya

Yoshichika Hirao

Kazunori Nohara

A Y/C separation circuit includes a glass delay line for delaying an input composite video signal. A luminance signal and a chrominance signal are separated from each other by an adding circuit and a subtracting circuit each of which receives the input signal and an output signal from the glass delay line. The output signal from the glass delay line is phase-shifted by a 90.degree. phase shifting circuit and then inputted to a multiplier which further receives the input signal. The multiplier outputs an error signal according to a phase difference between color burst signals included in the both signals, and a control voltage according to the error signal is outputted from a low-pass filter. The control voltage is applied to gyrators which terminate an input and an output of the glass delay line, respectively, whereby an inductance value of each of the gyrators is controlled by the control voltage such that a delay time of the glass delay line can be exactly adjusted at one horizontal period.

Comb filter-type Y/C separator circuit

A frequency of a chrominance signal including a jitter component and separated from a color video signal is converted from a first frequency to a second frequency by first frequency converting device. Then, the chrominance signal which frequency is converted to the second frequency is converted to have the original frequency by second frequency converting device. Each of the first frequency converting device and the second frequency converting device includes a multiplier and a bandpass filter. One multiplier of the first and the second frequency converting devices and receives a frequency signal corresponding to a phase difference between a reference frequency signal and a color burst signal separated from the chrominance signal. As a result, the jitter component is removed from the chrominance signal either in the first or the second frequency converting. In the first and the second frequency converting devices and, the input signal and the output signal so widely differ from each other in frequency that the respective frequency components included in the output signal of the multipliers in the respective frequency converting device expend widely along an axis of a frequency. As a result, the bandpass filter in each frequency converting device is enabled to easily extract only a signal of a desired frequency component.

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Daito, Japan

Hidehiro Ugaki