| 摘要 |
PROBLEM TO BE SOLVED: To make a 4 fsc frequency clock circuit for a YC separation unnecessary by providing only the clock circuit of a reference frequency (27 MHz) as an analog clock circuit in a composite analog/component digital image signal converter. SOLUTION: Generated from a synchronizing signal extracted from an input analog signal is 27 MHz clock used as the reference of the component digital image signal. The input signa is A/D converted by this clock. The subcarrier signal synchronized with the burst signal of the composite image signal is generated from the clock and the A/D converted digital video signal only by a digital circuit. The YC separation of the composite image signal is performed by this subcarrier signal to a component image signal. Further, a burst AGC circuit is added in which the amplitude of the burst signal of the input image signal becomes constant. Consequently, the stable subcarrier signal can be extracted, and the accuracy of the YC separation is improved. COPYRIGHT: (C)2005,JPO&NCIPI
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