| 摘要 |
<p>PURPOSE:To execute an exact blanking processing by providing a circuit to switch a Y signal to a constant value, which is smaller than a pedestal level, in correspondence to a signal to show a blanking period and integrating the value of data, which show the blanking period, into picture data. CONSTITUTION:A video input signal 1 is converted to the PCM data of 8 bits, for example, by an A/D 2. In a blanking period generator 11, a blanking(BLK) control signal 14 to be synchronized to the video input and to express the blanking period is obtained from vertical phase information 12 and a clock 13. A selector 7 is operated by the BLK control signal 14 and the BLK data from a BLK data generator 8 are padded into the Y signal after being black- clipped. Here, the BLK data are obtained as a 3B (16-ary). Since there is no value of <3C for the Y signal by a black clip 6, the period of the value 3B can be easily and securely detected with the blanking period.</p> |
