| 摘要 |
<p>PURPOSE:To automatically obtain a sampling clock synchronizing with several types of dot clocks by automatically detecting a horizontal frequency and a vertical frequency and automatically generating the sampling clock. CONSTITUTION:The horizontal frequency and the vertical frequency of a video signal are detected by a horizontal frequency detecting part 101 and a vertical frequency detecting part 102. A sampling clock generating part 103 generates the sampling clock for quantizing to video signal. The frequency dividing ratio of a frequency divider 104 is changed by the detected horizontal frequency and the vertical frequency to divide the frequency of the sampling clock and have a frequency equal to the horizontal frequency. The signal of the frequency equal to this horizontal frequency is fed back to the sampling clock generating part 103. In the sampling clock generating part 103, the sampling clock is synchronized with the dot clock by the signal and of the frequency equal to this horizontal frequency and the horizontal frequency.</p> |
