| 摘要 |
<p>PURPOSE:To perform accurate quantization with an excellent followup capability to a video signal, by providing a peak tracking and holding circuit which tracks the peak value of a video signal to a black output and a resistance voltage divider for a floating slice level. CONSTITUTION:A slice level set by the 1st black level is used for a next bit; when the video signal of this next bit is higher than the slice level, a comparator 7 generates an L-level output to turns on an analog switch 13 when a clock signal CLK is at the level L, and a new slice level is generated and used for a next bit. When the video signal is lower than the slice level, on the other hand, the comparator 7 generates an H-level output and a capacitor C1 holds the last value; and the slice level decreases depending on the time constant determined by the capacitor C1 and a resistance R4.</p> |
