VIDEO SIGNAL PROCESSOR EMPLOYING EDGE REPLACEMENT, PRESHOOTS AND OVERSHOOTS FOR TRANSIENT ENHANCEMENT

摘要

A video input signal (IN) is applied to a delay circuit (22)having a plurality of taps (a;b;c;d;e) which are coupled to maximum(40) and minimum (50) value selection circuits. In the absence of avideo signal transient, the center tap (C) of the delay circuit iscoupled to an output terminal (OUT) via an output switch (60). Whena "white going" transient occurs, the output switch sequentiallyselects the outputs of the minimum and maximum value selectors forapplication to the output terminal. When a "black going" transientoccurs, the output switch sequentially selects the outputs of themaximum and minimum value selectors for application to the outputterminal. Offset producing circuits (42;52) are coupled to theminimum and maximum value selectors whereby an output signal isproduced having a preshoot, an overshoot and a rapid transitiontherebetween for video input signal transients of either direction andin which the shoot amplitudes are independently controllablethereby providing the combined transition speed advantages of"edge replacement" enhancement systems with pre-shoots and over-shoots characteristic of transversal peaking systems.