Patent ID: 7834933
Filing Date: 2010-11-16
Classification: H04N

Abstract:
1. A vertical sync signal generator comprising: a vertical sync pulse detection circuit that detects a vertical sync pulse from an inputted video signal and outputs a detection signal; a first count circuit that counts a frame cycle of the vertical sync pulse from the detection signal and outputs a first count result; a first timing generating decoder circuit that decodes the first count result and generates a first timing signal for when the vertical sync pulse should be detected next; an accordance/discordance detection circuit that detects whether the detection signal and the first timing signal are in accordance and outputs a detection result of accordance/discordance; a second count circuit that, when the detection result is of accordance, loads the first count value and counts a frame cycle of the vertical sync pulse from the first count value with the loaded first count value acting as the initial value and outputs a second count value, and when the detection result is one of discordance, does not load the first count value and outputs the previously counted count value as the second count value; a second timing generating decoder circuit that decodes the second count result and generates a second timing signal for generation of a vertical sync signal; and a vertical sync signal generating circuit that uses the second timing signal and generates the vertical sync signal.