Synchronizing signal detection circuit

摘要

The present invention provides a synchronizing signal detection circuit capable of always stably detecting a synchronizing signal. The synchronizing signal detection circuit predicts detection positions of synchronizing pulses every synchronization cycle peculiar to an input video signal. The synchronizing signal detection circuit further supplies the input video signal to a plurality of unnecessary signal eliminating paths in common and extracts synchronizing signals of every path respectively from video signals of every path obtained by eliminating unnecessary signals according to the characteristics of the paths every path. Then, the synchronizing signal detection circuit acquires detection positions of synchronizing pulses of the synchronizing signals of every path, selects a synchronizing signal of every path at which a difference in time between each of the detection positions of every path and the predicted detection position is minimal, and sets the selected synchronizing signal as an output synchronizing signal.