ON-VEHICLE SYNCHRONIZATION SIGNAL PROCESSING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To solve the problem wherein a packaging area and cost of a printed circuit board are adversely affected because a dedicated synchronization IC is provided differently from a video processing LSI and because stable synchronization separation cannot be performed from a video signal at the time of receiving a radio wave of an on-vehicle television, and also the problem wherein video jitters may occur when a video is displayed on a high-resolution panel because of a lack of detection accuracy of phase difference calculation between external synchronization and internal synchronization. SOLUTION: This synchronization separating circuit is provided with: a filter processing means; a regular lower end value correction processing means of video signal data to be inputted; and a lower end value detection processing means for providing a detection margin to the lower end value detection. The circuit is configured so that the phase difference data is calculated by detecting phase difference between both the signals, i.e. a TTL type synchronization signal and digital data type synchronization signal which correspond to an on-vehicle environment where an electric field easily changes and are derived by the synchronization separating circuit, and a phase difference reference signal to be transmitted from an internal count-down horizontal processing circuit. COPYRIGHT: (C)2005,JPO&NCIPI