| 摘要 |
PROBLEM TO BE SOLVED: To realize a synchronization processing unit and its processing method where the position of a horizontal synchronizing signal is accurately detected even when the amplitude of a video signal or the like with bad linearity is fluctuated. SOLUTION: A video signal is delayed by a prescribed period L1 by loading a counter in response to a start pulse whose start point is a trailing of a Hsync to detect a 0IRE (0%) level of the input video signal for a detection period range W1. Similarly, the signal is delayed by a prescribed period L2 to detect a 40IRE (100%) level of the input video signal for a detection period range W2. A 50% level is calculated from them by an arithmetic operation. Furthermore, the video signal is delayed by a prescribed period L3 to detect a 50% point of a trailing edge of tail end of a signal B1 for a detection period range W3 and a calculated 50% level is used for a cross point of the 50% point of the tail end trailing edge of the signal B1 to obtain a horizontal synchronizing position pulse (A). Thus, the horizontal synchronizing position is stably detected. |
