| 摘要 |
PROBLEM TO BE SOLVED: To provide a means for preventing chatering due to jitters in selecting a memory on a reading side to avoid address passing when both frequencies are close each other in a circuit to synchronize an input video signal with a synchronous signal, on a display side, to be a reference. SOLUTION: When selecting a reading memory area, an area 1 pulse with a prescribed width by setting a vertical pulse W from a writing address generating part 10 as a start point, and an area 2 pulse with a prescribed width corresponding the maximum jitter amount from an ending point of the area 1 pulse are generated. When a vertical pulse R from a reading address generating part 18 is present within the area 1 pulse, the reading memory area anterio by 1 field from the current writing memory area is selected to be read out, when the vertical pulse R is present within the area 2 pulse, the memory area same as the previous memory area is sequentially selected to be read out. Otherwise, the current writing memory area is selected to be read out. COPYRIGHT: (C)2004,JPO
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