| 摘要 |
PROBLEM TO BE SOLVED: To provide a vertical deflection circuit, a synchronization and a screen display device in which a size in a vertical direction of an image of a video signal is kept constant independently of a period of a vertical synchronizing signal so as not to cause overlapping of horizontal scanning lines and uneven horizontal scanning lines. SOLUTION: This vertical deflection circuit drives a vertical deflection coil L1 so as to keep a size in a vertical direction of an image of a video signal constant independently of a period of a vertical synchronizing signal A and is provided with a count means 10 counting a horizontal synchronizing signal B, a comparison means 12 comparing a count when the count means 10 is reset with a prescribed count, a voltage output means 13 outputting a voltage depending on the result of comparison by the comparison means 12, and a D/A converter circuit 11 converts the count of the count means 10 into a voltage and outputting a voltage outputted from the voltage output means 13 as a reference voltage and the vertical deflection coil L1 is driven based on the voltage outputted from the D/A converter circuit 11. |
