| 摘要 |
PROBLEM TO BE SOLVED: To realize an inexpensive moire correction circuit capable of performing such a moire correction that a moving amount of a picture pattern in the horizontal position isn't changed by horizontal frequency. SOLUTION: This circuit is constituted of a frequency discriminator 4 detecting the horizontal frequency (f) from a horizontal synchronizing signal S0 in the input image data and generating a DC voltage Vf according to that, a synchronizing signal shaping part 5 providing a rise time Tr answering to the DC voltage Vf and waveform shaping the horizontal synchronizing signal S0 , a correction waveform generation part 3 controlling a pulse height value of a rectangular wave generated at the frequency of 1/2 of the horizontal frequency according to a prescribed adjustment signal K and a synchronous phase correction part 6 controlling a phase difference for a period until the waveform shaped horizontal synchronizing signal S2 arrives at the pulse height value and sending out the phase controlled horizontal synchronizing signal S3 to a horizontal deflection circuit 7. When the horizontal frequency (f) becomes high, the deviation valueϕof the phase of the horizontal synchronizing signal becomes large, and both are canceled, and the moving amount of the horizontal position isn't changed by the change of the horizontal frequency.
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