| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a corrected video signal with excellent guard performance without deteriorating gradation of a video signal. SOLUTION: A copy guard signal generating circuit 11 generates a pseudo synchronization pulse and an AGC(automatic gain control) pulse. A subtractor 13 subtracts a prescribed DC level from a pulse pair in a timing of the AGC pulse. Thus, a level of the AGC pulse is decreased more than a peak white level. An output of the subtractor 13 is superimposed onto digital image data by an adder 14 and converted into an analog signal by a D/A converter 16. Thus, even when the dynamic range of the D/A converter 16 is set to the peak white level, D/A conversion without distortion is attained. An adder 17 adds a DC level to an output of the D/A converter 16 and provides an output of the result. Since the peak level of the image is in matching with the dynamic range of the D/A converter 16, gradation of the image is not deteriorated.</p> |
