| 摘要 |
PURPOSE:To attain the picture quality control with a simple hardware constitution, by adding an original video signal multiplied by a coefficient to be controlled to a higher harmonic component extracted from the video signal at a digital filter of linear phase. CONSTITUTION:The characteristic of Equation II of a digital filter to be used satisfies Equation I . An adder 2 performs the operation of (Z<-8>+1) in Equation IIand -(1/2) is multiplied by the (Z<-8>+1) at a multiplier 3 and the result is inputted to an adder 4. A signal delayed by 5-stage from the input is inputted to another input of the adder 4 and this is used for the time matching of one-stage delay between the multiplier 3 and the adder 4. The output of the adder 4 is multiplied by 1/2 at the multiplier 5 to constitute a filter of equation II. The group delay characteristic is a constant by using the filter satisfying equation I , and natural picture quality control is attained without giving unnatural overshoot and pre-shoot to the picture quality. |
