PICTUREEQUALITY IMPROVING DEVICE OF COLOR TELEVISION RECEIVER

摘要

PURPOSE:To improve the resolution of a colored picture part by positively mixing the high frequency component of a luminance signal into a color difference signal according to the intensity of the color difference signal. CONSTITUTION:Color difference signal C-Y is inputted from coloring signal source 11 to differentiating circuit 19 for differentiation. Luminance signal Y, on the other hand, is applied to and differentiated by differentiating circuit 20 as well. Differential outputs of differentiating circuits 19 and 20 are inputted to multiplier 21 to output their product. The polarity of its output is positive when transient parts of luminance signal Y and color difference signal C-Y rise or fall in the same direction or negative when in the opposite direction. The circuit method like this, when the luminance signal and color difference signal differ in transient polarity, reduces the amplitude or inverts the polarity of high frequency component YH of the luminance signal applied to variable gain amplifier 17.