Contour correction circuit

Abstract

Abstract PURPOSE:To obtain a sharp picture without intrusion of a black thin line to a black contour by not applying contour correction by scanning speed modulation to a low brightness part of a luminance signal but applying it only to a high brightness part. CONSTITUTION:A limiter circuit 5 clips a low brightness part because a diode D is put on when an inputted negative polarity luminance signal Y reaches a prescribed level or over. The signal is differentiated by a 1st order differentiating circuit 6, supplies the result to a speed modulation coil 8 to apply the horizontal deflection, then the speed of the low luminance component of the 1st half of the leading part and the latter half of the trailing part of the luminance signal is not quickened and no speed modulation is implemented. Thus, no contour correction by the speed modulation is applied to the 1st half of the leading part and the latter half of the trailing part of the low luminance signal on the screen but applies to the latter half of the leading and the first half of the trailing part of the high luminance signal. Then clear picture quality without intrusion of a black thin line to the contour of the black level is obtained.

Inventors

• 👤 Hiroshi Yoshida
• 👤 宏 吉田
• 👤 Shunji Asai
• 👤 俊次 浅井
• 👤 Hirohisa Kitagishi
• 👤 広久 北岸

Bibliographic Details