Title:
VIDEO SIGNAL NONLINEAR CONTROL CIRCUIT
Document Type and Number:
Japanese Patent JPH02260875
Kind Code:
A
Abstract:
PURPOSE:To increase the gradation of a black level and a white level in response to the content of a brightness level in a video signal input by providing a bias voltage control circuit section, a nonlinear control circuit section and an output circuit section. CONSTITUTION:A video signal input is detected by a bias voltage control circuit section 50, which outputs a bias voltage in response tot eh brightness level of the video signal input to a black level nonlinear control circuit 10 and a white level nonlinear control circuit 20 in a nonlinear control circuit section 30. The video signal input including much of black level vicinity component, for example, is expanded for its black level by the black level nonlinear control circuit 10 and an output circuit section 40 shapes the waveform and amplifies the level, resulting that the video signal is outputted. Similarly, the video signal input including much of white level vicinity component is expanded for its white level by the white level nonlinear control circuit 20 and the video signal is outputted from the output circuit section 40. Thus, the change in the gradation is increased in the vicinity of black level and white level in response to the content of the brightness level in the video signal input.
Inventors:
FUKUSHIMA YASUMASA
Application Number:
JP8171289A
Publication Date:
October 23, 1990
Filing Date:
March 31, 1989
Export Citation:
Assignee:
SHARP KK
International Classes:
H04N5/20; H03G11/08; (IPC1-7): H03G11/08; H04N5/20
Attorney, Agent or Firm:
Kenzo Hara