VIDEO AMPLIFIER CIRCUIT

• Main Author: SEKO KAZUYUKI
• Format: Patent
• Language: English
• Published: 13.06.1990
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION

PURPOSE:To correct difference of luminance between the center part and the peripheral part of the picture of a CRT by generating and synthesizing the vertical and horizontal parabolic waves of specific waveform, and setting an amplification degree for a video signal at the lowest level at the intermediate of each scanning period by a synthesized wave. CONSTITUTION:A vertical parabolic wave formation circuit 2 which generates the vertical parabolic wave V1 of parabolic waveform projecting downward being set at the lowest level at the intermediate of each vertical scanning period at every vertical scan by the output signal of a vertical output circuit 1, a horizontal parabolic wave formation circuit 4 which generates the horizontal parabolic wave V2 of parabolic waveform projecting downward being set at the lowest level at the intermediate of each horizontal scanning period at every horizontal scan by the output signal of a horizontal output circuit 3, and a synthesis circuit 5 which synthesizes those output signals V1 and V2 are provided. And control to set the amplification degree for the video signal so as to be set at the lowest level at the intermediate of each vertical and horizontal scanning period according to the output signal of the synthesis circuit 5 is performed. In such a way, it is possible to obtain the same luminance at the entire picture of the CRT.