| 摘要 |
PROBLEM TO BE SOLVED: To prevent the fidelity of the color tone of a reproduced image from deteriorating due to the uneven gain control quantity of a gain control circuit for the primary color due to variance among elements such as transistors at the time of image adjustments in a cathode-ray tube display. SOLUTION: This display is equipped with a gain control means 10 which inserts a white signal for detection into a video signal to be displayed in a vertical blanking period, detects the corresponding cathode current in the detection timing of the white signal, and performs negative feedback control over the amplification gain of the video signal so that the detected value reaches a target value 17 and a means which increases and decreases the level of the white signal for detection performs negative feedback control over the gain of the video signal applied to the cathode to increase or decrease the optical white level of the screen while holding the proportional relation among the primary colors. |
