| 摘要 |
PURPOSE:To shorten an adjustment time and to make adjustment uniform, by providing a high-voltage generating circuit for generating a focusing voltage to the 3rd grid of each image pickup tube in a multitude color camera, and obtaining the extent of correction from a phase difference from a reference video signal. CONSTITUTION:The vertical and horizontal alignment coils 2 and 3 of image pickup tubes 1 are controlled by current control circuits 7 and 8, and constant current sources 4 and 5. The 3rd grid of each image pickup tube 1 is controlled by a high voltage generating circuit 6 and a focus voltage control circuit 9. A target test pattern is shot matching with the area of deflection and under the command of a microprocessor 13, a red focusing voltage is varied positively and negatively by a certain amount through the circuit 9. At this time, a green or blue video (reference) signal is selected by a multiplexer 10, and a phase difference detector 11 detects the phase difference between a horizontal and a vertical signal. A processor 13 calculates the extent of correction and the focusing voltage of the circuit is controlled to obtain a permissible error, thus automatically adjusting aligment correction. |
