| 摘要 |
PURPOSE:To generate a horizontal deflection beam with an excellent linearity by selecting a digital control data in response to the tube face of a cathode ray tube. CONSTITUTION:A supply voltage VL whose value is a minimum value at a phase corresponding to that at scanning of both ends of a cathode ray tube B and a maximum value at a phase corresponding to that at the scanning of the middle of the screen and whose value is varied continuously is supplied from a variable voltage source 2 to a horizontal deflection coil LH, and a correction horizontal deflection current ILH flows to the horizontal deflection coil LH. A waveform of the correction horizontal deflection current ILH is symmetrical in both the polarities around a point of time corresponding to the center of the tube screen and corrected in the S shape by the action with a transistor(TR) turned on/off by a damper diode D and a change in a base voltage VB. Thus, the deflection angle of the horizontal deflection beam BM in the unit time is theta1 at ends of the tube screen and theta2 in the center of the screen (theta1<theta2) and values of scanning distances l1, l2 per unit time corresponding to the deflection angles theta1, theta2 are made equal to each other and the horizontal linearity is improved. |
