| 摘要 |
PURPOSE:To exactly correct the vertical pincushion distortion regardless of voltage fluctuation in a high voltage power source by providing a voltage detection circuit to detect the voltage of the high voltage power source and a voltage amplitude control circuit to control the voltage amplitude of a waveform for correcting the vertical pincushion distortion according to the voltage detected by this detection circuit. CONSTITUTION:A distortion correcting waveform amplitude control circuit 10 is provided to control the output waveform of a balanced modulation circuit 11 according to the voltage detected by a voltage detection circuit 9. When the voltage of the high voltage power source is lowered, the output waveform amplitude of the distortion correcting waveform amplitude control circuit 10 is decreased and when the voltage of the high voltage power source is boosted, the output waveform amplitude of the above mentioned control circuit 10 is increased. Thus, regardless of the fluctuation in the high voltage power source, optimum correction can be always executed. For example, when the high voltage power source is fluctuated and raster distortion is generated on a screen, the output of the balanced modulation circuit 11 is impressed to a vertical pincushion distortion correcting waveform output circuit 8 by the control circuit 10. By making a current flow to a vertical deflecting coil, the optimum correction can be executed to the vertical pincushion distortion. |
