| 摘要 |
PURPOSE:To correct a distortion and to eliminate an adverse influence to a horizontal deflecting circuit according to the fluctuation of the frequency of a vertical synchronizing signal and the fluctuation of the picture display width in a vertical direction by applying a different processing to the detected voltages during a vertical scanning period and a vertical retrace line period in a sample hold circuit to output and forming a correcting signal for a right and left pin cushion distortion by the output. CONSTITUTION:The sample hold circuit 18 holds the detected voltage inputted during the vertical retrace line period to a constant voltage so as to remove a spike form voltage generated during the vertical retrace line period of the cause of the malfunction of the horizontal deflecting circuit. Namely, in the sampling hold circuit 18, a path for passing an input voltage through a diode 6 and a path for holding a peak by a diode 7 and a capacitor 8 are disposed to output the signal of either one path by switching an analog switch 9. Thereby, in order to correct the right and left pin cushion distortion, a required and ideal parabola waveform is obtained and a distortion correcting circuit having no malfunction of other circuits is obtained. |
