| 摘要 |
PURPOSE:To obtain accurate side pin cushion distortion correcting effect by forming a distortion correction waveform while a sliced waveform passes through an integration circuit. CONSTITUTION:Upper/lower edge of vertical sawtooth wave voltage Vst is sliced by a waveform slicing circuit 7 to be a sawtooth waveform voltage Vst' and when it is given to an integration circuit 5, it is converted into a pseudo hiperbolic waveform Vhp of vertical period and the result is fed to a horizontal amplitude modulation circuit 6. Thus, a 1st slice diode 11 is conductive during a time T1 near the start point of vertical scanning period Tv and a 2nd slice diode 14 is conductive during a time T2 near the end point of the vertical scanning period Tv. The ratio of the conduction time of the diodes 11, 14 is set freely depending on the value of resistors 9, 10, 13. As a result, nearly linear change is attained near the start and end point of the vertical scanning period and the curve is close to a hiperbolic curve and accurate SPC distortion correction is applied. |
