| 摘要 |
PURPOSE:To speedily attain the response of a circuit at the time of switching a vertical deflecting cycle, in a side pin cushion distortion correcting circuit used for a vertical deflecting frequency variable type display device. CONSTITUTION:Sawtooth currents Iy are running from a horizontal output circuit 2 to a horizontal deflecting coil 3. A sawtooth voltage Vst outputted from a waveform generating circuit 5 is shaped by a waveform shaping circuit 6, and a parabola-shaped waveform Vpb is outputted. A modulating circuit 7 modulates the amplitude of the sawtooth currents Iy by the waveform Vpb. Moreover, the waveform Vpb is rectified by a rectifying circuit 8, and turned to a direct current voltage Edi in proportion to the pp(peak-peak) value. A comparator 9 compares this voltage Edi with a reference direct current voltage Es, and controls the waveform generating circuit 5. And also, the phase of the waveform Vpb is a little shifted by a phase shifting circuit 25, and turned to a waveform Vps. An electronic switch 24 is conducted by the peak part of the waveform Vps, and the charge of the rectifying circuit 8 is discharged through an auxiliary load 23, so that the response at the time of switching the vertical deflecting cycle can be speedily attained. |
