| 摘要 |
PROBLEM TO BE SOLVED: To provide a CRT driving device capable of preventing mechanical abnormal vibration generated in an electron gun when a parabola wave form is applied to a CRT. SOLUTION: A dynamic focus horizontal parabola waveform shaping circuit 1 is composed of an IC having a multi-vibrator function. A resister R2, a resister R3 and a capacitor C4 constitute a time constant circuit and the time constant is set so that a frequency of a pulse waveform for a horizontal parabola waveform in the multi-vibrator IC may conform to a horizontal synchronization frequency. A frequency converting circuit 6 is connected to the time constant circuit. Only during a vertical blanking period, transistors Q1 and Q2 of the frequency converting circuit 6 are turned ON by a vertical synchronization signal and by changing the time constant of the time constant circuit, the frequency generated by the multi-vibrator is changed. COPYRIGHT: (C)2006,JPO&NCIPI
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