| 摘要 |
PURPOSE:To increase the phase margin by selecting the polarity of division output in accordance with the result of phase comparison between a synchronizing signal and the division output of the output of an oscillator, and obtaining various types of driving pulses from a shift register which is driven by the division signal. CONSTITUTION:The output of a crystal oscillator 16 is sent to a frequency divider 18 and to a synchronizing signal generator 17. A phase detecting circuit 19 performs the phase comparison between the output of the divider 18 and the pulse signal of horizontal scanning period of the generator 17. The polarity of the divider 18 is selected in accordance with the result of said phase comparison. The selected signal is sent to a shift register 21 via a dividing circuit 27, and the output of the register 21 is converted into various types of driving pulses by decoders 23 and 24. Thus the phase margin is increased even though a phase difference produced between a pulse of horizontal scan period and an oscillation output signal. In such a way, the generation of the horizontal reading jitter is prevented. |
