| 摘要 |
PURPOSE:To prevent the generation of lateral white noise on the screen of an image display while preventing interference other circuit blocks, by constituting a circuit in such a way that plural transistors (TR) are not turn on and off in a period other than a blanking period. CONSTITUTION:A signal VA from a vertical oscillating circuit 1 is applied to a flip-flop (F-F)19 through a switching TR16. When the VA is positive, the TR16 turns on, and a TR18, therefore, turns off. At this time, a TR20 turns off and the capacitor 6 of a charging and discharging circuit 7 is charged. When the capacitor 6 is charged up to the 1st reference voltage V2, a comparator 22 outputs a voltage VF and when up to the 2nd reference voltage V1, a comparator 21 operates turn on a resetting TR23 immediately and the FF19 is inverted to turn on the TR20, so that the capacitor 6 is discharged. Said operation is repeated to obtain a blanking signal at an output terminal 13 and a deflection driving pulse at an output terminal 27. |
