| 摘要 |
PURPOSE:To prevent a signal processing circuit from malfunctioning due to noise caused by in-tube discharge by detecting a picture tube in-tube discharge of a prescribed level or over and allowing the digital signal processing circuit to restore the initial data to the initial state again. CONSTITUTION:A malfunction preventing device 8 having a terminal 6 detecting generation of the in-tube discharge and an output terminal 7 applying the initial setting equal to power application again is added. Since an impedance 11 exists in the return to an external conductive film of the picture tube 5 of a spark gap 10, a potential of the earth terminal 6 of the gap 10 rises as a pulse the moment a spark is generated. After the pulse width is widened by a monostable multivibrator 13, an output 7 of an output buffer circuit 14 drives a power supply application detection circuit 1. Further, a voltage comparator 11 is set not to be activated with a light spark. |
