SHORT-TIME SIGNAL DETECTION CIRCUIT

PROBLEM TO BE SOLVED: To detect existence of such a noise as it is difficult to take a countermeasure by circuit technology by way of precaution against input of such a noise. SOLUTION: The circuit for detecting a short-time signal having a signal value not sustaining longer than a predetermined time with regard to a signal having a signal level varying between a first level and a second level comprises a timer 3, which is actuated upon input of a signal transiting in the direction from the second level to the first level and continues clocking, during the duration of a first level signal before the first level signal begins transition to the direction of second level; a means 13 for judging whether the duration of the first level signal is shorter than a predetermined time or not; and a first generation means 4 generating a signal for informing the fact that the duration of the first level signal is shorter than a predetermined time as a result of judgment. COPYRIGHT: (C)2008,JPO&INPIT