| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately detect a signal period. <P>SOLUTION: By selectively making to pass low frequency components of the concerned signal PS by an LPF section 120 which received the rectangular pulse signal PS sent from a signal generation source 210, such a signal LS is created that a fall change via a prescribed value is a change of a monotonous decrease in a period of a time width of a sampling period including a time point becoming the prescribed value. A signal value of such signal LS is detected with the sampling period by an A-D conversion section 130, and when the change of continuously detected two signal values forms a decrease change and also the signal value is determined as to be made via the prescribed value in the sampling time periods of the two signal values, information of the via-time when the signal value of the signal LS becomes the prescribed value is calculated based on the two signal values by a via-time calculation section 140. A period calculation section 160 calculates a generation period of the fall change by using the information of continuously calculated two via-time. <P>COPYRIGHT: (C)2013,JPO&INPIT |
