VIBRATION STATE DETECTING DEVICE

摘要

PROBLEM TO BE SOLVED: To always detect correct positions regardless of the change of outside environ ment in a vibration state detecting device for detecting the position and the amplitude of an object of detection which moves to and fro. SOLUTION: In this vibration state detecting device, the potential of a detection end Td with respect to the reference end Tf of a sensor coil 12 at the time a movable part 4 approaches a reference position (θ=0 deg.) becomes a polarity reverse to that at the time the movable part 4 separates from the reference position and an amplifier 18 amplifies this potential difference to generate a detection signal A whose signal level changes around a reference voltage Vc as a center by an amount equivalent to the amplification. A positional signal P is generated at timing when the magnitude relation between detection data D which are obtained by converting the signal level of the detection signal A in an A/D converter 20 and a comparison level Ref set in a comparison level holding part 28 is reversed. Moreover, the comparison level Ref which is set based on the detection data D which can be obtained when the input of the amplifier 18 is short-circuited becomes a level which coincides correctively with the signal level of the detection signal A which is to be detected when the movable part 4 is confronted with the reference position by including an offset to be given to the amplifier 18.