| 摘要 |
PROBLEM TO BE SOLVED: To reduce the sensitivity irregularity of a contactless type AE sensor having no active element in its rotary part and to easily detect whether the contactless type AE sensor gets out of order. SOLUTION: The contactless type AE sensor is equipped with the rotary part 40 provided to the end part of the rotary shaft of a rotor and constituted of an AE converter 31 and a first inductance element 41 and the fixing part 50 provided in opposed relation to the rotary part and having the second inductance element 51 electromagnetically coupled with the first inductance element 41, a transmission circuit 61 for applying a pulse signal to the second inductance element and a receiving circuit 62 for detecting the electric signal of the second inductance element. The fixing part 50 is equipped with a variable gain amplifier 64, an AD converter 65, a spectrum analyzing part 66 for performing the spectral analysis of a digital signal to calculate the spectral intensity of the frequency component of a detection target and a gain control part 66 for controlling the gain of the variable gain amplifier so as to make the spectral intensity constant. COPYRIGHT: (C)2009,JPO&INPIT
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