| 摘要 |
Improving reducing or eliminating the effects of variation in characteristics of the resonance circuit in a resonance type displacement detection apparatus, so as to improve displacement detection accuracy. In a displacement detection system 10 , the resonance frequency range assumable by the resonance circuit 21 is estimated in advance, there is determined a drive frequency variation range f 1 -f 2 such that the estimated resonance frequency range is included therein, and by means of a variable oscillator 30 , drive frequency is repeatedly varied between the first frequency f 1 and the second frequency f 2 . Accordingly, where the resonance frequency of the resonance circuit 21 is fr 1 , when the drive frequency has changed to fr 1 , resonance voltage Vgl 1 may be obtained in the case of large gap G. Where the resonance frequency of the resonance circuit 21 is fr 2 , when the drive frequency has changed to fr 2 , resonance voltage Vgl 2 may be obtained in the case of large gap G.
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