| 摘要 |
<P>PROBLEM TO BE SOLVED: To highly sensitively measure the intensity of material, the state of fatigue, and vibration phenomena. Ž<P>SOLUTION: Subharmonics, nonlinear waves, etc. arising from elastic vibration, are very faint vibration and necessitate measuring instruments of high sensitivity. This high performance material evaluator is obtained by forming an instrument for highly sensitively measuring a frequency-modulated ultrasonic nonlinear signal by using a correlator and a lock-in amplifier. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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