| 摘要 |
The invention relates to a method and apparatus for testing the motor and generator properties of a piezoelectric transducer; for evaluating the effects of an interface between an object of study and the piezoelectric element; and for analyzing the resonance frequencies of the object of study. The method consists of isolating and analyzing the freely oscillating decay signal of a piezoelectric transducer. This signal provides the standard for evaluating the piezoelectric transducer. This signal can also be compared with the freely oscillating decay signal of the transducer connected to an object for the purpose of analyzing the interface between the transducer and the object and the resonance frequencies of the object. To isolate the freely oscillating decay signal of the transducer, an apparatus may be used employing a square wave generator suppling an electric pulse through an electronic switch to a piezoelectric transducer. This causes the transducer to oscillate periodically and emit a signal when the pulse is applied and when it is released. The electronic switch cuts off the stress impulse, allowing the transducer to oscillate freely. The combined signal from the square wave generator and the transducer is then amplified and limited by a limit comparator and amplifier. This reduces the size of the square wave impulse and amplifies the transducer signal. The remainder of the square wave impulse is eliminated from the output signal permitting discrete analysis of the transducer signal.
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