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厚度方向极化的圆片状压电换能器已经广泛地被用到声波成象测井仪和 CET水泥胶结质量评价仪上。人们仅仅考虑了传播媒质对接收的声波信号的影响 ,而很少考虑声源对接收的声波信号的影响。文中分析了这种换能器的瞬态响应 ,建立了它的等效电路 ,推导出声波函数 ,并指出换能器在三种发射模式 :过阻尼、临界阻尼和振荡模式。只有振荡模式具有实际用途。换能器的发射模式由换能器的材料特性、周围耦合液体的机械负载和驱动电路的输出阻抗等因素决定。通过改变这些参数 ,可改变发射声波信号和声波成象的质量
Thickness-directionally polarized piezoelectric wafers have been widely used in acoustic imaging tools and CET cements. People only consider the influence of the propagation medium on the received acoustic signal, and seldom consider the influence of the sound source on the received acoustic signal. In this paper, the transient response of this transducer is analyzed, its equivalent circuit is established, the acoustic function is deduced, and the transducer is pointed out in three transmission modes: over damping, critical damping and oscillation mode. Only oscillation mode has practical use. The transmission mode of the transducer depends on the material characteristics of the transducer, the mechanical load of the surrounding coupled liquid, and the output impedance of the driver circuit. By changing these parameters, the quality of the transmitted acoustic signal and the acoustic image can be changed