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探索一种简便的聚焦超声功率测量方法,利用压电陶瓷片直接接收超声信号,通过机电类比得到压电瞬态响应由压电片在声波作用力下引起受迫振动产生的电压响应与固有振动产生的高频衰减响应叠加而成,分析输出压电信号与换能器声功率之间的换算关系。对输出压电信号进行二次包络提取,获得表征声功率变化的电压幅度曲线,分别找出不同换能器驱动电压下包络曲线的最大峰值电压,将其平方值与声功率计所测声功率进行线性拟合,并对理论关系式中的比例系数进行标定。实验结果所得线性拟合度较高,且标定后所得声功率与声功率计所测值相对误差低于8.7%,证明了通过压电瞬态响应测量换能器声功率具有可行性。
A simple method to measure focused ultrasonic power is explored. The piezoelectric ceramic chip receives the ultrasonic signal directly, and the piezoelectric transient response is obtained by the electromechanical analogy. The voltage response caused by the forced vibration of the piezoelectric film caused by the sound wave and the natural vibration The resulting high-frequency attenuation response is superimposed, the analysis of the output piezoelectric signal and the conversion between transducer power relationship. The output voltage signal is extracted by the second envelope to obtain the voltage amplitude curve which characterizes the change of the sound power, and the maximum peak voltage of the envelope curve under different driving voltage of the transducer is respectively found. The square value thereof is compared with the measured value of the sound power meter The acoustic power is linearly fitted and the scale factor in the theoretical relationship is calibrated. The experimental results obtained a high linear fit, and the relative error between the measured sound power and the measured sound power meter was less than 8.7%. It is proved that it is feasible to measure the transducer acoustic power through the piezoelectric transient response.