自易法测量矩形换能器超声功率研究

为能够精准且快捷地测量矩形换能器的声功率,探索一种基于自易校准技术测量矩形换能器超声功率的方法。首先利用自易校准方法中的电声互易原理,分析开路电压、第一回波电流与声功率之间的关系,推导出矩形换能器声功率自易测量计算的表达式,论述其中衍射系数的计算方法。然后使用自易法和辐射力天平法在不同激励电压下测量2个不同长宽比的矩形换能器,将2种方法所测超声功率分别与电功率、激励电压有效值的平方进行线性拟合,结果取得较好的一致性,并讨论该方法的适用范围。实验证明自易法用于矩形换能器超声功率测量具有可行性。

A method for measuring the ultrasonic power of a rectangular transducer accurately and quickly based on self-reciprocity technique was explored.Firstly,the electroacoustic reciprocity principle in the self-reciprocity calibration method was used to analyze the relationship between the open-circuit voltage,the first echo current and the ultrasonic power,the expression for the calculation of the rectangular transducer ultrasonic power was derived based on self-reciprocity measurement,and the calculation method of diffraction coefficient was discussed.Then,the ultrasonic power of two rectangular transducers with different aspect ratios were measured under different excitation voltages using self-reciprocity method and radiation force balance method.The results obtained by the two methods were linearly fitted with the electric power and the square of effective value of driving voltage,respectively.The results indicated that the measurement consistency of the two methods was good,which showed the effectiveness of self-reciprocity method for the measurement of rectangular transducer ultrasonic power.Finally,the applicable scope of the method was discussed.