标准超声换能器辐射电导的电学法测量

Measurement of Radiation Conductance Based on Electrical Method for Standard Ultrasonic Transducers

基于串联共振等效电路得到的超声功率表达式,阐述了用4192A型阻抗分析仪测量标准超声换能器辐射电导的方法.将电学法测量的辐射电导与基于辐射压力法的毫瓦级超声功率国家基准装置的测量结果进行了比较,结果表明:标称频率为2.5、5.0MHz的石英晶体标准换能器的辐射电导的测量误差分别为0.35%和2.11%,在电压表误差≤1%的情况下,可以保证换能器辐射的超声声功率误差≤3%.实验研究证实该方法是一种简便、准确可靠的方法,不但可以对使用辐射压力法所得到的结果进行比对,也可以作为新的计量基准或标准使用.

According to the expression of ultrasonic power based on the series resonant equivalent circuits, a method to measure the radiation conductance of standard ultrasonic transducer with a 4192A impedance analyzer is presented. The radiation conductance measured by the electrical method is then compared with that obtained by the national primary standard equipment for milliwatt ultrasonic power based on the radiation pressure method. The results indicate that the errors of radiation conductance of quartz-crystal, standard transducers with the nominal frequencies of 2. 5 and 5.0 MHz are respectively kept at 0. 35% and 2. 11% , that the en＇or of uhrasonie power of transducers is not greater than 3% when the error of voltmeter is not greater than 1%. Moreover, it is found from experimental results that the proposed method with simplicity and reliability can not only test the standard transducers whose ultrasonic powers are measured by means of the radiation pressure method but also act as a new measurement standard.