电容式微机械超声换能器的信号调理电路设计

摘要

针对电容式微机械超声换能器(cMUT)的工作原理和检测要求,分析了换能器微弱回波信号的处理方法,设计了性能良好的信号调理电路,有效的解决了在实际应用中换能器模式转换和微弱信号调理的关键问题和首要难题.通过对电路系统的测试,实验结果表明该电路具有良好的线性和稳定性,且其带宽为1.53×108 Hz,灵敏度为0.161 mV/pF,分辨率为1 nA;其不仅实现了换能器收发一体及微弱信号调理的功能,而且还为换能器水下超声成像系统的建立奠定了基础.%Aimed at working principle and detecting demand of the capacitive micro-machined ultrasonic transducer (cMUT), a good performance signal processing circuit was designed through analyzing processing methods of weak echo signal of transducer, and effectively solved the key problem and primary difficulty which were transducer model transformation and weak signal conditioning in practical application.Through testing the circuit system, the experimental results showed that the circuit had great linearity and stability, and its bandwidth was 1.53×108 Hz, sensitivity was 0.161 mV/pF, and resolution was 1 nA.In this paper, the circuit not only implemented the function of transmission-receiving and weak signal processing of the cMUT, but also set base for building underwater ultrasonic imaging system of the cMUT.