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高强度聚焦超声(HIFU)换能器是HIFU治疗系统的关键部件,其电阻抗特性是决定各系统参数和换能器工作特性的重要参数。目前采用的阻抗分析仪和频域测量方法成本较高,且难以实现在线测量。为此,对基于脉冲响应的超声换能器电阻抗时域测量方法进行了研究,对测量原理进行了理论分析和仿真验证,并组建了脉冲响应测量实验平台,通过实际测量,比较了脉冲响应法和阻抗分析仪的测量结果,分析了影响测量结果的因素。研究结果表明:在通过电流取样电阻校正和小波去噪后,基于脉冲响应的电阻抗测量方法能取得较高的测量准确度,且测量成本低,可集成于设备实现超声换能器电阻抗的在线测量,为进一步研究高强度聚焦超声换能器的电阻抗特性提供了有力的手段。
High-intensity focused ultrasound (HIFU) transducers are key components of HIFU therapy systems and their electrical impedance properties are important parameters that determine the system parameters and transducer operating characteristics. Impedance analyzers and frequency domain measurement methods currently used are costly and difficult to implement on-line measurements. Therefore, the time-domain measurement method of the electrical impedance of the ultrasonic transducer based on impulse response is studied. The principle of the measurement is theoretically analyzed and verified by simulation. The impulse response measurement experiment platform is set up. By comparing the impulse response Method and impedance analyzer measurements, analyzed the factors that affect the measurement results. The results show that the electrical impedance measurement method based on impulse response can achieve higher measurement accuracy and lower measurement cost through current sampling resistance correction and wavelet denoising, which can be integrated in the device to achieve the electrical impedance of ultrasonic transducer On-line measurement provides a powerful tool for further study on the electrical impedance characteristics of high-intensity focused ultrasound transducers.