基于DDS和DFT的水声换能器小信号阻抗测量

Research of Acoustic Transducer Small-Signal Impedance Measurement Base on the DDS and DFT

针对水声测量中换能器阻抗和功率放大器的匹配问题,以及换能器老化状况诊断的实际问题,利用DDS（直接数字合成）和DFT（离散傅里叶变换）技术,研究了使用小信号下换能器在不同频率点上的频率响应情况,通过执行多次测量,确定换能器的幅频响应特性曲线,以此分析换能器的老化情况,同时可以对功率放大器输出匹配电路设计提供参考。通过相关原理分析,设计了阻抗测试电路并编写了测试软件,经调试,该电路在系统中工作正常,成功完成换能器在小信号下的复阻抗测量,并对影响换能器阻抗的相关因素做出了分析。

Considering the practical problem of matching the acoustic transducer impedance to the power amplifiers and diagnosis of the aging status of the acoustic transducer,using DDS（Direct Digital Synthesizers） and DFT（Discrete Fourier Transform） technique,the frequency response of transducer under small-signal at different frequency point was studied.By performing multiple measurements to determine the transducer frequency response curves,the aging status of the transducer was analyzed and the information for the power amplifier circuit design was provided.Through the relevant principles of analysis,the impedance measurements circuit was designed,the software for test was written.After being debugged,the circuit in the system worked correctly and successful in the small-signal impedance measurement.At last,the related factors impact of the transducer impedance measurements were analyzed.