基于FFT和APFFT的同时多频阻抗信息提取方法研究

摘要

To measure the impedance information accurately of the Primary harmonic frequencies under Walsh excitation mode, this paper researches a extraction method of Multi-frequency-one-time complex impedance information .An algorithm using FFT combined with all phases FFT ( APFFT) was presented to extract the bio-impedance information ,thus overcoming the short-comings of large error of impedance measurement using traditional Fast Fourier Transform ( FFT) algorithm due to the data non-in-teger-period sampling.In order to verify the feasibility of the algorithm for bio-impedance measurement,the simulation experiment research for extracting complex impedance of 2R-1C Tissue model simplified was done .The simulation results show that the com-plex impedance measurement error is less than 0.5%by applying the algorithm both the data integer-period and non-integer-period sampling,meeting the requirements of the multi-frequency bio-impedance measuring system .%为实现Walsh激励模式下不同主谐波频点对应阻抗信息的准确测量，文中对同时多频阻抗信息提取方法进行了初步研究。提出了一种基于FFT和APFFT综合法提取生物电阻抗信息，克服FFT算法非周期采样时复阻抗提取误差大的缺陷。为验证FFT和APFFT综合法在生物电阻抗测量的可行性，对简化的2R－1C组织模型进行了复阻抗的测量实验，仿真结果表明，该方法无论在周期采样还是非周期采样条件下所测量的复阻抗误差均小于0．5％，满足多频系统中生物电阻抗测量要求。