基于八电极的生物电阻抗分析检测系统设计

Design of Electrical Impedance Analysis System Based on Eight Electrodes

精确采集人体生物电阻抗信号,是人体成分分析的重要基础。设计一套测量生物电阻抗系统,利用MSP430主控芯片控制恒流源产生50-300KHz激励电流信号,并通过电极施加于被测人体不同部位,采用八电极多频率阻抗采集法,通过乘法解调对生物三元模型的阻容模型进行测量。实验结果表明,应用不同频率的激励电流信号对同一人体进行测量,不同部位的阻抗值幅值以及偏移相角不同,应选取合适的频率,使测量值与理论值误差达到极小、测量系统精度达到最优。

The basis of human component analysis is to accurately measure the biological electrical impedance value of human body.This article designed a set of bioelectrical impedance measurement system,using the MSP430 main control chipto control constant current source and produce 50-300 KHZ excitation current signal,and the electrode is applied on different parts of human body to be tested.Eight electrode impedance frequency acquisition method and the multiplication demodulation are employed to measure the resistance capacity model of the biological ternary model.The experimental results show that for the same measurement of bioelectrical impedance system,different exciting current frequency should be adopted to measure amplitude and phase angle,which comes closest to the measured value with the theoretical value and minimizes the error,therfore the precision of the measurement system can be achieved.