同时多频生物电阻抗测量系统解调电路的设计

Design of Demodulation Circuit for Multi-Frequency-One-Time Bioelectrical Impedance Measurement System

为获得生物体内不同组织、器官同一时间的阻抗值,设计了一套用于同时多频生物电阻抗测量的解调电路系统,系统包括选频模块、模拟乘法器模块等主要硬件电路。将各模块集成,经测试:解调系统工作频率10Hz～1MHz,在500kHz时,系统仍具有80dB的共模抑制比,系统对阻抗模型的测量结果能以不超过1.92%的误差准确反映模型内阻抗实部、虚部的参数信息;实验结果表明:该解调系统共模抑制比高、测量准确度好,满足同时多频生物电阻抗测量系统的要求。

To acquire the impedance of different tissues and organs at the same time, this paper designs a demodulation circuit for the Multi-Frequency One-Time （MFOT） bioelectrical impedance measurement system based on frequency selection and analog multiplier module. The demodulation system works at 10Hz-IMHz. Its common mode rejection ratio （CMRR） is 80dB at 500NHz. The demodula tion results with the error less than 1. 92%reflect the real part and imaging part parameters of impedance models clearly. This design saris ties the requirement of bioelectrical impedance measurement system with high CMRR and excellent measurement accuracy.