用于生物阻抗测量的双反馈电流源研究  

Study on Double Feedback Current Source for Biologic Impedance Measurement

作　　者：王超[1] 王湘嵛[1] 孙宏军[1] 王化祥[1] 

机构地区：[1]天津大学电气与自动化工程学院,天津300072

出　　处：《生物医学工程学杂志》2006年第4期704-707,共4页Journal of Biomedical Engineering

基　　金：国家自然科学基金资助项目(60301008;50337020);天津市自然科学基金资助项目(013614411);天津大学青年教师基金资助项目

摘　　要：针对生物阻抗测量中电流源在较高频率时,恒流特性较差的问题,以及对其消除直流信号能力的要求,设计了双反馈电流源方案,基于第二代电流传输器(CC II)原理设计的电压控制电流源,通过增加直流反馈单元和输入缓冲,获得了良好的输出阻抗和抗直流特性,并通过使用直接数字合成(DDS)和乘法解调技术,实现了电流幅值的闭环控制,进一步提高了电流源的恒流特性。A double feedback current source for biologic impedance measurement is designed in order to solve the problem on the poor constant-current characteristic under higher frequency and meet the request for the ability to eliminate the direct current signal. The voltage controlled current source based on the second generation current conveyor theory is presented, which has good output impedance and antl-dlrect current characteristics by using the direct current feedback unit and input buffer. The closed loop control of current amplitude is implemented by means of the direct digital synthesizer and multiplication demodulation technlque, which improves the constantcurrent characteristic of the current source.

关 键 词：生物阻抗测量 第二代电流传输器 电压控制电流源 直接数字合成 双反馈 

分 类 号：TH772[机械工程—仪器科学与技术]