摘要
目的建立一个可减小组织阻抗动态变化影响的多频电阻抗断层成像数据采集系统。方法采用数字合成技术产生含有4种频率分量的激励信号,将其注入成像目标,然后采用正交序列数字解调法提取各频率分量下的阻抗信息。结果所实现的成像系统可工作于1.6～380kHz。在100kHz时,该系统仍具有65dB的共模抑制比。工作频率范围内,100Ω电阻上的测量精度优于-80dB。基于物理模型的成像结果可清楚的反映出模型内阻抗实、虚部等参数的变化情况。结论所建立的多频成像系统具有较高的测量精度,能够满足多频成像研究需要。
Objective To establish a data acquisition system for multi-frequency electrical impedance tomography （EIT） that can diminish the effect of the dynamic change of tissue impedance. Method A driving signal with four frequency components was produced based on digital synthesis technique. The driving signals were injected into the imaging object, and impedance information at each frequency was extracted by orthogonal sequential digital demodulation method. Result The established system could work at a wide range of frequencies from 1.6 kHz to 380 kHz. Its common mode rejection ratio （CMRR） was 65 dB at 100 kHz. Measuring precision on a 100 D, resistor was better than -80 dB in full bandwidth. The images based on physical phantom could reflect the impedance parameter （such as real part and imaging part） changes inside the phantom clearly. Conclusion This multi-frequency EIT system has a high measuring precision, and meets the need of multi-frequency EIT research.
出处
《航天医学与医学工程》
CAS
CSCD
北大核心
2006年第1期47-50,共4页
Space Medicine & Medical Engineering
基金
国家自然科学基金(50337020)
关键词
多频电阻抗断层成像
组织阻抗频率特性
数字解调
数据采集系统
multi-frequency electrical impedance tomography
tissue＇s impedance frequency characteristics
digital demodulation
data acquisition system
