低场核磁共振信号检测电路设计  

Design of low field NMR signal detection circuit

作　　者：邹庭浪 孙伟达 谢建军[1] 郭智勇[3] 邬杨波[1] ZOU Tinglang;SUN Weida;XIE Jianjun;GUO Zhiyong;WU Yangbo(Faculty of Electrical Engineering and Computer Science,Ningbo University,Ningbo 315211,China;Ningbo Mingrui ZTE Electronic Technology Co.,Ltd.,Ningbo 315105,China;School of Material Science and Chemical Engineering,Ningbo University,Ningbo 315211,China)

机构地区：[1]宁波大学信息科学与工程学院,浙江宁波315211 [2]宁波铭瑞中兴电子科技有限公司,浙江宁波315105 [3]宁波大学材料科学与化学工程学院,浙江宁波315211

出　　处：《宁波大学学报（理工版）》2022年第6期1-8,共8页Journal of Ningbo University：Natural Science and Engineering Edition

基　　金：国家自然科学基金(42076193);浙江省基础公益研究计划(LGF19B050003)。

摘　　要：核磁共振检测以其快速、不破坏样品、直观反映分子结构等优点在诸多领域有着非常广泛的应用.针对核磁共振检测仪器价格昂贵、体积庞大、操作复杂、不便于实现现场检测等问题,设计了一种面向小型化低成本低场核磁共振仪的核磁共振信号检测电路.所提出的电路使用低噪声前置放大器实现传感信号放大,基于锁定放大的微弱信号检测技术实现了对核磁共振回波信号的有效检测.实际测试结果表明,所设计的电路放大倍数高达20 000倍,在高倍噪声的干扰下能够准确检测出幅度在5μV及以上的有用信号.所提出的低场核磁共振信号检测电路对于发展低成本核磁共振仪器具有较好的应用价值.Nuclear magnetic resonance(NMR) detection has been widely used in many fields for its advantages of rapidity, non-destructive sample, and molecular structure visualization. To address the problems with NMR detection instruments, including high price, over-size, complicated operation, and poor operability of field detection, in this paper an NMR signal detection circuit is designed for miniaturized, low-cost low-field NMR instruments. The proposed circuit uses a low-noise preamplifier to amplify the sensing signal. The weak signal detection technique applied in locked amplification effectively detects the NMR echo signal. Test results show that the designed circuit magnifies up to 20 000 times. It can accurately detect useful signals at amplitudes of 5 μV and above under high noise interference. The proposed low-field NMR signal detection circuit has good application value for developing low-cost NMR instruments.

关 键 词：低场核磁共振信号检测 微弱信号检测 核磁共振 

分 类 号：TM937[电气工程—电力电子与电力传动]