作者：郭培培1,2, 董浩斌1,2, 葛健1,2, 罗望1,2
作者单位：1. 中国地质大学（武汉）自动化学院, 湖北 武汉 430074;
2. 武汉中地资环工研院管理有限公司, 湖北 武汉 430074
关键词：Overhauser效应;噪声模型;LC谐振;FID信号
摘要：
针对磁力仪输出信号信噪比低的问题，同时为给Overhauser磁力仪的研制提供参考依据，提出一种低噪声信号处理技术。首先根据质子旋进信号(FID)特点，建立系统噪声模型，分析探头电阻热噪声和放大器等效输入噪声对测量造成的影响，提出LC谐振方案和低噪声放大电路以提高系统信噪比并通过实验测试仪器噪声水平。最后，将所研制的磁力仪与商用磁力仪进行对比测试，实验表明：提出的信号处理技术能有效降低系统噪声，FID信号信噪比＞36 dB，研制的Overhauser磁力仪磁场测量精度0.2 nT，性能接近商用仪器水平，证明其在磁场测量中的有效性。
Low noise signal processing technology of Overhauser magnetometer
GUO Peipei1,2, DONG Haobin1,2, GE Jian1,2, LUO Wang1,2
1. School of Automation, China University of Geoscience, Wuhan 430074, China;
2. Wuhan Industrial Technology Research Institute of Geo-resources and Environment Co., Ltd., Wuhan 430074, China
Abstract: In order to improve the low signal-to-noise radio of magnetometer and provide a basic reference for Overhauser magnetometer development, a low noise signal processing technology was proposed in this paper. Firstly, according to the characteristics of the free induction decay (FID) signal, this paper focused on analyzing the system noise model and discussing the influence of the sensor resistance thermal noise and the equivalent input noise of the amplifier on the measurement. Secondly, the LC resonance scheme and the low noise amplifier circuit were designed to reduce the noise, and the noise level of the instrument was tested. Finally, the experimental data in case of using the proposed device were compared with the commercial instrument. The comparisons indicate that the proposed method of signal processing can effectively reduce the system noise, the signal-to-noise radio is more than 36 dB and the measurement precession of magnetic field of developed Overhauser magnetometer is 0.2 nT and its performance is close to the commercial instrument, which proves its validity of the magnetic field measurement.
Keywords: Overhauser effect;noise model;LC resonance;FID signal
2017, 43(6): 123-128 收稿日期: 2016-10-15;收到修改稿日期: 2016-12-03
基金项目: 国家自然科学基金（41474158，41504137）国家重大科学仪器设备开发专项（2014YQ100817）
作者简介: 郭培培(1991-),女,河南濮阳市人,硕士研究生,专业方向为地球物理仪器及微弱信号检测。
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