Overhauser磁力仪低噪声信号处理技术  

Low noise signal processing technology of Overhauser magnetometer

作　　者：郭培培[1,2] 董浩斌[1,2] 葛健[1,2] 罗望[1,2] 

机构地区：[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

出　　处：《中国测试》2017年第6期123-128,共6页China Measurement & Test

基　　金：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)

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 d B,研制的Overhauser磁力仪磁场测量精度0.2 n T,性能接近商用仪器水平,证明其在磁场测量中的有效性。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.

关 键 词：Overhauser效应 噪声模型 LC谐振 FID信号 

分 类 号：TN722.71[电子电信—电路与系统]