数字式平均法提高MRS探测信噪比应用研究 .pdfVIP

学兔兔 第33卷 第3期 仪 器 仪 表 学 报 V01．33 No．3 2012年3月 Chinese Journal of Scientific Instrument Mar．2012 数字式平均法提高MRS探测信噪比应用研究术 林 君，张 哲，王应吉，孙淑琴，尚新磊 (地球信息探测仪器教育部重点实验室吉林大学仪器科学与电气工程学院 长春 130061) 摘 要：针对核磁共振地下水探测仪信号甚微弱导致信噪比太低的问题，分析了野外施工环境电磁干扰的特点，设计了数字式 平均型数据采集与数据预处理系统。把一次测量时间内的信号分成若干个时间间隔小段的信号，然后对这些信号进行取样，将 各次测量中处于相同位置的取样进行积分平均。研究结果应用于JLMRS(Jilin magnetic resonance souding)型核磁共振地下水探 测仪中，实验室与野外探测结果表明，数字式平均方法改善核磁共振地下水探测仪信号的信噪比是有效的、可行的。 关键词：数字式平均；核磁共振法；信噪比；信噪改善比 中图分类号：TH763．1 文献标识码：A 国家标准学科分类代码：460．40 Research on improving SNR of MRS detection with digital average method Lin Jun，Zhang Zhe，Wang Yingji，Sun Shuqin，Shang Xinlei (Lab．of Geo—Exploration and Instrumentation，Ministry of Education of China， College of Instrumentation and Electrical Engineering，Jilin University，Changchun 130061，China) Abstract：Magnetic resonance sounding(MRS)signal is very weak and also sensitive to electromagnetic interference (noise)，the signal to noise ratio(SNR)is low．According to the characteristic of electromagnetic noise in field en— vironment，a digital average sampling and pre-processing system was designed．The periodic MRS signal is divided into several little interval segments and sampled，and integral average is performed on the samples at the same place of the little segments．The system was applied in the Jilin magnetic resonance souding(JLMRS)instrument f0r groundwater exploration．The results of laboratory test and field detection show that the digital average method is ef- fective and feasible to improve the signal to noise ratio of MRS signa1． Key words：digital average；magnetic reson