Comparison and optimal parameter settings of referencebased harmonic noise cancellation in time and frequency domains for surface-NMR
Comparison and optimal parameter settings of referencebased harmonic noise cancellation in time and frequency domains for surface-NMR
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DOI：
10.3997/1873-0604.2013033
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发表时间：
2014-04
影响因子：
1.6
通讯作者：
M. Müller‐Petke;S. Costabel
中科院分区：
文献类型：
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作者：
M. Müller‐Petke;S. Costabel
表面核磁共振（surface- nmr）技术提供了孔隙度和水力导电性的信息，在水文地质背景下具有很高的价值。然而，表面核磁共振的适用性往往受到较差的信噪比的限制。本文详细介绍了基于远程参考的谐波噪声消除技术，以提高信号的信噪比。我们给出了许多综合实例来研究各种参数的影响，如时域方法的最佳滤波器长度或频域方法的必要记录长度，所有这些参数都针对不同类型的噪声条件进行了评估。结果表明，频域方法优于时域方法。我们证明了频域中的参数设置和是否使用分离噪声测量的决定取决于实际噪声特性，即频率含量或随时间的稳定性。我们使用两个字段示例来强调我们的结果。
The technique of surface nuclear magnetic resonance (surface-NMR) provides information on porosity and hydraulic conductivity that is highly valuable in a hydrogeological context. However, the applicability of surface-NMR is often limited due to a bad signal-to-noise ratio. In this paper we provide a detailed insight into the technique of harmonic noise cancellation based on remote references to improve the signal-to-noise ratio. We give numerous synthetic examples to study the influence of various parameters such as optimal filter length for time- domain approaches or the necessary record length for frequency-domain approaches, all of which evaluated for different types of noise conditions. We show that the frequency-domain approach is superior to time-domain approaches. We demonstrate that the parameter settings in the frequency domain and the decision whether or not to use separated noise measurement depend on the actual noise properties, i.e., frequency content or stability with time. We underline our results using two field examples.