Sensor Configuration and Algorithms for Power-Line Interference Suppression in Low Field Nuclear Magnetic Resonance
AbstractLow field (LF) nuclear magnetic resonance (NMR) shows potential advantages to study pure heteronuclear J-coupling and observe the fine structure of matter. Power-line harmonics interferences and fixed-frequency noise peaks might introduce discrete noise peaks into the LF-NMR spectrum in an open environment or in a conductively shielded room, which might disturb J-coupling spectra of matter recorded at LF. In this paper, we describe a multi-channel sensor configuration of superconducting quantum interference devices, and measure the multiple peaks of the 2,2,2-trifluoroethanol J-coupling spectrum. For the case of low signal to noise ratio (SNR) < 1, we suggest two noise suppression algorithms using discrete wavelet analysis (DWA), combined with either least squares method (LSM) or gradient descent (GD). The de-noising methods are based on spatial correlation of the interferences among the superconducting sensors, and are experimentally demonstrated. The DWA-LSM algorithm shows a significant effect in the noise reduction and recovers SNR > 1 for most of the signal peaks. The DWA-GD algorithm improves the SNR further, but takes more computational time. Depending on whether the accuracy or the speed of the de-noising process is more important in LF-NMR applications, the choice of algorithm should be made. View Full-Text
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Huang, X.; Dong, H.; Tao, Q.; Yu, M.; Li, Y.; Rong, L.; Krause, H.-J.; Offenhäusser, A.; Xie, X. Sensor Configuration and Algorithms for Power-Line Interference Suppression in Low Field Nuclear Magnetic Resonance. Sensors 2019, 19, 3566.
Huang X, Dong H, Tao Q, Yu M, Li Y, Rong L, Krause H-J, Offenhäusser A, Xie X. Sensor Configuration and Algorithms for Power-Line Interference Suppression in Low Field Nuclear Magnetic Resonance. Sensors. 2019; 19(16):3566.Chicago/Turabian Style
Huang, Xiaolei; Dong, Hui; Tao, Quan; Yu, Mengmeng; Li, Yongqiang; Rong, Liangliang; Krause, Hans-Joachim; Offenhäusser, Andreas; Xie, Xiaoming. 2019. "Sensor Configuration and Algorithms for Power-Line Interference Suppression in Low Field Nuclear Magnetic Resonance." Sensors 19, no. 16: 3566.
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