TY  - JOUR
AU  - Huang, Xiaolei
AU  - Dong, Hui
AU  - Tao, Quan
AU  - Yu, Mengmeng
AU  - Li, Yongqiang
AU  - Rong, Liangliang
AU  - Krause, Hans-Joachim
AU  - Offenhäusser, Andreas
AU  - Xie, Xiaoming
TI  - Sensor Configuration and Algorithms for Power-Line Interference Suppression in Low Field Nuclear Magnetic Resonance
JO  - Sensors
VL  - 19
IS  - 16
SN  - 1424-8220
CY  - Basel
PB  - MDPI
M1  - FZJ-2019-04248
SP  - 3566 -
PY  - 2019
AB  - Low 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
LB  - PUB:(DE-HGF)16
C6  - pmid:31443310
UR  - <Go to ISI:>//WOS:000484407200123
DO  - DOI:10.3390/s19163566
UR  - https://juser.fz-juelich.de/record/864467
ER  -