{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,25]],"date-time":"2026-02-25T16:23:38Z","timestamp":1772036618020,"version":"3.50.1"},"reference-count":39,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2019,8,15]],"date-time":"2019-08-15T00:00:00Z","timestamp":1565827200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["11874378"],"award-info":[{"award-number":["11874378"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>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) &lt; 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 &gt; 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.<\/jats:p>","DOI":"10.3390\/s19163566","type":"journal-article","created":{"date-parts":[[2019,8,15]],"date-time":"2019-08-15T11:11:00Z","timestamp":1565867460000},"page":"3566","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Sensor Configuration and Algorithms for Power-Line Interference Suppression in Low Field Nuclear Magnetic Resonance"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7526-9894","authenticated-orcid":false,"given":"Xiaolei","family":"Huang","sequence":"first","affiliation":[{"name":"State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050, China"},{"name":"CAS Center for ExcelleNce in Superconducting Electronics (CENSE), Shanghai 200050, China"},{"name":"Institute of Complex System (ICS-8), Forschungszentrum J\u00fclich (FZJ), D-52425 J\u00fclich, Germany"},{"name":"Joint Research Institute on Functional Materials and Electronics, Collaboration between SIMIT and FZJ, D-52425 J\u00fclich, Germany"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6444-1134","authenticated-orcid":false,"given":"Hui","family":"Dong","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050, China"},{"name":"CAS Center for ExcelleNce in Superconducting Electronics (CENSE), Shanghai 200050, China"},{"name":"Joint Research Institute on Functional Materials and Electronics, Collaboration between SIMIT and FZJ, D-52425 J\u00fclich, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Quan","family":"Tao","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050, China"},{"name":"CAS Center for ExcelleNce in Superconducting Electronics (CENSE), Shanghai 200050, China"},{"name":"Joint Research Institute on Functional Materials and Electronics, Collaboration between SIMIT and FZJ, D-52425 J\u00fclich, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mengmeng","family":"Yu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050, China"},{"name":"CAS Center for ExcelleNce in Superconducting Electronics (CENSE), Shanghai 200050, China"},{"name":"Joint Research Institute on Functional Materials and Electronics, Collaboration between SIMIT and FZJ, D-52425 J\u00fclich, Germany"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yongqiang","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050, China"},{"name":"CAS Center for ExcelleNce in Superconducting Electronics (CENSE), Shanghai 200050, China"},{"name":"Joint Research Institute on Functional Materials and Electronics, Collaboration between SIMIT and FZJ, D-52425 J\u00fclich, Germany"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, 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