1. Figure 5. Time-series and spectra of a noise-only record before (a and c) and after (b and d) model-based subtraction of powerline harmonics. The model is determined from the entire time-series and include all harmonics from 1 to 100. After subtraction of powerline harmonics, the presence of a number of small spikes is evident in b). These spikes are also present in the time-series in (a), but masked by powerline harmonic noise.
From: Noise cancelling of MRS signals combining model-based removal of powerline harmonics and multichannel Wiener filtering
Geophys J Int. 2013;196(2): doi: /gji/ggt422
Geophys J Int | © The Authors Published by Oxford University Press on behalf of The Royal Astronomical Society. 1