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Hi Philip,
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<div>The error you run into seems a hard constraint for the ‘dftfilter', with the option ’neighbour’. This means that this type of filtering cannot be done if your trials are of different length.</div>
<div>In this case, I would recommend just using the default value for dftreplace.</div>
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<div>Best wishes and good luck,</div>
<div>Jan-Mathijs</div>
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<div class="">On 24 Aug 2022, at 16:57, philip Joadavi via fieldtrip <<a href="mailto:fieldtrip@science.ru.nl" class="">fieldtrip@science.ru.nl</a>> wrote:</div>
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<div dir="ltr" class="">Dear all,
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<div class="">I have a question (which might be very stupid) regarding the line noise removal using spectrum interpolation using DFT method.</div>
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<div class="">currently, I'm applying the notch filter on my data, but I noticed for some of my subjects the 50Hz is not entirely removed. </div>
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<div class="">I have 32-channel EEG data (with a sampling frequency of 2048) with many trials that have different lengths (from 15 seconds to 5 min). If I understood correctly the best method for removing the 50 Hz from this kind of data is spectrum interpolation.
Unfortunately, I'm having a hard time making it to work. </div>
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<div class="">here is what I have defined:</div>
<div class="">cfg.dftfilter = 'yes';<br class="">
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<div class="">cfg.dftreplace = 'neighbour';<br class="">
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<div class="">cfg.continuous = 'yes';<br class="">
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<div class="">cfg.padding = (2^nextpow2(size(Data{1}.trial,2)))/Data{1}.fsample</div>
<div class="">cfg.padtype = 'data'<br class="">
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<div class="">so, my first trial has a length of 368200, which for the cfg.padding I use 256. </div>
<div class="">here is where I'm stuck and apparently I'm doing something wrong, which gives me this error:<br class="">
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<div class="">=><b class=""> "Padding by data mirroring is not supported for spectrum interpolation"</b><br class="">
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<div class="">I also remove the option for continuous data, but it did not solve my problem.</div>
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<div class="">I would appreciate any help!</div>
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<div class="">Thanks a lot!</div>
<div class="">Philip</div>
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