[FieldTrip] 60 Hz notch using preprocessing
jan-mathijs schoffelen
jan.schoffelen at donders.ru.nl
Fri Oct 28 10:33:55 CEST 2011
Hi Francesco,
I suspect that the 60 Hz line noise is not of constant amplitude throughout the length of your trial (it seems you read in a whole session at once). Having, say, a 5-minute recording, notching out the 60 Hz with a dftfilter leads to a 1/300 Hz wide notch. This is probably too narrow given some slight 60 Hz amplitdue modulations. You could use a bandstop filter in this case.
Best,
Jan-Mathijs
On Oct 28, 2011, at 10:21 AM, Francesco Di Pompeo wrote:
> Dear all,
>
> I need a 60 Hz notch filter before the ICA of continuous 4D data.
> I did it using ft_preprocessing but the 60 Hz line is still there..
>
> Something wrong in my script?
>
>
> cfg = [];
> cfg.dataset = '0';
> cfg.channel = {'MEG', '-A246', '-A170', '-A110', '-A19'};
>
> cfg.bpfilter = 'yes';
> cfg.bpfreq = [1 150];
>
> cfg.dftfilter = 'yes';
> cfg.dftfreq = [60 120 180];
>
> data_meg = ft_preprocessing(cfg);
>
>
>
>
> -----------------------------------------------------------------
> Francesco Di Pompeo, PhD
> Institute of Advanced Biomedical Technologies and
> Department of Neuroscience and Imaging
> University of Chieti "G. d'Annunzio"
> Via dei Vestini - Campus Universitario
> 66013 Chieti - ITALY
> ph: +39-0871-3556907
> fax:+39-0871-3556930
>
>
>
> _______________________________________________
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> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
Jan-Mathijs Schoffelen, MD PhD
Donders Institute for Brain, Cognition and Behaviour,
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands
J.Schoffelen at donders.ru.nl
Telephone: +31-24-3614793
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