[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
> 
> 
> 
> _______________________________________________
> fieldtrip mailing list
> 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

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20111028/99559699/attachment.html>


More information about the fieldtrip mailing list