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Hi Francesco,<br>
<br>
Just as a small add to Eelke's reply, you can specify a bs-filter
for several ranges at once by doing it in a matrix, e.g.:<br>
cfg.bsfreq = [58 62; 118 122];<br>
Note though, these filters (at least the standard butterworth) get
increasingly inaccurate (less sharp filter-response, more
'filter-rolling'/edge-artifacts) when going to higher frequencies,
if you are using the same frequency-range-width. <br>
<br>
Best,<br>
Roemer<br>
<br>
<br>
On 28-10-11 10:36, Eelke Spaak wrote:
<blockquote
cite="mid:CABPNLUqcN-kCUuHzbYQ68foUyZzoFL-EnxkNTjHSH9O7fp9XKQ@mail.gmail.com"
type="cite">
<pre wrap="">Dear Francesco,
A notch filter is referred to as a band-stop filter in
ft_preprocessing's documentation, and is different from the
(regression-based) DFT filter. To use a notch filter, specify:
cfg.bsfilter = 'yes';
cfg.bsfreq = [58 62]; % or whatever you deem appropriate
Note that you will have to apply ft_preprocessing repeatedly if you
explicitly want to filter out the harmonics of the line noise as well.
Best,
Eelke
2011/10/28 Francesco Di Pompeo <a class="moz-txt-link-rfc2396E" href="mailto:f.dipompeo@unich.it"><f.dipompeo@unich.it></a>:
</pre>
<blockquote type="cite">
<pre wrap="">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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</pre>
</blockquote>
<pre wrap="">
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</pre>
</blockquote>
<br>
<div class="moz-signature">-- <br>
<font size="2"><font color="darkblue"><font face="calibri">Roemer
van der Meij M.Sc.<br>
PhD student<br>
Donders Institute for Brain, Cognition and Behaviour<br>
Centre for Cognition<br>
P.O. Box 9104<br>
6500 HE Nijmegen<br>
The Netherlands<br>
Tel: +31(0)24 3655932<br>
E-mail: <a class="moz-txt-link-abbreviated" href="mailto:r.vandermeij@donders.ru.nl">r.vandermeij@donders.ru.nl</a><br>
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