[FieldTrip] power line filter
jan-mathijs schoffelen
jan.schoffelen at donders.ru.nl
Tue Oct 4 15:18:53 CEST 2011
Hi Davide,
If you pad up to 10 seconds, you may change the filterfreqs into:
filterfreqs = [49:0.1:51 99:0.1:101 149:0.1:151].
Notice the 0.1, rather than the 1. This is because a 10-second segment of data has an intrinsic frequency resolution of 0.1 Hz.
Note that this may make the code rather slow to run. Wouldn't it more sensible then to use a bsfilter?
Best,
JM
On Oct 4, 2011, at 3:05 PM, Davide Rivolta wrote:
>
> Dear all,
>
> I am trying to get rid of the power line noise. I use the dftfilter as indicated on the website.
>
> This works very well for most of the subjects. However, for some of them, I still get the noise.
>
> My trials have a different lenght: between 500 ms until 3 seconds.
>
> This is the script I used.
>
>
> filterfreqs = [49:1:51 99:1:101 149:1:151];
>
> cfg.dftfilter = 'yes';
> cfg.dftfreq = filterfreqs;
> cfg.padding = 10;
>
> dataprepro_syn = ft_preprocessing(cfg);
>
>
> The pad of 10 is the same as another already published study that used the same task.
>
>
> Attached is a picture of the problem (blu is baseline, red is stimulus). This is the result of multitepering (dpss).
>
>
> Thanks for your help,
>
> Davide
>
>
>
>
> <FMA14_power_spectra1.png>_______________________________________________
> 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/20111004/085fbdb0/attachment-0001.html>
More information about the fieldtrip
mailing list