[Eeglablist] question about filtering

[Karolina Broś]

Dear all,

I am preprocessing my data and I want to run ICA for artifact rejection on
1Hz-filtered data and then apply weights to 0.1Hz-filtered data...

>From what I understand, the EEGLAB *eegfiltnew *function uses passband
edges which do not exactly correspond to cutoff frequencies.

Am I right to assume that to get a 1Hz high-pass filter I should enter a
2Hz edge?

EEG = pop_eegfiltnew(EEG, [],2,[],true,[],1);

and to get 0.1 I should enter 0.2Hz?

EEG = pop_eegfiltnew(EEG, [],0.2,[],true,[],1);


Also, only theoretically, is it possible to high-pass filter data twice?
Would that distort the data and disable ICA?

Let's say we have a dataset filtered with a cutoff frequency of 0.1Hz but
then we want to run ICA at 1Hz because it's the recommended threshold... Is
it possible to take the 0.1 dataset and apply a more robust filter to it?

I would really appreciate your feedback!

Karolina



Institute of Applied Linguistics
University of Warsaw
ul. Dobra 55
00-312 Warszawa
*www.ils.uw.edu.pl <http://www.ils.uw.edu.pl>*

*www.karolinabros.eu <http://www.karolinabros.eu>*
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