[Eeglablist] causal filtering pop_eegfiltnew

[Daniele Marinazzo]

actually from what I see in eegfilt.m, if causal option is *on*, it uses
filter.m (phase shift introduced), otherwise is causal option is *off* it
uses filtfilt.m (no phase shift).

so, if you don't want the phase shift, you should *NOT* check the "use
causal filter" box.

do you confirm this, or is there a confusion with the nomenclature?

d.


On Wed, Apr 24, 2013 at 10:10 PM, Makoto Miyakoshi <mmiyakoshi at ucsd.edu>wrote:

> Dear Marta,
>
> > if i want to get a causal filter i should be using the 'legacy' version
> of the pop_eegfilt that uses fir1 and firfirl to filter the data?
>
> Right. Check the box 'use causal filter' when you run it.
>
> Makoto
>
>
> 2013/4/24 Marta Castellano <m at martacastellano.eu>
>
>> Dear eeglablist,
>>
>> I would need some help regarding the filtering of EEG data.
>>
>> I'm currently using the EEGlab 12.0.2.0b and filtering the data with
>> pop_eegfiltnew, which creates a type 1 windowed synch filter and the
>> filtering is implemented through firfirlt. As far as I understood, this
>> leads to a phase shift because of the firfilt, and also, given that the
>> impulse response of the filter is symetric, the filter is acausal (so that
>> no causal analysis can be performed).
>>
>> Does that means that, if i want to get a causal filter i should be using
>> the 'legacy' version of the pop_eegfilt that uses fir1 and firfirl to
>> filter the data?
>>
>> Thanks a lot in advance for your help,
>>
>> Marta
>>
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>
>
>
> --
> Makoto Miyakoshi
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
>
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