[Eeglablist] Enquiry regarding bandpass using eegfiltnew

[Delorme, Arnaud]

Dear Gladys,

If you want to high pass filter your data at say 1 Hz, then it means you want to let the high frequency "pass" above 1Hz. Your filter will have a lower edge below which the frequencies are filtered out (do not pass) and no higher edge.
So yes, high pass frequency filter have a lower edge and no upper edge.
Low pass frequency filter have an upper edge and no lower edge.

Best wishes,

Arno

> On Apr 6, 2020, at 12:56 PM, #HENG JIAMIN GLADYS# <JHENG007 at e.ntu.edu.sg> wrote:
> 
> Dear John,
> 
> Thanks for the reply. From the GUI, we need to input values for lower edge of the frequency pass band and higher edge of the frequency pass band.
> 
> From my understanding based on eegfiltnew help text, lower edge of frequency pass band corresponds to lowpass (which would be 30 Hz in my case), and higher edge of the frequency pass band corresponds to highpass (which would be 1 Hz in my case).
> 
> However, I also came across the youtube video of eeglab filtering (https://www.youtube.com/watch?v=nshi47blz7Q), at about 3:02 min, it was shown that the high-pass value of 0.5 Hz is input to "lower edge of the frequency pass band". My confusion is with this - shouldn't it be input under "higher edge of frequency pass band", or perhaps I have some misunderstanding of this function?
> 
> Dear Benedikt,
> 
> Thanks also for the recommendation of separating low and high-pass filter. By "the filter-order can then be different per filter", could I ask if there are recommended filter-order for each of the filters?
> 
> Regards,
> Gladys
> ________________________________
> From: John Johnson <john.johnson at gatech.edu>
> Sent: Monday, April 6, 2020 8:39 PM
> To: #HENG JIAMIN GLADYS# <JHENG007 at e.ntu.edu.sg>
> Cc: EEGLAB List <eeglablist at sccn.ucsd.edu>
> Subject: Re: [Eeglablist] Enquiry regarding bandpass using eegfiltnew
> 
> 
> Probably the easiest way is to use the EEGLAB GUI to filter a dataset, then use the eegh command to see how the call to pop_eegfiltnew was made.
> 
> Regards,
> John
> 
> On 4 Apr 2020, at 9:05, #HENG JIAMIN GLADYS# wrote:
> 
> Dear EEGlab list,
> 
> I would like to apply a 1 – 30 Hz bandpass filter on my data.
> 
> I am using the pop_eegfiltnew function, and would like to double-check if this code has the right input:
> EEG = pop_eegfiltnew(EEG, 30, 1, 660, 0, [], 1);
> 
> As the inputs are (EEG, locutoff, hicutoff, filtorder, revfilt, usefft, plotfreqz, minphase), therefore locutoff is “30” and hicutoff is “1”.
> 
> Thanks a lot in advance!
> 
> Stay safe and healthy,
> Gladys
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