[Eeglablist] frames and epochlim in newtimef

[Archana Singh]

Hi,

I wonder if there there were any responses to this question, which came in
my search on how to specify 'epochlim'  in newtimef().
I am also trying to figure if I could extract only a part of the epoch for
the TF decomposition, something like what is done by 'tlimits' in
pop_newtimef() function.

According to the help document of newtimef() epochlim (see below),  I must
specify the epoch time range of the original epoched data. I have 3D inuput
data : Sub x Time x Trial. Am I right?
Thanks for your suggestions if you have any.

% epochlim = [mintime maxtime] (ms). Note that these are the time limits

%                     of the data epochs themselves, NOT A SUB-WINDOW
TO EXTRACT
%                     FROM THE EPOCHS as is the case for
pop_newtimef(). {[-1000 2000]}



Archana


On Fri, Aug 22, 2014 at 12:10 AM, Omar Mian <omian88 at gmail.com> wrote:

> Hi,
>
> I'm having a bit of difficulty fully understanding the use of 'frames' and
> 'epochlim' in newtimef.
>
> My assumption is that frames should always equal
> length([epochlim(1):1000/srate:epochlim(2)])
> I haven't looked through the newtimef code, but I assume this would be
> necessary to properly define the location of the zero time (time locking
> event) within the epoch.
>
> If my assumption is correct, I have two main points of confusion.
>
> 1. The documentation states that 'frames' is ignored for 2D and 3D data (I
> assume because frames should now be defined by the dimensions of the
> array). However, this does not seem to be the case. The following two
> segments of code (differing only in the frames parameter) produce different
> output frequency bins, even though they both use 2D data with the same
> dimensions.
>
> cycles = 0; currsig = rand(2001,5); frames = 2001; epochlim = [-1000
> 1000]; srate = 1000;
> [ersp,itc,powbase,times,freqs]=
> newtimef(currsig,frames,epochlim,srate,cycles);
>
> cycles = 0; currsig = rand(2001,5); frames = 501; epochlim = [-1000 1000];
> srate = 1000;
> [ersp,itc,powbase,times,freqs]=
> newtimef(currsig,frames,epochlim,srate,cycles);
>
>
> 2. If I specify an epochlim that has a time range smaller than the epoch,
> newtimef still runs without producing an error. But in this case, how does
> it know where the time locking event is within the epoch?
>
> cycles = 0; currsig = rand(2001,5); frames = 2000; epochlim = [-500 500];
> srate = 1000;
> [ersp,itc,powbase,times,freqs]=
> newtimef(currsig,frames,epochlim,srate,cycles);
>
> Can anyone clarify these issues for me?
>
> Thanks
>
> Omar
>
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