[Eeglablist] window length and stepsize for short-time FFTs

[Makoto Miyakoshi]

Dear Joshua

Sorry for belated response.

> For the higher frequencies, does the window length change?

If 'cycle', 0 means to use short-term Fourier Transform (STFT), the window
size should be constant across frequency bins by definition.

>  As for the step size, is that determined by the timesout parameter?

I think so. In STFT, step size can be determined as you like.

Makoto


On Mon, Feb 20, 2017 at 4:06 AM, Baker, Joshua <joshua.baker at ntu.ac.uk>
wrote:

> Dear list,
>
>
>
> When using the newtimef function and defining cycles as ‘0’, it is my
> understanding that a constant window (zero-padded) is used over all
> frequencies. I see that there is an optional parameter for defining window
> size, but when you do not specify this, how does EEGlab calculate the
> window size and also the step size? E.g. if I were to define:
>
>
>
> [..]= newtimef(myTrials(1,:,:),EEG.pnts, [-500 1500], EEG.srate, 0,'freqs',[1
> 45],'nfreqs',100,'timesout',300,'padratio',8); %where EEG.srate=256
>
>
>
> Given I require activity at 1Hz, then I would necessarily require a window
> length of at least 1000ms. For the higher frequencies, does the window
> length change? As for the step size, is that determined by the timesout
> parameter?
>
>
>
> Many thanks for your time.
>
>
>
> Joshua Baker
>
> Psychology Technician (Behavioural Neuroscience)
>
> Taylor 001
>
> Department of Psychology
>
> Nottingham Trent University
>
>
>
> https://uk.linkedin.com/in/joshua-baker-81562627
>
>
>
> https://myntuac.sharepoint.com/sites/pts/SitePages/Home.aspx
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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