[FieldTrip] how does the time-window work

[Ivaylo Iotchev]

Thank you very much, I also realized that relatively late and should have
said something earlier, for others who might have been following this
topic. Indeed, I usually work with higher frequencies and did not realize
quickly enough that my time-window was too short for the 1 Hz target
frequency in my new study. I completely ignored that the segment was less
than a second, for which I feel a bit stupid, but I guess that happens at
30+ years. However, it is important to remind all other users: if you
choose a time-window larger than your segment you will not get an
error-message! The results will simply be empty.

Best wishes, everyone and thank you Dr. Schoffelen!

Am Do., 4. Aug. 2022 um 20:34 Uhr schrieb Schoffelen, J.M. (Jan Mathijs)
via fieldtrip <fieldtrip at science.ru.nl>:

> Hi Ivo,
>
> Please have a look at this FAQ:
> https://www.fieldtriptoolbox.org/faq/why_does_my_tfr_contain_nans/
>
> If your data segments are relatively short, asking for 7 cycles in the
> wavelet, might be too much. If your data segments are shorter than the
> length of the time window, no result will be computed.
>
> Solution: use longer data segments for your analysis.
>
> Best wishes,
>
> Jan-Mathijs
>
> > On 14 Jul 2022, at 14:11, Ivaylo Iotchev via fieldtrip <
> fieldtrip at science.ru.nl> wrote:
> >
> > Dear all,
> >
> > I am fairly new to the program fieldtrip and so far rather had used the
> classical "spectrogram" function for most of my time-frequency analyses. As
> I am now moving on to this advanced offer I am running up a curious
> difficulty, which might be in fact just a misunderstanding of how the
> program "speaks".
> >
> > In short, I seem to get results for lower frequencies (< 4 Hz) only with
> smaller time-windows, which is very counter-intuitive, but possibly this
> has to do with my reading of the lines.
> >
> > So far I assume that for
> > cfg.t_ftimwin (defining the time-window) the following line
> >
> > 7./cfg.foi, thus 7 cycles/time-window is the larger time-window compared
> to
> > 1./cfg.foi, i.e. 1 cycle/time-window
> >
> > Am I misunderstanding what is meant here by "cycle/window"? Or is this a
> mistake of specifying some properties of the data and/or method?
> >
> > Kind regards! And many thanks for your time if you have any :)
> >
> > Dr. Ivaylo (Ivo) Iotchev
> > _______________________________________________
> > fieldtrip mailing list
> > https://mailman.science.ru.nl/mailman/listinfo/fieldtrip
> >
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