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<div dir="ltr" data-setdir="false">Hi Helena,</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">The warning probably means that the time points you are specifying in cfg.toi do not fully match those present in your data. Try giving a real time interval extracted from your variable time inside stim. <br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">You should get an output of time-frequency bins centered at each toi you specify. However, some time-frequency bins at the edges are missing due to the "boundary effects". I recommend you to check the time frequency tutorial <a href="https://www.fieldtriptoolbox.org/tutorial/timefrequencyanalysis/" rel="nofollow" target="_blank" class="enhancr_card_4387069240">Time-frequency analysis using Hanning window, multitapers and wavelets - FieldTrip toolbox</a></div><div><br></div><div id="ydp29443421enhancr_card_4387069240" class="ydp29443421yahoo-link-enhancr-card ydp29443421ymail-preserve-class ydp29443421ymail-preserve-style" style="max-width:400px;font-family:YahooSans, Helvetica Neue, Segoe UI, Helvetica, Arial, sans-serif" data-url="https://www.fieldtriptoolbox.org/tutorial/timefrequencyanalysis/" data-type="YENHANCER" data-size="MEDIUM" contenteditable="false"><a href="https://www.fieldtriptoolbox.org/tutorial/timefrequencyanalysis/" style="text-decoration-line: none !important; text-decoration-style: solid !important; text-decoration-color: currentcolor !important; color: rgb(0, 0, 0) !important;" class="ydp29443421yahoo-enhancr-cardlink" rel="nofollow" target="_blank"><table class="ydp29443421card-wrapper ydp29443421yahoo-ignore-table" style="max-width:400px" cellspacing="0" cellpadding="0" border="0"><tbody><tr><td width="400"><table class="ydp29443421card ydp29443421yahoo-ignore-table" style="max-width:400px;border-width:1px;border-style:solid;border-color:rgb(224, 228, 233);border-radius:2px" width="100%" cellspacing="0" cellpadding="0" border="0"><tbody><tr><td class="ydp29443421card-primary-image-cell" style="background-color: rgb(0, 0, 0); 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background-repeat: repeat; background-attachment: scroll; background-image: none; background-size: auto; position: relative; z-index: 2; width: 100%; max-width: 400px; border-radius: 0px 0px 2px 2px; border-top: 1px solid rgb(224, 228, 233);" cellspacing="0" cellpadding="0" border="0" align="center"><tbody><tr><td style="background-color:#ffffff;padding:16px 0 16px 12px;vertical-align:top;border-radius:0 0 0 2px"></td><td style="vertical-align:middle;padding:12px 24px 16px 12px;width:99%;font-family:YahooSans, Helvetica Neue, Segoe UI, Helvetica, Arial, sans-serif;border-radius:0 0 2px 0"><h2 class="ydp29443421card-title" style="font-size: 14px; line-height: 19px; margin: 0px 0px 6px; font-family: YahooSans, Helvetica Neue, Segoe UI, Helvetica, Arial, sans-serif; color: rgb(38, 40, 42); max-width: 314px;">Time-frequency analysis using Hanning window, multitapers and wavelets -...</h2><p class="ydp29443421card-description" style="font-size: 12px; line-height: 16px; margin: 0px; color: rgb(151, 155, 167);"></p></td></tr></tbody></table></td></tr></tbody></table></td></tr></tbody></table></a></div></div><div class="ydp99c9848byahoo-style-wrap" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 13px;"><div dir="ltr" data-setdir="false">Best wishes,</div><div dir="ltr" data-setdir="false">Maite<br></div><div><br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><br></div></div><div id="yahoo_quoted_4271329758" class="yahoo_quoted">
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En viernes, 23 de octubre de 2020 9:31:25 GMT+1, Helena Pereira <hri.pereira@campus.fct.unl.pt> escribió:
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<div><div id="yiv7751115327"><div dir="ltr"><div>Dear FieldTrip community, <br></div><div><br></div><div>I am a beginner using fieldtrip, so I know I am missing something in this domain:<br></div><div>I am making a time-frequency analysis of EEG data with wavelets. However, I am getting the following warning:<br></div><div><i><br></i></div><div><i>Warning: output time-bins artrial 30, frequency 4 (7.00 Hz)</i></div><div><i>Warning: output time-bins are different from input time-bins</i></div><div><i><br></i></div><div>Using this parameters:</div><div><span style="font-family:monospace;"> % Wavelet power<br> cfg = []<br> cfg.output = 'pow';<br> cfg.channel = [1:64];<br> cfg.keeptrials='no';<br> cfg.method = 'wavelet';<br> cfg.width = 7;<br> cfg.toi = -2.0:0.01:2.0;<br> cfg.foi = 4:1:20;</span></div><div><span style="font-family:monospace;"><br></span></div><div><span style="font-family:monospace;"> p_stim = ft_freqanalysis(cfg,stim);</span></div><div><br></div><div>I can mitigate the warning by changing the cfg.toi from <span style="font-family:monospace;">[ -2.0:0.01:2.0] <span style="font-family:arial, sans-serif;">to
</span>[ -2.0:0.5:2.0]
</span></div><div><br></div><div>However, the plot of the spectrum changes a lot, as I expected as the time window changes from intervals from 0.01 to 0.5:</div><div>With the warning:</div><div><div><div><img src="cid:2v1O2vd87hDAekRjy8pD" yahoo_partid="1.3" alt="imagem.png" width="492" height="281"><br></div></div></div><div><br></div><div>Without the warning:</div><div><br></div><div>
<img src="cid:EOcbwz5bn19qL869U0Ke" alt="imagem.png" width="492" height="271">
</div><div><br></div><div><br></div><div>I know I am missing something regarding signal analysis... Why the differences in the changing the step of the interval leads to the warning?<br></div><div><br></div><div>Can you help me? I am not sure if the warning can influence the final results. <br></div><div><br></div><div>Best regards, <br></div><div>Helena Pereira<br></div><div><br></div><div><i></i></div></div></div>_______________________________________________<br>fieldtrip mailing list<br><a href="https://mailman.science.ru.nl/mailman/listinfo/fieldtrip" target="_blank">https://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a><br><a href="https://doi.org/10.1371/journal.pcbi.1002202" target="_blank">https://doi.org/10.1371/journal.pcbi.1002202</a><br></div>
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