<body><html><body><div dir="auto">Dear Chengyuan Wu,</div><div dir="auto"><br></div><div dir="auto">I think the easiest way to fix this issue would be to include more data in the time-frequency calculation, i.e., a longer time interval to avoid cutting of the tf calculation right at the timepoints that you want to analyze<span style="font-size: 12pt;">. This way, the NaN would appear outside of your time window of interest. Would this be possible?</span></div><div dir="auto"><br></div><div dir="auto">Best,</div><div dir="auto">Enya</div></body></html><div><br></div><div id="ms-outlook-mobile-signature" dir="auto">Get <a href="https://aka.ms/AAb9ysg">Outlook for Android</a></div></body>