<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear all, <div><br></div><div>I'm doing frequency tagging on relatively short epochs. My frequency components are clearly there, but the signal-to-noise ratio is very low. In order to improve SNR, I want to try to concatenate the individual trials (with the appropriate epoch length to keep the frequency constant).</div><div><br></div><div>I simply concatenated all trial and timepoints vectors into a single trial structure, and I now have may data in a structure that has the following fields:</div><div> </div><div><br></div><div><div>appended = </div><div><br></div><div> label: {1x22 cell}</div><div> fsample: 512</div><div> elec: [1x1 struct]</div><div> trial: [22x157990 single]</div><div> time: [1x157990 double]</div><div><br></div><div><br></div></div><div>I then run the FFT below, and I get the following error:</div><div><br></div><div> error('the data does not contain a dimord, but it also does not resemble raw or component data');</div><div><br></div><div>Is it possible to run FFT on a single trial? Is there a way to work around this?</div><div><br></div><div>Best</div><div>Elisa</div><div><br></div><div><br></div><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Courier; ">cfg = [];</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Courier; ">cfg.output = <span style="color: #b101f0">'pow'</span>;</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Courier; ">cfg.channel = <span style="color: #b101f0">'all'</span>;</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Courier; ">cfg.method = <span style="color: #b101f0">'mtmfft'</span>;</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Courier; ">cfg.taper = <span style="color: #b101f0">'hanning'</span>;</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Courier; ">cfg.foi = 5:.5:35;</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Courier; color: rgb(57, 159, 51); "><span class="Apple-style-span" style="color: rgb(0, 0, 0); ">cfg.keeptrials = </span><span class="Apple-style-span" style="color: rgb(0, 0, 0); "><span style="color: #b101f0">'no'</span></span><span class="Apple-style-span" style="color: rgb(0, 0, 0); ">;</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Courier; color: rgb(57, 159, 51); "><span class="Apple-style-span" style="color: rgb(0, 0, 0); ">FFThann = ft_freqanalysis(cfg, epoched);</span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Courier; min-height: 14px; "><br></div></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Courier; min-height: 14px; "><br></div></body></html>