<div dir="ltr">Dear Katharina,<div><br></div><div><div>> How exactly is the window size computed? In the archives I read a couple of times, that it should be close to <font color="#000000">1000/(lowest frequency) x (number of cycles). In my example that should lead to a window size of 600 and not 668. Where do those 'extra' 68 ms come from? </font></div><div><font color="#000000"><br></font></div><div><font color="#000000">I don't know this in detail, but the extra 68 ms must be for adjustments.</font></div><div><span style="color:rgb(0,0,0)"><br></span></div><div><font color="#000000">> How can I calculate how many cycles were used at specific frequencies? I have 3 cycles at the lowest and 14 cycles at the highest frequency and I am getting estimates for 28 frequencies. Does that mean that I get ~ 0.4 cycles more per frequency step? (3.4 cycles at 5.48 Hz; 3.8 cycles at 6.01 Hz)? </font></div></div><div class="gmail_extra"><br></div><div class="gmail_extra">If I use 'cycles', [3 0.85], 'freqs', [3 50], then the smallest number of cycles is 3 at 3Hz, and the largest number of cycles is something like 50 * (1-0.85) = 7.5 cycles at 50 Hz.</div><div class="gmail_extra"><br></div><div class="gmail_extra">Makoto</div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Nov 2, 2015 at 7:19 AM, Katharina Limbach <span dir="ltr"><<a href="mailto:katharina.limbach@uni-jena.de" target="_blank">katharina.limbach@uni-jena.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">Dear all,<div><br></div><div>I have two questions regarding the description of a time frequency analysis using the newtimef function.</div><div><br></div><div>This the is command that I am using:</div><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div><i>[ersp itc powbase times frequencies boot1 boot2 tfdata] = pop_newtimef( EEG, 1, chani, [-1460 596], [3 14] , 'baseline',[NaN], 'freqs', [5 60], 'plotitc' , 'off', 'plotersp', 'off', 'plotphase', 'off','freqscale', 'log', 'scale', 'abs', 'padratio', 1);</i></div><div><i><br></i></div></blockquote>Which leads to the following output in the Command window:<br><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div><div><i>Computing Event-Related Spectral Perturbation (ERSP) and</i></div></div><div><div><i> Inter-Trial Phase Coherence (ITC) images based on 1031 trials</i></div></div><div><div><i> of 514 frames sampled at 250 Hz.</i></div></div><div><div><i>Each trial contains samples from -1460 ms before to</i></div></div><div><div><i> 596 ms after the timelocking event.</i></div></div><div><div><i> Image frequency direction: normal</i></div></div><div><div><i>Using 3 cycles at lowest frequency to 14 at highest.</i></div></div><div><div><i>Generating 200 time points (-1125.3 to 261.3 ms)</i></div></div><div><div><i>Finding closest points for time variable</i></div></div><div><div><i>Time values for time/freq decomposition is not perfectly uniformly distributed</i></div></div><div><div><i>The window size used is 167 samples (668 ms) wide.</i></div></div><div><div><i>Estimating 28 log-spaced frequencies from 5.0 Hz to 60.0 Hz.</i></div></div><div><div><i>Processing time point (of 200): 10 20 30 40 50 60 70 80 90 100 110 120</i></div></div><div><div><i> 130 140 150 160 170 180 190 200</i></div></div><div><div><i>Computing the mean baseline spectrum</i></div></div><div><div><i>Note: Add output variables to command line call in history to</i></div></div><div><div><i> retrieve results and use the tftopo function to replot them</i></div></div></blockquote><div><br></div><div><div>How exactly is the window size computed? In the archives I read a couple of times, that it should be close to <font color="#000000">1000/(lowest frequency) x (number of cycles). In my example that should lead to a window size of 600 and not 668. Where do those 'extra' 68 ms come from? </font></div><div><span style="color:rgb(0,0,0)"><br></span></div><div><font color="#000000">How can I calculate how many cycles were used at specific frequencies? I have 3 cycles at the lowest and 14 cycles at the highest frequency and I am getting estimates for 28 frequencies. Does that mean that I get ~ 0.4 cycles more per frequency step? (3.4 cycles at 5.48 Hz; 3.8 cycles at 6.01 Hz)? </font></div><div><br></div><div>Thanks a lot for your help,</div><div>Katharina</div><div><br></div><div><span style="color:rgb(0,0,0)"><br></span></div><div><span style="color:rgb(0,0,0)"> </span></div></div><div><span style="color:rgb(0,0,0)"><br></span></div><div><br></div></div>
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