<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi Alessandro, <div class=""><br class=""></div><div class="">any defaults are set in the low-level functions that ft_preprocessing calls. So, for the lowpass filter, go have a look at the help of ft_preproc_lowpassfilter.m, it says:</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">% FT_PREPROC_LOWPASSFILTER applies a low-pass filter to the data and thereby</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">% removes all high frequency components </span><span style="font-variant-ligatures: no-common-ligatures;" class="">in</span><span style="font-variant-ligatures: no-common-ligatures" class=""> the data</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">%</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">% Use as</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">%   [filt] = ft_preproc_lowpassfilter(dat, Fsample, Flp, N, type, dir, instabilityfix)</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">% where</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">%   dat        data matrix (Nchans X Ntime)</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">%   Fsample    sampling frequency </span><span style="font-variant-ligatures: no-common-ligatures;" class="">in</span><span style="font-variant-ligatures: no-common-ligatures" class=""> Hz</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">%   Flp        filter frequency</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">%   N          optional filter order, </span><span style="font-variant-ligatures: no-common-ligatures;" class="">default</span><span style="font-variant-ligatures: no-common-ligatures" class=""> is </span><span style="font-variant-ligatures: no-common-ligatures;" class="">6</span><span style="font-variant-ligatures: no-common-ligatures" class=""> (but) or dependent upon</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class="">%              frequency band and data length (fir/firls)</span></div></div><div class="">etc...</div><div class=""><br class=""></div><div class="">The default for the Butterworth low-pass filter is thus 6 (for the bandpass it’s 4). You can set your preferred order when calling ft_preprocessing.m e.g. via cfg.lpfiltord = 4 or whatever makes sense.</div><div class=""><br class=""></div><div class="">Hope that helps</div><div class=""><br class=""></div><div class="">Eugenio</div><div class=""><br class=""></div><div class=""><div><div class="">On 16 Oct 2018, at 21:56, Alessandro Orticoni <<a href="mailto:alessandro.orticoni@gmail.com" class="">alessandro.orticoni@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Dear all,<div class=""><br class=""></div><div class="">I would like to ask you just a question: which is the default order of the filters implemented by ft_preprocessing? I cannot find it anywhere.</div><div class=""><br class=""></div><div class="">Thanks a lot,</div><div class="">Alessandro Orticoni </div></div>
_______________________________________________<br class="">fieldtrip mailing list<br class=""><a href="https://mailman.science.ru.nl/mailman/listinfo/fieldtrip" class="">https://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a><br class="">https://doi.org/10.1371/journal.pcbi.1002202<br class=""></div></div><br class=""></div></body></html>