<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><font class="Apple-style-span" face="Arial">Hi Tadeusz,</font></div><div><font class="Apple-style-span" face="Arial"><br></font></div><div><font class="Apple-style-span" face="Arial">I forward the reply to your question to this forum, because other people may benefit from the discussion. Also, for future questions, it would be good if you directed any question to this list. Everybody can participate in the discussion, increasing the odds for its resolution. Also, in general, when posting a question it would be good to provide as many details as possible (with respect to matlab version, fieldtrip version etc, but also with for example relevant screen dumps).</font></div><div><font class="Apple-style-span" face="Arial"><br></font></div><div><font class="Apple-style-span" face="Arial">As to your question, p</font><span class="Apple-style-span" style="font-family: Arial; ">lease have a look at the pasted matlab-code and attached figure below. In short, I tried to reproduce your problem, but I fail to do so (because the blue and red lines look different enough). Be sure that you use an up-to-date version of FieldTrip. I remember that there have been some problems with filtering in the past, but these have been resolved quite some time ago (at least > 0.5 year or even longer).</span></div><div><font class="Apple-style-span" face="Arial"><br></font></div><div><font class="Apple-style-span" face="Arial">Best wishes,</font></div><div><font class="Apple-style-span" face="Arial"><br></font></div><div><font class="Apple-style-span" face="Arial">Jan-Mathijs</font></div><div><font class="Apple-style-span" face="Arial"><br></font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier">>> data = [];</font></div><div><font class="Apple-style-span" face="Courier">>> data.trial{1} = randn(1,10000);</font></div><div><font class="Apple-style-span" face="Courier">>> data.time{1} = (0:9999)/1000;</font></div><div><font class="Apple-style-span" face="Courier">>> data.fsample = 1000;</font></div><div><font class="Apple-style-span" face="Courier">>> data.label = {'1'};</font></div><div><font class="Apple-style-span" face="Courier">>> cfg = [];</font></div><div><font class="Apple-style-span" face="Courier">>> cfg.bpfilter = 'yes';</font></div><div><font class="Apple-style-span" face="Courier">>> cfg.bpfreq = [0.01 0.2];</font></div><div><font class="Apple-style-span" face="Courier">>> cfg.bpfilttype = 'fir';</font></div><div><font class="Apple-style-span" face="Courier">>> datafilt = ft_preprocessing(cfg, data);</font></div><div><font class="Apple-style-span" face="Courier">Warning: the data does not contain a trial definition </font></div><div><font class="Apple-style-span" face="Courier">> In utilities/private/warning_once at 81</font></div><div><font class="Apple-style-span" face="Courier"> In utilities/private/fixsampleinfo at 51</font></div><div><font class="Apple-style-span" face="Courier"> In ft_datatype_raw at 95</font></div><div><font class="Apple-style-span" face="Courier"> In ft_checkdata at 170</font></div><div><font class="Apple-style-span" face="Courier"> In ft_preprocessing at 284</font></div><div><font class="Apple-style-span" face="Courier">Warning: reconstructing sampleinfo by assuming that the trials are consecutive</font></div><div><font class="Apple-style-span" face="Courier">segments of a continuous recording </font></div><div><font class="Apple-style-span" face="Courier">> In utilities/private/warning_once at 81</font></div><div><font class="Apple-style-span" face="Courier"> In utilities/private/fixsampleinfo at 64</font></div><div><font class="Apple-style-span" face="Courier"> In ft_datatype_raw at 95</font></div><div><font class="Apple-style-span" face="Courier"> In ft_checkdata at 170</font></div><div><font class="Apple-style-span" face="Courier"> In ft_preprocessing at 284</font></div><div><font class="Apple-style-span" face="Courier">preprocessing</font></div><div><font class="Apple-style-span" face="Courier">preprocessing trial 1 from 1</font></div><div><font class="Apple-style-span" face="Courier">the call to "ft_preprocessing" took 1 seconds and an estimated 8 MB</font></div><div><font class="Apple-style-span" face="Courier">>> figure;plot(data.trial{1});hold on;plot(datafilt.trial{1},'r');</font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier"><img height="419" width="559" apple-width="yes" apple-height="yes" id="5dffdd9f-98e7-4ba2-a5c6-744b44eaa9cd" src="cid:0B6427E6-3838-4BF0-9D29-AFB130055DAC"></font></div><div><font class="Apple-style-span" face="Courier"> </font></div><div><br><div>Begin forwarded message:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1);"><b>From: </b></span><span style="font-family:'Helvetica'; font-size:medium;">"T.W. Kononowicz" <<a href="mailto:t.w.kononowicz@gmail.com">t.w.kononowicz@gmail.com</a>><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1);"><b>Date: </b></span><span style="font-family:'Helvetica'; font-size:medium;">September 9, 2011 3:01:07 PM GMT+02:00<br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1);"><b>To: </b></span><span style="font-family:'Helvetica'; font-size:medium;"><<a href="mailto:jan.schoffelen@donders.ru.nl">jan.schoffelen@donders.ru.nl</a>><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1);"><b>Subject: </b></span><span style="font-family:'Helvetica'; font-size:medium;"><b>Filtering</b><br></span></div><br><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; color: rgb(0, 0, 128); font-size: 12px; font-family: Cambria, sans-serif; "><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">Dear Prof. Schoffelen,</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">I am trying to filter continuous data using the following code. However, this procedure doesn't affect the data at all. It looks similarly for low and high pass filtering options. I am really puzzled what could go wrong here. Any suggestions? <span class="Apple-style-span" style="font-size: 12px; font-family: Cambria, sans-serif; "> </span></div><div><div><div><font class="Apple-style-span" face="'Lucida Grande'" size="3"><span class="Apple-style-span" style="font-size: 13px;"><font class="Apple-style-span" face="Cambria,sans-serif" size="3"><span class="Apple-style-span" style="font-size: 12px;"><br></span></font></span></font></div></div></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">cfg = [];</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">cfg.dataset = <span style="color: #b132f3">'01_21_mRef.vhdr'</span>;</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">chans = {<span style="color: #b132f3">'FCz'</span> <span style="color: #b132f3">'Cz'</span> <span style="color: #b132f3">'Fz'</span>};</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">cfg.channel = chans;</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">cfg.bpfilter = <span style="color: #b132f3">'yes'</span>;</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">cfg.bpfilttype = <span style="color: #b132f3">'fir'</span>;</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">cfg.bpfreq = [0.01 0.2];</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">data = ft_preprocessing(cfg);</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; ">Thank you in advance,</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 13px/normal 'Lucida Grande'; "><br></div><p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 13.0px 'Lucida Grande'"></p><div><div><font class="Apple-style-span" color="rgb(0, 0, 128)"><font class="Apple-style-span" face="Cambria"><span class="Apple-style-span" style="font-size: 12px; ">Tadeusz Kononowicz</span></font></font></div><div><font class="Apple-style-span" color="rgb(0, 0, 128)"><font class="Apple-style-span" face="Cambria"><span class="Apple-style-span" style="font-size: 12px;">University of Groningen, Experimental Psychology</span></font></font></div></div><div><br class="webkit-block-placeholder"></div></div><div><br></div></div>
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<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Jan-Mathijs Schoffelen, MD PhD </div><div>Donders Institute for Brain, Cognition and Behaviour, <br>Centre for Cognitive Neuroimaging,<br>Radboud University Nijmegen, The Netherlands</div><div><a href="mailto:J.Schoffelen@donders.ru.nl">J.Schoffelen@donders.ru.nl</a></div><div>Telephone: +31-24-3614793</div></div></span></div></span></div></span></span>
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