<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial,helvetica,sans-serif;font-size:10pt">Hi Anders,<br><br>Can you please double check the semicolon on the function y definition? You also have a f1 and f2 but only f1 is defined..<br><br>Regards,<br><br><br>Julio Gonzalez-Saenz<br>www.part-time-scientists.com<br>www.neex-technologies.com<br><div><br></div><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font size="2" face="Tahoma"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Anders Sneckenborg <anders@simbalsyd.se><br><b><span style="font-weight: bold;">To:</span></b> "users@lists.scilab.org" <users@lists.scilab.org><br><b><span style="font-weight: bold;">Sent:</span></b> Wed, 14 April, 2010 22:19:29<br><b><span style="font-weight: bold;">Subject:</span></b>
[scilab-Users] lowpassfilter <br></font><br>
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<p class="MsoNormal">Hi</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"><span lang="EN-US">When running the following script I expected
the filtered signal to have an amplitude of 0.5. </span></p>
<p class="MsoNormal"><span lang="EN-US">My intention was to lowpassfilter a signal
with the same frequency as the cutoff frequency. Am I doing something wrong? </span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">//---------------------------</span></p>
<p class="MsoNormal"><span lang="EN-US">f1 = 0.1; //Hz</span></p>
<p class="MsoNormal"><span lang="EN-US">tSamp = 0.01; //s</span></p>
<p class="MsoNormal"><span lang="EN-US">tMax = 200;</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal">t = 0:tSamp:tMax;</p>
<p class="MsoNormal">y = 1*sin(2*%pi*f1*t); + 0.5*sin(2*%pi*f2*t);</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Order = 1;</p>
<p class="MsoNormal">Fcutoff = 0.1;</p>
<p class="MsoNormal">Fs = 1/tSamp;</p>
<p class="MsoNormal">hz = iir(Order,'lp','butt',[Fcutoff/Fs 0],[0 0]);</p>
<p class="MsoNormal"><span lang="EN-US">sl = tf2ss(hz);</span></p>
<p class="MsoNormal"><span lang="EN-US">yf = flts(y,sl);</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">plot(t,y,'-b');</span></p>
<p class="MsoNormal"><span lang="EN-US">plot(t,yf,'-r');</span></p>
<p class="MsoNormal"><span lang="EN-US">//---------------------------</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">Best regards</span></p>
<p class="MsoNormal"><span lang="EN-US">Anders</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
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