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diff --git a/help/en_US/scilab_en_US_help/sftrans.html b/help/en_US/scilab_en_US_help/sftrans.html deleted file mode 100644 index 1f67d6e..0000000 --- a/help/en_US/scilab_en_US_help/sftrans.html +++ /dev/null @@ -1,115 +0,0 @@ -<html><head> - <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> - <title>sftrans</title> - <style type="text/css" media="all"> - @import url("scilab_code.css"); - @import url("xml_code.css"); - @import url("c_code.css"); - @import url("style.css"); - </style> - </head> - <body> - <div class="manualnavbar"> - <table width="100%"><tr> - <td width="30%"> - <span class="previous"><a href="seqperiod.html"><< seqperiod</a></span> - - </td> - <td width="40%" class="center"> - <span class="top"><a href="section_e54aa8aac34aa55341e8b4b782fe1a74.html">FOSSEE Signal Processing Toolbox</a></span> - - </td> - <td width="30%" class="next"> - <span class="next"><a href="sgolay.html">sgolay >></a></span> - - </td> - </tr></table> - <hr /> - </div> - - - - <span class="path"><a href="index.html">FOSSEE Signal Processing Toolbox</a> >> <a href="section_e54aa8aac34aa55341e8b4b782fe1a74.html">FOSSEE Signal Processing Toolbox</a> > sftrans</span> - - <br /><br /> - <div class="refnamediv"><h1 class="refname">sftrans</h1> - <p class="refpurpose">Transform band edges of a generic lowpass filter (cutoff at W=1) represented in splane zero-pole-gain form.</p></div> - - -<div class="refsynopsisdiv"><h3 class="title">Calling Sequence</h3> - <div class="synopsis"><pre><span class="default">[</span><span class="default">Sz</span><span class="default">, </span><span class="default">Sp</span><span class="default">, </span><span class="default">Sg</span><span class="default">] = </span><span class="functionid">sftrans</span><span class="default"> (</span><span class="default">Sz</span><span class="default">, </span><span class="default">Sp</span><span class="default">, </span><span class="default">Sg</span><span class="default">, </span><span class="default">W</span><span class="default">, </span><span class="default">stop</span><span class="default">)</span> -<span class="default">[</span><span class="default">Sz</span><span class="default">, </span><span class="default">Sp</span><span class="default">] = </span><span class="functionid">sftrans</span><span class="default"> (</span><span class="default">Sz</span><span class="default">, </span><span class="default">Sp</span><span class="default">, </span><span class="default">Sg</span><span class="default">, </span><span class="default">W</span><span class="default">, </span><span class="default">stop</span><span class="default">)</span> -<span class="default">[</span><span class="default">Sz</span><span class="default">] = </span><span class="functionid">sftrans</span><span class="default"> (</span><span class="default">Sz</span><span class="default">, </span><span class="default">Sp</span><span class="default">, </span><span class="default">Sg</span><span class="default">, </span><span class="default">W</span><span class="default">, </span><span class="default">stop</span><span class="default">)</span></pre></div></div> - -<div class="refsection"><h3 class="title">Parameters</h3> - <dl><dt><span class="term">Sz:</span> - <dd><p class="para">Zeros.</p></dd></dt> - <dt><span class="term">Sp:</span> - <dd><p class="para">Poles.</p></dd></dt> - <dt><span class="term">Sg:</span> - <dd><p class="para">Gain.</p></dd></dt> - <dt><span class="term">W:</span> - <dd><p class="para">Edge of target filter.</p></dd></dt> - <dt><span class="term">stop:</span> - <dd><p class="para">True for high pass and band stop filters or false for low pass and band pass filters.</p></dd></dt></dl></div> - -<div class="refsection"><h3 class="title">Description</h3> - <p class="para">This is an Octave function. -Theory: Given a low pass filter represented by poles and zeros in the splane, you can convert it to a low pass, high pass, band pass or band stop by transforming each of the poles and zeros -individually. The following table summarizes the transformation:</p> - <p class="para">Transform Zero at x Pole at x ----------------- ------------------------- ------------------------ -Low Pass zero: Fc x/C pole: Fc x/C -S -> C S/Fc gain: C/Fc gain: Fc/C ----------------- ------------------------- ------------------------ -High Pass zero: Fc C/x pole: Fc C/x -S -> C Fc/S pole: 0 zero: 0 -gain: -x gain: -1/x ----------------- ------------------------- ------------------------ -Band Pass zero: b +- sqrt(b^2-FhFl) pole: b +- sqrt(b^2-FhFl) -S^2+FhFl pole: 0 zero: 0 -S -> C -------- gain: C/(Fh-Fl) gain: (Fh-Fl)/C -S(Fh-Fl) b=x/C (Fh-Fl)/2 b=x/C (Fh-Fl)/2 ----------------- ------------------------- ------------------------ -Band Stop zero: b +- sqrt(b^2-FhFl) pole: b +- sqrt(b^2-FhFl) -S(Fh-Fl) pole: +-sqrt(-FhFl) zero: +-sqrt(-FhFl) -S -> C -------- gain: -x gain: -1/x -S^2+FhFl b=C/x (Fh-Fl)/2 b=C/x (Fh-Fl)/2 ----------------- ------------------------- ------------------------ -Bilinear zero: (2+xT)/(2-xT) pole: (2+xT)/(2-xT) -2 z-1 pole: -1 zero: -1 -S -> - --- gain: (2-xT)/T gain: (2-xT)/T -T z+1 ----------------- ------------------------- ------------------------</p> - <p class="para">where C is the cutoff frequency of the initial lowpass filter, Fc is the edge of the target low/high pass filter and [Fl,Fh] are the edges of the target band pass/stop filter. With abundant tedious -algebra, you can derive the above formulae yourself by substituting the transform for S into H(S)=S-x for a zero at x or H(S)=1/(S-x) for a pole at x, and converting the result into the form:</p> - <p class="para">H(S)=g prod(S-Xi)/prod(S-Xj)</p></div> - -<div class="refsection"><h3 class="title">Examples</h3> - <div class="programlisting"><table border="0" width="100%"><tr><td width="98%"><pre class="scilabcode"><span class="scilabopenclose">[</span><span class="scilabid">Sz</span><span class="scilabdefault">,</span> <span class="scilabid">Sp</span><span class="scilabdefault">,</span> <span class="scilabid">Sg</span><span class="scilabopenclose">]</span> <span class="scilaboperator">=</span> <span class="scilabid">sftrans</span> <span class="scilabopenclose">(</span><span class="scilabnumber">5</span><span class="scilabdefault">,</span> <span class="scilabnumber">10</span><span class="scilabdefault">,</span> <span class="scilabnumber">15</span><span class="scilabdefault">,</span> <span class="scilabnumber">20</span><span class="scilabdefault">,</span> <span class="scilabnumber">30</span><span class="scilabopenclose">)</span> -<span class="scilabid">Sz</span> <span class="scilaboperator">=</span> <span class="scilabnumber">4</span> -<span class="scilabid">Sp</span> <span class="scilaboperator">=</span> <span class="scilabnumber">2</span> -<span class="scilabid">Sg</span> <span class="scilaboperator">=</span> <span class="scilabnumber">7.5000</span></pre></td><td valign="top"><a href="scilab://scilab.execexample/"><img src="ScilabExecute.png" border="0"/></a></td><td valign="top"><a href="scilab://scilab.editexample/"><img src="ScilabEdit.png" border="0"/></a></td><td></td></tr></table></div></div> - <br /> - - <div class="manualnavbar"> - <table width="100%"> - <tr><td colspan="3" class="next"><a href="http://bugzilla.scilab.org/enter_bug.cgi?product=Scilab%20software&component=Documentation%20pages" class="ulink">Report an issue</a></td></tr> -<tr> - <td width="30%"> - <span class="previous"><a href="seqperiod.html"><< seqperiod</a></span> - - </td> - <td width="40%" class="center"> - <span class="top"><a href="section_e54aa8aac34aa55341e8b4b782fe1a74.html">FOSSEE Signal Processing Toolbox</a></span> - - </td> - <td width="30%" class="next"> - <span class="next"><a href="sgolay.html">sgolay >></a></span> - - </td> - </tr></table> - <hr /> - </div> - </body> -</html> |