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<span class="path"><a href="index.html">FOSSEE Signal Processing Toolbox</a> >> <a href="section_cc2bc01c47967d47fcf3507a91d572ba.html">FOSSEE Signal Processing Toolbox</a> > impzlength</span>
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<div class="refnamediv"><h1 class="refname">impzlength</h1>
<p class="refpurpose">Impulse response length</p></div>
<div class="refsynopsisdiv"><h3 class="title">Calling Sequence</h3>
<div class="synopsis"><pre><span class="default">len</span><span class="default"> = </span><span class="functionid">impzlength</span><span class="default">(</span><span class="default">b</span><span class="default">, </span><span class="default">a</span><span class="default">, </span><span class="default">tol</span><span class="default">)</span>
<span class="default">returns</span> <span class="default">the</span> <span class="default">impulse</span> <span class="default">response</span> <span class="default">length</span> <span class="default">for</span> <span class="default">the</span> <span class="default">causal</span> <span class="default">discrete</span><span class="default">-</span><span class="default">time</span> <span class="default">filter</span>
<span class="default">with</span> <span class="default">the</span> <span class="default">transfer</span> <span class="default">function</span> <span class="default">coefficients</span> <span class="default">for</span> <span class="default">numerator</span> <span class="default">and</span> <span class="default">denominator</span> <span class="default">in</span>
<span class="default">a</span> <span class="default">and</span> <span class="default">b</span> <span class="default">respectively</span><span class="default">. </span><span class="default">For</span> <span class="default">stable</span> <span class="default">IIR</span> <span class="default">filters</span><span class="default">, </span><span class="default">len</span> <span class="default">is</span> <span class="default">the</span> <span class="default">effective</span> <span class="default">length</span>
<span class="default">impulse</span> <span class="default">response</span> <span class="default">length</span><span class="default">, </span><span class="default">i</span><span class="default">.</span><span class="default">e</span><span class="default">. </span><span class="default">the</span> <span class="default">length</span> <span class="default">after</span> <span class="default">which</span> <span class="default">the</span> <span class="default">response</span> <span class="default">is</span>
<span class="default">essentially</span> <span class="default">zero</span>
<span class="default">len</span><span class="default"> = </span><span class="functionid">impzlength</span><span class="default">(</span><span class="default">sos</span><span class="default">)</span>
<span class="default">returns</span> <span class="default">the</span> <span class="default">impulse</span> <span class="default">response</span> <span class="default">length</span> <span class="default">of</span> <span class="default">the</span> <span class="default">filter</span> <span class="default">specified</span> <span class="default">by</span> <span class="default">second</span>
<span class="default">order</span> <span class="default">sections</span> <span class="default">matrix</span><span class="default">. </span><span class="default">sos</span> <span class="default">is</span> <span class="default">a</span> <span class="default">Kx6</span> <span class="default">matrix</span><span class="default">, </span><span class="default">where</span> <span class="default">K</span> <span class="default">is</span> <span class="default">the</span> <span class="default">number</span> <span class="default">of</span>
<span class="default">sections</span><span class="default">. </span><span class="default">Each</span> <span class="default">row</span> <span class="default">of</span> <span class="default">the</span> <span class="default">sos</span> <span class="default">matrix</span> <span class="default">corresponds</span> <span class="default">to</span> <span class="default">a</span> <span class="default">second</span> <span class="default">order</span>
<span class="default">biquad</span> <span class="default">filter</span>
<span class="default">len</span><span class="default"> = </span><span class="functionid">impzlength</span><span class="default">(</span><span class="default">__</span><span class="default">, </span><span class="default">tol</span><span class="default">)</span>
<span class="default">specifies</span> <span class="default">a</span> <span class="default">tolerance</span> <span class="default">for</span> <span class="default">estimating</span> <span class="default">the</span> <span class="default">effective</span> <span class="default">impulse</span> <span class="default">response</span>
<span class="default">length</span> <span class="default">in</span> <span class="default">case</span> <span class="default">of</span> <span class="default">an</span> <span class="default">IIR</span> <span class="default">filter</span><span class="default">. </span><span class="default">By</span> <span class="default">default</span><span class="default">, </span><span class="default">tol</span> <span class="default">is</span><span class="default"> 5</span><span class="default">e</span><span class="default">-5. </span><span class="default">Increasing</span> <span class="default">tol</span>
<span class="default">leads</span> <span class="default">to</span> <span class="default">shorter</span> <span class="default">len</span> <span class="default">and</span> <span class="default">vice</span><span class="default">-</span><span class="default">versa</span></pre></div></div>
<div class="refsection"><h3 class="title">Parameters</h3>
<dl></dl></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="scilabnumber">1</span><span class="scilabopenclose">)</span> <span class="scilabid">Low</span> <span class="scilabid">pass</span> <span class="scilabid">IIR</span> <a class="scilabmacro" href="scilab://filter">filter</a> <span class="scilabstring">with</span> <span class="scilabstring">pole</span> <span class="scilabstring">at</span> <span class="scilabstring">0.9</span>
<span class="scilabid">b</span> <span class="scilaboperator">=</span> <span class="scilabnumber">1</span><span class="scilabdefault">;</span>
<span class="scilabid">a</span> <span class="scilaboperator">=</span> <span class="scilabopenclose">[</span><span class="scilabnumber">1</span> <span class="scilaboperator">-</span><span class="scilabnumber">0.9</span><span class="scilabopenclose">]</span><span class="scilabdefault">;</span>
<span class="scilabid">len</span> <span class="scilaboperator">=</span> <span class="scilabid">impzlength</span><span class="scilabopenclose">(</span><span class="scilabid">b</span><span class="scilabdefault">,</span><span class="scilabid">a</span><span class="scilabopenclose">)</span><span class="scilabdefault">;</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>
<div class="refsection"><h3 class="title">See also</h3>
<ul class="itemizedlist"><li class="member"><a href="scilab://designfilt" class="link">| digitalFilter | impz | zp2sos</a></li></ul></div>
<div class="refsection"><h3 class="title">Authors</h3>
<ul class="itemizedlist"><li class="member">Ayush Baid</li></ul></div>
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