<?xml version="1.0" encoding='utf-8'?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml">
<wml>
<card id="card1" title="Butterworth filter - Page 4 - Wikipedia">
<p>
<a accesskey="1" href="page.php?w=Butterworth_filter&amp;p=3">1.Previous</a><br />
<a accesskey="3" href="page.php?w=Butterworth_filter&amp;p=5">3.Next</a>
</p>
<p>in radians per second and  is the number of <a href="page.php?w=Pole_%28complex_analysis%29">pole</a>s in the filter--equal to the number of reactive elements in a passive filter. Its <a href="page.php?w=cutoff_frequency">cutoff frequency</a> (the <a href="page.php?w=Cutoff_frequency">half-power point</a> of approximately &minus;3 <a href="page.php?w=decibel">dB</a> or a voltage gain of 1/&nbsp;? 0.7071) is normalized to ? = 1 radian per second. Butterworth only dealt with filters with an even number of poles in his paper, though odd-order filters</p><p>
<a accesskey="1" href="page.php?w=Butterworth_filter&amp;p=3">1.Previous</a><br />
<a accesskey="3" href="page.php?w=Butterworth_filter&amp;p=5">3.Next</a>
</p>

<do type="prev" label="Search">
        <go href="search.wml"/>
</do>

</card>
</wml>
