1 <?xml version="1.0" encoding="UTF-8"?>
2 <refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:svg="http://www.w3.org/2000/svg" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook" version="5.0-subset Scilab" xml:lang="en" xml:id="zpbutt">
4 <refname>zpbutt</refname>
5 <refpurpose> Butterworth analog filter</refpurpose>
8 <title>Calling Sequence</title>
9 <synopsis>[pols,gain]=zpbutt(n,omegac)</synopsis>
12 <title>Arguments</title>
17 <para>integer (filter order)</para>
23 <para>real (cut-off frequency in Hertz)</para>
29 <para>resulting poles of filter</para>
35 <para>resulting gain of filter</para>
41 <title>Description</title>
43 computes the poles of a Butterworth analog
44 filter of order <literal>n</literal> and cutoff frequency omegac
45 transfer function H(s) is calculated by <literal>H(s)=gain/real(poly(pols,'s'))</literal>
49 <title>Examples</title>
50 <programlisting role="example"><![CDATA[
53 [pols,gain]=zpbutt(n,omegac)