fc763c29e31cb09ea977e778c52b06889d3b8297
[scilab.git] / scilab / modules / signal_processing / help / en_US / zpbutt.xml
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">
3   <refnamediv>
4     <refname>zpbutt</refname>
5     <refpurpose> Butterworth analog filter</refpurpose>
6   </refnamediv>
7   <refsynopsisdiv>
8     <title>Calling Sequence</title>
9     <synopsis>[pols,gain]=zpbutt(n,omegac)</synopsis>
10   </refsynopsisdiv>
11   <refsection>
12     <title>Arguments</title>
13     <variablelist>
14       <varlistentry>
15         <term>n</term>
16         <listitem>
17           <para>integer (filter order)</para>
18         </listitem>
19       </varlistentry>
20       <varlistentry>
21         <term>omegac</term>
22         <listitem>
23           <para>real (cut-off frequency in Hertz)</para>
24         </listitem>
25       </varlistentry>
26       <varlistentry>
27         <term>pols</term>
28         <listitem>
29           <para>resulting poles of filter</para>
30         </listitem>
31       </varlistentry>
32       <varlistentry>
33         <term>gain</term>
34         <listitem>
35           <para>resulting gain of filter</para>
36         </listitem>
37       </varlistentry>
38     </variablelist>
39   </refsection>
40   <refsection>
41     <title>Description</title>
42     <para>
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>
46     </para>
47   </refsection>
48 </refentry>