scilab/modules/signal_processing/help/en_US/mese.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" xmlns:scilab="http://www.scilab.org" version="5.0-subset Scilab" xml:lang="en" xml:id="mese">
   3     <refnamediv>
   4         <refname>mese</refname>
   5         <refpurpose> maximum entropy spectral estimation</refpurpose>
   6     </refnamediv>
   7     <refsynopsisdiv>
   8         <title>Calling Sequence</title>
   9         <synopsis>[sm,fr]=mese(x [,npts]);</synopsis>
  10     </refsynopsisdiv>
  11     <refsection>
  12         <title>Arguments</title>
  13         <variablelist>
  14             <varlistentry>
  15                 <term>x</term>
  16                 <listitem>
  17                     <para>Input sampled data sequence</para>
  18                 </listitem>
  19             </varlistentry>
  20             <varlistentry>
  21                 <term>npts</term>
  22                 <listitem>
  23                     <para>
  24                         Optional parameter giving number of points of <literal>fr</literal> and <literal>sm</literal> (default is 256)
  25                     </para>
  26                 </listitem>
  27             </varlistentry>
  28             <varlistentry>
  29                 <term>sm</term>
  30                 <listitem>
  31                     <para>
  32                         Samples of spectral estimate on the frequency grid <literal>fr</literal>
  33                     </para>
  34                 </listitem>
  35             </varlistentry>
  36             <varlistentry>
  37                 <term>fr</term>
  38                 <listitem>
  39                     <para>
  40                         npts equally spaced frequency samples in <literal>[0,.5)</literal>
  41                     </para>
  42                 </listitem>
  43             </varlistentry>
  44         </variablelist>
  45     </refsection>
  46     <refsection>
  47         <title>Description</title>
  48         <para>
  49             Calculate the maximum entropy spectral estimate of <literal>x</literal>
  50         </para>
  51     </refsection>
  52     <refsection>
  53         <title>Sample</title>
  54         <scilab:image>
  55             rand("seed",12345),
  56             y = (0:10);
  57             x1 = sin(2*%pi*y/20);
  58             x2 = sin(3.5*%pi*y/20);
  59             w = .4*(rand(y)-.5*ones(y));
  60             x = x1+2*x2+w;
  61             [sm,fr1] = mese(x,10)
  62             function [xm,fr] = bt(x)
  63             xsize = max(size(x))
  64             [xf,fr] = frmag(x,256)
  65             xm = xf.*conj(xf)/xsize
  66             endfunction
  67             [xm,fr] = bt(x);
  68             scf();
  69             subplot(3,1,1);
  70             plot(x);
  71             subplot(3,1,2);
  72             plot(fr1,sm)
  73             subplot(3,1,3);
  74             plot(fr,xm)
  75         </scilab:image>
  76     </refsection>
  77
  78     <refsection>
  79         <title>Examples</title>
  80         <programlisting role="example"><![CDATA[
  81 rand("seed",12345),
  82 y = (0:10);
  83 x1 = sin(2*%pi*y/20);
  84 x2 = sin(3.5*%pi*y/20);
  85 w = .4*(rand(y)-.5*ones(y));
  86 x = x1+2*x2+w;
  87 [sm,fr1] = mese(x,10)
  88 // Define macro which computes the
  89 // Blackman-Tukey periodogram
  90 function [xm,fr] = bt(x)
  91   xsize = max(size(x))
  92   [xf,fr] = frmag(x,256)
  93   xm = xf.*conj(xf)/xsize
  94 endfunction
  95 [xm,fr] = bt(x);
  96 scf();
  97 subplot(3,1,1);
  98 plot(x);
  99 subplot(3,1,2);
 100 plot(fr1,sm)
 101 subplot(3,1,3);
 102 plot(fr,xm)
 103  ]]></programlisting>
 104     </refsection>
 105 </refentry>