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="wigner">
4 <refname>wigner</refname>
5 <refpurpose> 'time-frequency' wigner spectrum</refpurpose>
8 <title>Calling Sequence</title>
9 <synopsis>[tab]=wigner(x,h,deltat,zp)</synopsis>
12 <title>Arguments</title>
17 <para>wigner spectrum (lines correspond to the time variable)</para>
23 <para>analyzed signal</para>
29 <para>data window</para>
35 <para>analysis time increment (in samples)</para>
42 length of FFT's. <literal>%pi/zp</literal> gives the frequency increment.
49 <title>Description</title>
51 function which computes the 'time-frequency' wigner
58 a=[488^2 488 1;408^2 408 1;568^2 568 1];
62 p=x'*[t.*t;t;ones(t)];
63 u=[0*ones(408:487) ones(488:568)];
64 s=p.*sin(2*%pi/16*t+u*%pi);
65 s=[0*ones(0:407) s 0*ones(569:951)];
69 plot3d(1:69,1:64,abs(w(1:69,1:64)));
74 <title>Examples</title>
75 <programlisting role="example"><![CDATA[
76 a=[488^2 488 1;408^2 408 1;568^2 568 1];
80 p=x'*[t.*t;t;ones(t)];
82 u=[0*ones(408:487) ones(488:568)];
83 // finite duration sinusoid
84 s=p.*sin(2*%pi/16*t+u*%pi);
85 // signal to be analyzed
86 s=[0*ones(0:407) s 0*ones(569:951)];
87 // 64-point rectangular window
92 plot3d(1:69,1:64,abs(w(1:69,1:64)));