Mercurial > hg > ltpda

comparison m-toolbox/html_help/help/ug/interp.html @ 0:f0afece42f48

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Import.
author Daniele Nicolodi <nicolodi@science.unitn.it>
date Wed, 23 Nov 2011 19:22:13 +0100
parents
children
comparison
equal deleted inserted replaced
-1:000000000000 0:f0afece42f48
1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
2 "http://www.w3.org/TR/1999/REC-html401-19991224/loose.dtd">
3
4 <html lang="en">
5 <head>
6 <meta name="generator" content=
7 "HTML Tidy for Mac OS X (vers 1st December 2004), see www.w3.org">
8 <meta http-equiv="Content-Type" content=
9 "text/html; charset=us-ascii">
10
11 <title>Interpolating data (LTPDA Toolbox)</title>
12 <link rel="stylesheet" href="docstyle.css" type="text/css">
13 <meta name="generator" content="DocBook XSL Stylesheets V1.52.2">
14 <meta name="description" content=
15 "Presents an overview of the features, system requirements, and starting the toolbox.">
16 </head>
17
18 <body>
19 <a name="top_of_page" id="top_of_page"></a>
20
21 <p style="font-size:1px;">&nbsp;</p>
22
23 <table class="nav" summary="Navigation aid" border="0" width=
24 "100%" cellpadding="0" cellspacing="0">
25 <tr>
26 <td valign="baseline"><b>LTPDA Toolbox</b></td><td><a href="../helptoc.html">contents</a></td>
27
28 <td valign="baseline" align="right"><a href=
29 "resample.html"><img src="b_prev.gif" border="0" align=
30 "bottom" alt="Resampling data"></a>&nbsp;&nbsp;&nbsp;<a href=
31 "spikeclean.html"><img src="b_next.gif" border="0" align=
32 "bottom" alt="Spikes reduction in data"></a></td>
33 </tr>
34 </table>
35
36 <h1 class="title"><a name="f3-12899" id="f3-12899"></a>Interpolating data</h1>
37 <hr>
38
39 <p>
40 <h2>Description</h2>
41 <p>
42 Interpolation of data can be done in the LTPDA Toolbox by means of
43 <a href="matlab:doc('ao/interp')"><tt>interp</tt></a>.
44 This function interpolates the values in the input AO(s) at new values specified by the
45 input parameter list.
46 </p>
47 <p>
48 <a href="matlab:doc('ao/interp')"><tt>Interp</tt></a> overloads <tt>interp1</tt> function of
49 Matlab Signal Processing Toolbox for AOs.
50 </p>
51 <br>
52 <br>
53 <h2>Syntax</h2>
54 </p>
55 <div class="fragment"><pre>
56 <br>
57 b = interpolate(a, pl)
58 </pre>
59 </div>
60 <h2>Parameters</h2>
61 <p>
62 The following parameters can be set in the method:
63 <ul>
64 <li> <tt>vertices</tt> - specify the new vertices to interpolate on </li>
65 <li> <tt>method</tt> - four methods are available for interpolating data</li>
66 <ul>
67 <li> 'nearest'- nearest neighbor interpolation </li>
68 <li> 'linear' - linear interpolation </li>
69 <li> 'spline' - spline interpolation (default option) </li>
70 <li> 'cubic' - shape-preserving piecewise cubic interpolation </li>
71 </ul>
72 </ul>
73 For details see <tt>interp1</tt> help of Matlab.
74 </p>
75 <p>
76 <h2>Examples</h2>
77 </p>
78 <p>
79 1. Interpolation of a sequence of random data at original sampling rate of 1 Hz
80 by a factor of 10 with no initial phase.
81 </p>
82 <div class="fragment"><pre>
83 <br>
84 <span class="comment">% Signal generation</span>
85 pl = plist(<span class="string">'tsfcn'</span>,<span class="string">'sin(2*pi*1.733*t)'</span>,...
86 <span class="string">'fs'</span>,1,<span class="string">'nsecs'</span>,10,...
87 <span class="string">'yunits'</span>,<span class="string">'V'</span>);
88 x = ao(pl);
89 <span class="comment">% Interpolate on a new time vector</span>
90 t = linspace(0, x.data.nsecs - 1/x.data.fs, 2*len(x));
91 pl_spline = plist(<span class="string">'vertices'</span>,t);
92 pl_nearest = plist(<span class="string">'vertices'</span>,t,<span class="string">'method'</span>,<span class="string">'nearest'</span>);
93 x_spline = interp(x,pl_spline);
94 x_nearest = interp(x,pl_nearest);
95 iplot([x x_spline x_nearest], plist(<span class="string">'Markers'</span>, {<span class="string">'x'</span>, <span class="string">'o'</span>, <span class="string">'+'</span>}, ...
96 <span class="string">'LineColors'</span>, {<span class="string">'k'</span>, <span class="string">'r'</span>}));
97 </pre>
98 </div>
99 <br>
100 <br>
101 <img src="images/interp.png" alt="Interpolate" border="0">
102
103 </p>
104
105 <br>
106 <br>
107 <table class="nav" summary="Navigation aid" border="0" width=
108 "100%" cellpadding="0" cellspacing="0">
109 <tr valign="top">
110 <td align="left" width="20"><a href="resample.html"><img src=
111 "b_prev.gif" border="0" align="bottom" alt=
112 "Resampling data"></a>&nbsp;</td>
113
114 <td align="left">Resampling data</td>
115
116 <td>&nbsp;</td>
117
118 <td align="right">Spikes reduction in data</td>
119
120 <td align="right" width="20"><a href=
121 "spikeclean.html"><img src="b_next.gif" border="0" align=
122 "bottom" alt="Spikes reduction in data"></a></td>
123 </tr>
124 </table><br>
125
126 <p class="copy">&copy;LTP Team</p>
127 </body>
128 </html>