\[
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\newcommand{\CC}{\mathbb{C}}
\newcommand{\GG}{\mathbb{G}}
\newcommand{\LL}{\mathbb{L}}
\newcommand{\PP}{\mathbb{P}}
\newcommand{\QQ}{\mathbb{Q}}
\newcommand{\RR}{\mathbb{R}}
\newcommand{\VV}{\mathbb{V}}
\newcommand{\ZZ}{\mathbb{Z}}
\newcommand{\FF}{\mathbb{F}}
\newcommand{\KK}{\mathbb{K}}
\newcommand{\UU}{\mathbb{U}}
\newcommand{\EE}{\mathbb{E}}
\newcommand{\Aa}{\mathcal{A}}
\newcommand{\Bb}{\mathcal{B}}
\newcommand{\Cc}{\mathcal{C}}
\newcommand{\Dd}{\mathcal{D}}
\newcommand{\Ee}{\mathcal{E}}
\newcommand{\Ff}{\mathcal{F}}
\newcommand{\Gg}{\mathcal{G}}
\newcommand{\Hh}{\mathcal{H}}
\newcommand{\Ii}{\mathcal{I}}
\newcommand{\Jj}{\mathcal{J}}
\newcommand{\Kk}{\mathcal{K}}
\newcommand{\Ll}{\mathcal{L}}
\newcommand{\Mm}{\mathcal{M}}
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\newcommand{\Pp}{\mathcal{P}}
\newcommand{\Qq}{\mathcal{Q}}
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\newcommand{\Ss}{\mathcal{S}}
\newcommand{\Tt}{\mathcal{T}}
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\newcommand{\Ww}{\mathcal{W}}
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\newcommand{\qqsubjqq}{ \qquad \text{subject to} \qquad }
\]
Introduction to Signal Processing
This numerical tour explores some basic signal processing tasks.
Contents
Installing toolboxes and setting up the path.
You need to download the following files: signal toolbox and general toolbox.
You need to unzip these toolboxes in your working directory, so that you have toolbox_signal and toolbox_general in your directory.
For Scilab user: you must replace the Matlab comment '%' by its Scilab counterpart '//'.
Recommandation: You should create a text file named for instance numericaltour.sce (in Scilab) or numericaltour.m (in Matlab) to write all the Scilab/Matlab command you want to execute. Then, simply run exec('numericaltour.sce'); (in Scilab) or numericaltour; (in Matlab) to run the commands.
Execute this line only if you are using Matlab.
getd = @(p)path(p,path);
Then you can add the toolboxes to the path.
getd('toolbox_signal/');
getd('toolbox_general/');
Loading and Displaying Signals
Signals are 1D vectors, usually stored as (n,1) arrays, where n is the number of samples.
n = 512;
Load a signal. (function load_signal.m should be in the toolbox of each course)
f = load_signal('Piece-Regular', n);
One can force to be a column vector (just to be sure).
f = f(:);
One can rescale to [0,1] the entries of the signal.
f = rescale(f);
Display the signal.
clf;
plot(1:n, f);
axis('tight');
title('My title');
set_label('variable x', 'variable y');
You can display several figures using subplot
subplot(2, 2, 1);
plot(f); axis('tight');
subplot(2, 2, 4);
plot(f.^2); axis('tight');
You can display several signals on the same figure
clf;
plot(1:n, [f f.^2]');
legend('signal', 'signal^2');
Undefined function or variable 'exo1'.
Error in index (line 88)