Introduction to MATLAB
Using the file r0.wav afrom the Sonic Visualiser Tutorial.
%% Wav file basics
% File to load
file = ‘r0.wav’;
% Load the audio files
[x fs] = wavread(file);
% Size of variables
size(x)
fs
% Compute length of file in seconds
length_s = size(x,1) / fs
% Convert stereo to mono
x = mean(x, 2);
size(x)
%% Basics
% Ranges
a = 1:4
b = 5:2:11
c = 11:-2:5
% Basic mathematical operations
a + b
a – b
a .* b
a ./ b
% Index into vector
x(1)
x(1:5)
x(5:10)
% Transpose
x(5:10)’
%% Plotting
% Plot time-domain signal
plot(x)
% Plot time-domain signal with correct x-axis
t = (1:size(x,1)) / fs;
plot(t, x)
% Normalize signal to have maximum excursion of 1
excursion = max(abs(x))
x = x / excursion;
max(abs(x))
plot(t, x)
% Label axes
xlabel(‘Time (s)’)
ylabel(‘Amplitude’)
% Title
title(‘R0 Wavform’)
% Zoom with tool
disp(‘Zoom with tool’)
% Zoom in with xlim
origXl = xlim();
xlim([0 1])
% Zoom back out
xlim(origXl)
% Zoom in with ylim
origYl = ylim();
ylim([-0.1 0.1])
% Zoom back out
ylim(origYl)
% Zoom in with axis
origAxis = axis();
axis([0 1 -.1 .1])
% Zoom back out
axis(origAxis)