(Replacing page with 'Lecture 1')
Line 1: Line 1:
−
Here is a Matlab script reflecting Lecture 1.  The script plays various audio signals. Copy and paste the script into an m-file and play:
+
[[Lecture 1]]
−
 
+
−
load handel; %Loads 2 variables, y and Fs.  y is a signal containing
+
−
information: a vector of numbers representing an audio clip.  Fs is the
+
−
sampling frequency.
+
−
 
+
−
sound(y,Fs); %play the audio file at the appropriate sampling frequency.
+
−
 
+
−
input('Press enter to hear the same audio with 1/4 the samples')
+
−
 
+
−
downsample = 4; %factor to decrease sampling rate by
+
−
sound(y(1:downsample:end)*downsample,Fs/downsample); %Plays the same signal with only
+
−
1/4 of the original "information." Note the degradation in quality
+
−
 
+
−
input('Press enter to hear the same audio with 1/100 of the original samples')
+
−
 
+
−
downsample = 100; %factor to decrease sampling rate by
+
−
sound(y(1:downsample:end)*downsample,Fs/downsample); %Plays the same signal with only
+
−
1/100 of the original "information." Original audio is nearly unrecognizable.
+
−
 
+
−
input('Press enter to hear a constant tone note A')
+
−
 
+
−
delta = 0.00005; %Sampling period
+
−
t = 1:delta:3; %a vector representing 3 seconds of time
+
−
x = sin(2*pi*440*t); %a vector representing the sinusoid tone A
+
−
 
+
−
sound(x,1/delta);
+
−
 
+
−
input('Press enter to hear a tone note A an octave higher')
+
−
x = sin(2*pi*880*t); %a vector representing the sinusoid tone A an octave higher
+
−
 
+
−
sound(x,1/delta);
+

Revision as of 06:43, 15 June 2009

Lecture 1

Retrieved from "https://www.projectrhea.org/rhea/index.php?title=Lectures&oldid=31835"
Shortcuts
Help Main Wiki Page Random Page Special Pages Log in
Search

Alumni Liaison

Basic linear algebra uncovers and clarifies very important geometry and algebra.

Dr. Paul Garrett