EECE 359 MATLAB Exercise 2 1 Introduction 2 Discrete-time ...

EECE359: Matlab Exercise 2 2
2.2 Convolution of an impulse and a square wave
In this section, we will examine the result of a convolution y[n] = δ[n − 1]∗xs[n], were
xs[n] =
Enter the following code to create this signals
>> x = [0 1 0 0 0 0];
>> xs = [1 1 1 1 1 1];
1, 0 ≤ n ≤ 5
0, otherwise
Now, convolve the signals and create a time vector:
>> y = conv(x,xs);
>> t = 0:length(y)-1;
Try plotting the output of the system using stem. What can you observe about the output?
Try shifting the time square wave and/or the impulse. How does this change the
convolution output?
2.3 Convolution of two square waves
In this section, we will try convolving two square waves together. We use again the
function xs[n] defined in Equation 1, and look at the convolution y[n] = xs[n]∗xs[n].
Create xs as we did above. Now, we can perform the convolution:
>> y = conv(xs,xs);
>> t = 0:length(y)-1;
Plot the output using thestem function as we did before. What can you observe about the
convolution of two square waves?
3 Animated Discrete-Time Convolution
In this section, you will learn to create Matlab script files (called M-files), and you will write
a Matlab script which shows an animation of the convolution process. The signals we are
convolving are from page 36 of the Lecture Notes.
3.1 Creating an M-file
Create a new M-file (“File” → “New” → “M-File”), and enter the following code into it (the
line numbers at the left margin are only for reference, and should not be entered in the
file):
(1)