PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

66 Practical MATLAB® Applications for Engineers

Example 1.8

Let f(n) be given by

fn

nn

n

nn

()

00 2

10 1

12



   

   

 and











Create the script fi le f_ n that returns the following:

a. Plot of [f(n)] versus n

b. Plot of [f(n)]^2 versus n

c. Plot of [-f(n)] versus n

d. Plot of [f(n − 2)] versus n

e. The energy of [f(n)]

f. The power of [f(n)]

MATLAB Solution

% Script file: f _ n

fn = [zeros(1,100) ones(1,10) [1.1:0.1:2] zeros(1,81)];

n = -10:0.1:10;

subplot(2,2,1);

plot(n, fn);

title(‘f(n) vs n’);ylabel(‘Amplitude’);

axis([-1 5 -.2 2.3]);

subplot(2,2,2);

fnsquare = fn.^2;

plot(n, fnsquare);ylabel(‘Amplitude’);

title(‘[f(n)]^2 vs. n’);

FIGURE 1.56
Plots of f 5 (t), f 6 (t), f 7 (t), and f 8 (t) of Example 1.7.

f5(t) versus t, (Example 1.7)

f7(t) versus t, (Example 1.7) f8(t) versus t, (Example 1.7)

f6(t) versus t, (Example 1.7)

0.2

0.1

0

−0.1

0.2

0.1

−0.1

0

f5(t)

f5(t) f5(t)

1 2 3 4

1

1.5

1

0.5

0

−0.5

− 5 05

f5(t)

2 2.5 3 3.5 4

t

0.5

−0.5

− 1

− 5 05

0

t