PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

34 Practical MATLAB® Applications for Engineers

R.1.108 For example, create the script fi le triangles that returns the plots over two cycles of
the triangular sequences, with period T = 2 π, with the following specs:
a. f 1 (t) versus t, with positive slope during 50% of the period T, and a swing from
− 1 to + 1
b. f 2 (t) versus t, with positive slope during 25% of the period T, and a swing from
− 2 to + 2
c. f 3 (t) versus t, with a positive slope during 33% of the period T, and a swing from
− 3 to + 3
d. f 4 (t) versus t, with a positive slope during 75% of the period T, and a swing from
− 4 to + 4

MATLAB Solution

% Script file: triangles

t = 0:0.1*pi:4*pi;

f1 = sawtooth(t,.5);

f2 = 2*sawtooth(t,.25);

f3 = 3*sawtooth(t,.33);

f4 = 4*sawtooth(t,.75);

subplot(2,2,1)

plot(t,f1)

ylabel (‘f1(t)’)

axis ([0 4*pi -1.5 1.5])

grid on;

title (‘Sawtooth(t,.50) vs t’)

subplot(2,2,2)

plot(t,f2)

ylabel( ‘f2(t)’)

axis ([0 4*pi -2.5 2.5])

grid on;

title (‘2*Sawtooth(t,.25) vs t’)

subplot (2,2,3)

plot (t,f3)

axis ([0 4*pi -4.5 4.5])

grid on;

ylabel(‘ f3(t) ‘);xlabel(‘ t (time)’)

title(‘3*Sawtooth(t,.33) vs t’)

subplot(2,2,4)

plot(t,f4)

axis([0 4*pi -5.5 5.5])

grid on;

title(‘4*Sawtooth(t,.75) vs t’)

ylabel(‘ f4(t) ‘); xlabel(‘ t (time) ’)

The script fi le triangles is executed and the results are shown in Figure 1.31.

R.1.109 The MATLAB function sinc(x) evaluates the function defi ned by

sin ( )

sin( )

cx

x

x





R.1.110 For example, the script fi le sincs returns the plot of the function sinc(x) over the
range 5 ≤ x ≤ 5 , illustrated in Figure 1.32.