32 Practical MATLAB® Applications for Engineers
R.1.105 The MATLAB command square(t, a) returns the periodic square wave with period
T = (^2) π, over the range defi ned by t, where a is a constant that indicates the per-
cent of the period T for which the square wave is positive.
R.1.106 For example, create the script fi le squares that returns the plots over two cycles of
the square sequences, with period T = 2 π, with the following specs:
a. f 1 (t) versus t, with mag[f 1 (t)] = 1 , during 50% of the period T and mag[f 1 (t)] = − 1 ,
during the remaining 50%
b. f 2 (t) versus t, with mag[f 2 (t)] = 2 , during 25% of the period T and mag[f 2 (t)] = − 2 ,
during the remaining 75%
c. f 3 (t) versus t, with mag[f 3 (t)] = 3 , during 33% of the period T and mag[f 3 (t)] = − 3 ,
during the remaining 67%
d. f 4 (t) versus t, with mag[f 4 (t)] = 4 , during 75% of the period T and mag[f 4 (t)] = − 4 ,
during the remaining 25%
MATLAB Solution
% Script file: squares
t = 0:.1pi:4pi;
f1 =square(t,50);
f2 =2square(t,25);
f3 =3square(t,33);
f4 =4square(t,75);
subplot(2,2,1)
plot(t,f1)
ylabel(‘f1(t)’)
axis([0 4pi -1.5 1.5])
grid on;
title(‘Square(t,50) vs t’)
subplot(2,2,2)
plot(t,f2)
heaviside (t)t versus t
3
2.5
2
1.5
1
0.5
0
− 1 −0.5 0 0.5 1 1.5 2 2.5 3
t
t*u(t)
FIGURE 1.29
Plot of t u(t) of R.1.104.