PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

DTFT, DFT, ZT, and FFT 487

MATLAB Solution

%script file: sym _ z _ plots

syms a b n

f1 _ n = 1^n;

F1 _ z = ztrans(f1 _ n)

f2 _ n = a^n;

F2 _ z = ztrans(f2 _ n)

f3 _ n = 1^n*cos(a*n);

F3 _ z = ztrans(f3 _ n)

f4 _ n = 1^n*sin(a*n);

F4 _ z = ztrans(f4 _ n)

figure(1)

subplot(2,2,1)

ezplot(F1 _ z)

subplot(2,2,2);

F2 _ z=subs(F2 _ z,a,0.5);

ezplot(F2 _ z);

subplot(2,2,3);

F3 _ z=subs(F3 _ z,a,0.5);

ezplot(F3 _ z);

subplot(2,2,4);

F4 _ z = subs(F4 _ z,a,0.5);

ezplot(F4 _ z);

>> sym _ z _ plot

The script file sym _ z _ plots and the results are shown in

Figure 5.15.

See Figure 5.15.

− 505

0

0.5

1

0.5

1.5

1

0

2

1

0

−0.5

0.5

1

1.5

− 4 − 202

z z

− 505

z

− 505

z

46

(z-cos(1/2)) z/(z^2 -2 z cos(1/2)+1) z sin(1/2)/(z^2 -2 z cos(1/2)+1)

z/(z-1) 2 z/(2 z-1)

FIGURE 5.15

Plots of the ZTs of R.5.78.