548 Practical MATLAB® Applications for Engineers
Error = [part(b)-part(c) versus n
6
8
× 10 −^16
4
2
0
− 2
− 4
− 6
− 5 051015 20 25 30 35
time index n
Amplitude
FIGURE 5.62
Time-domain error given by error = part b − part c of Example 5.14.
Example 5.15
Create the script fi le analys that analyzes the discrete system transfer function given by
He Ge
Fe
ee
ee
jW jW
jW
jW jW
() jW j W
()
()
.
..
509
107 03
2
2
and returns the following:
a. The pole/zero plot of H(ejW) (evaluates the system stability) (Figure 5.63)
b. The plot of abs{H(ejW)} versus W (Figure 5.64)
c. The plot of angle {H(ejW)} versus W
d. List all the poles, zeros, and stand alone term of the transfer function H(z=ejW) and
compare the results obtained with the results of part a
e. Determine the ROC of H(z = ejW)
f. The magnitude of the system poles (length from origin)
g. The partial fraction expansion of H(z)
h. h(n) by using the symbolic MATLAB inverse ZT of H(z)
MATLAB Solution
%Script file = analys
num = [5 0.9 1];
den = [1 -0.7 0.3];
figure(1)
zplane(num,den); title(‘Pole and zero plot of H(z)’)
figure(2)
W = -pi:pi/99:pi;
[H,W] = freqz(num,den,W);