Solution 9.10.5.3
The MATLAB program
w=logspace(-2,3,200);;
s=j*w;;
z1 = 1
p1 = 0
p2 = 100
phase1 = (angle(s + z1)- angle(s + p1) -angle(s + p2) )*180/pi;;
semilogx(w,phase1)
grid on
axis([0.01,1000,-100,0])
print -deps 91053phase1.eps
%
%
z1 = 10
p1 = 1
p2 = 100
p3 = 500
phase2 = (angle(s + z1)- angle(s + p1) -angle(s + p2)-angle(s + p3) )*180/pi;;
semilogx(w,phase2)
grid on
axis([0.01,1000,-150,0])
print -deps 91053phase2.eps
generates the phase responses shown in Figure 1 and 2 respectively. By
comparing the phase data to that in Figures 9.12 and 9.13, weseethat the
phase data agrees very well.
1
10
-2
10
-1
10
0
10
1
10
2
10
3
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
Frequency in rad/s
Phase in degrees
Figure 1: Phase response Example 9.4.1
2
10
-2
10
-1
10
0
10
1
10
2
10
3
-150
-100
-50
0
Frequency in rad/s
Phase in degrees
Figure 2: Phase response Example 9.4.1
3