Solution 10.8.9.1
The MATLAB program
w=logspace(-2,3,200);;
s=j*w;;
K=100
z1 = 1
p1 = 0
p2 = 4
p3 = 4
p4 = 20
%mag = K*abs(s + z1);;
%mag = mag./(abs(s + p1).*abs(s + p2).*abs(s+p3).*abs(s + p4) );;
%mag = 20*log10(mag);;
mag = 20*log10( abs((K.*(s+z1))./( (s+p1).*(s+p2).*(s+p3).*(s+p4))));;
phase = (angle(s+z)-angle(s+p1)-angle(s+p2)-angle(s+p3)-angle(s+p4))*180/pi;;
plot(phase,mag);;
grid on
axis([-270,0,-80 40])
print -deps 10891logmag.eps
draws the log magnitude plot in Figure 1
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-260 -240 -220 -200 -180 -160 -140 -120 -100 -80 -60
-80
-60
-40
-20
0
20
40
Phase in Degrees
Magnitude in decibels
Figure 1: Log magnitude chart for K = 100
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