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Problem 8.07PP
The following transfer function is a lag network designed to introduce a gain attenuation of
10(-20 db) at w = 3 rad/sec:
H{s) =
l O s + l
1 0 0 s + 1
(a) Assume a sampling period of T= 0.25 sec, and compute and plot in the z-plane the poie and
zero iocations of the digital implementations o1 H(s) obtained using (1) Justin’s method and (2)
pole-zero mapping. For each case, compute the amount of gain attenuation provided by the
network at z1 = eyojl T .
(b) For each of the equivalent digital systems in part (a), plot the Bode magnitude curves over the
frequency range w = 0.01 to 10 rad/sec.
(b) For each of the equivalent digital systems in part (a), plot the Bode magnitude curves over the
frequency range w = 0.01 to 10 rad/sec.
Step-by-step solution
step 1 of 2
w Let
H {sy-
lOff+l
lOOs+1
|/ /p ® ) | = ® = 3= 0 .1001 (-2 i^ )
Tustin's method
/ / ( z ) = 0.10112.-
-0.97531
+ 0.99750
Step 2 of 2
(b) All there are es sentially the same and indistinguishable on the plot because the
range o f intere st is below the half s an^le frequency