Solution to ECE Test #7 S05
Below are some pole-zero plots of transfer functions of systems of the general form,
H (s) = A
( s − z1 ) ( s − zN )
( s − p1 ) ( s − pD )
in which A = 1, the z’s are the zeros and the p’s are the
poles. Answer the following questions. (The use of the term “one(s)” means there might
be more than one answer. In that case provide all the correct answers.) One point per
correct answer.
1.
Which one(s) have a magnitude frequency response that is non-zero at ω = 0 ?
A,D,E,F
2.
Which one(s) have a magnitude frequency response that is non-zero as ω → ∞ ?
A,F
3.
There are two which have a bandpass frequency response (zero at zero and zero at
infinity). Which one is more underdamped (higher Q)? C
4.
Which one has a magnitude frequency response whose shape is closest to being a
bandstop filter? F
5.
Which one(s) have a magnitude frequency response that approaches K / ω 6 at very
high frequencies (K is a constant)? E
6.
Which one has a magnitude frequency response that is constant ? A
7.
Which one has a magnitude frequency response whose shape is closest to an ideal
lowpass filter? D
8.
Which one(s) have a phase frequency response that is discontinuous at ω = 0 ? B,C
A
B
ω
6
[s]
C
ω
6
[s]
4
4
4
2
2
2
σ
0
σ
0
D
ω
6
[s]
2
σ
0
2
2
4
4
4
4
2
0
2
4
6
6
6
4
2
E
[s]
4
2
2
σ
0
2
4
4
2
0
6
6
6
2
4
6
[s]
σ
0
2
4
4
ω
6
4
6
6
2
F
ω
6
0
6
6
4
2
0
2
4
6
4
2
0
2
4
6
σ
0
2
4
[s]
4
2
6
6
ω
6
6
6
4
2
0
2
4
6