Electronics and Communication Engineering - Networks Analysis and Synthesis - Discussion
Discussion Forum : Networks Analysis and Synthesis - Section 1 (Q.No. 7)
7.
The driving-point impedance Z(s) of a network has a pole-zero locations as shown in the figure. If Z(0) = 3, then Z (s) is
Answer: Option
Explanation:
From figure, The impedance function
and Z(0) = 
while in question Z(0) = 3
= 3 k = 2.
Discussion:
6 comments Page 1 of 1.
Jee said:
9 years ago
Thank you, @Elizebeth.
Yash said:
9 years ago
Z(s) = Z(0) = 3 that's why s = 0.
Snehal mohite said:
9 years ago
Why take s = 0?
Elizebeth said:
10 years ago
From the fig, location of zero is at -3 and the location of poles can be represented as -1+j1 and -1-j1.
Z(s) = k(s+3)/(s+1+j1)(s+1-j1).
= k(s+3)/(s+1)^2+1^2.
= k(s+3)/(s^2+2s+2).
Z(0) = 3 (given).
Substitute s = 0 in Z (s), then:
Z(0) = k(3)/2. Thus k = 2.
Z(s) = 2(s+3)/(s^2+2s+2).
Z(s) = k(s+3)/(s+1+j1)(s+1-j1).
= k(s+3)/(s+1)^2+1^2.
= k(s+3)/(s^2+2s+2).
Z(0) = 3 (given).
Substitute s = 0 in Z (s), then:
Z(0) = k(3)/2. Thus k = 2.
Z(s) = 2(s+3)/(s^2+2s+2).
(2)
Waqar said:
10 years ago
Why it is 3k/2?
Arman said:
1 decade ago
Please explain it clearly.
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