MU Electronics and Telecom Engineering (Semester 3)
Circuits and Transmission Lines
December 2016
Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary


1(a) In the network shown in fig. (1), find the voltages V1 and V2
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5 M
1(b) For the network shown in fig(2), determine the current i(t) when the switch is closed at t = 0 with zero initial conditions.
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5 M
1(c) Find the equivalent of symmetric π -network shown in figure (3).
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5 M
1(d) Define the following parameters of transmission line
i) Input impedance
ii) Characteristics impedance
iii) VSWR
iv) Reflection coefficient
v) Transmission coefficient
5 M

2(a) In the network shown in fig.(4) the switch closese at t = 0. The capacitor has no initial charge. Find VC(t) and iC(t).
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10 M
2(b) Determine the transmission parameters of the network shown in fig (5) using the concept of inter connection of two port network.
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10 M

3(a) For the network shown in fig (6), calculate the maximum power that may be dissipated in the load resistoo RL.
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10 M
3(b) A load impedance ZL=(30 +j 60)Ω is connected a 50Ω transmission line of 2 cm length and operated at 2 Ghz. Using Smith Chart, find the imput impedance of transmission line under the assumption that phase velocity is 50% of speed of light.
10 M

4(a) An impedance is given by-
\[Z(s)=\frac{8\left ( S^2+1 \right )\left ( s^2+3 \right )}{s\left ( s^2+2 \right )\left ( s^2+4 \right )}\] Realise the network in Foster-I and Cauer-I from
10 M
4(b) In the coupled circuit of figure (7), find the input impedance as well as the net inductance.
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10 M

5(a) Find the open circuit impedance parameters of the circuit shown in fig. (8). Also find the Y parameters.
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10 M
5(b)(i) i) State properties of LC driving point impedance functions.
5 M
5(b)(ii) Test whether the polynomial is Hurwitz
\[p(s)= S^7+2S^6+2S^5+S^4+4S^3+8S^2+8S+4\]
5 M

6(a) A c0-axial line has the following parameters
R=6Ω/m
L=5.2×10-8H/m
G=6×10-3mho/m
C= 2.136×10-10F/m
f = 1GHz
ZL=(100+ j 100) Ω
Compute the following parameter using formulacs
i) Characteritics impedance
ii) Propagation constant
iii) Reflection coefficient at the load
iv) Transmission coefficient at the load
10 M
6(b) In the network shown in fig.(9), the switch is closed at t=0. Find the current i1(t) and i2(t) whe initial current through the inductor is zero and initial voltage is 4 volt.
!mage
10 M



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