Code: D-07 Subject: NETWORK AND TRANSMISSION LINES
Time: 3 Hours June 2006 Max. Marks: 100
NOTE: There are 9 Questions in all.
· Question 1 is compulsory and carries 20 marks. Answer to Q. 1. must be written in the space provided for it in the answer book supplied and nowhere else.
· Out of the remaining EIGHT Questions answer any FIVE Questions. Each question carries 16 marks.
· Any required data not explicitly given, may be suitably assumed and stated.
Q.1 Choose the correct or best alternative in the following: (2x10)
a. A line becomes distortionless if
(A) It is properly matched (B) It is terminated into Zo
(C) LG = CR (D) LR = GC
b. Double stub matching eliminates standing waves on the
(A) Source side of the left stub (B) Load side of the right stub
(C) Both sides of the stub (D) In between the two stubs
c. If 
and 
, the
characteristic impedance is
(A)
400
(B)
60
(C) 80 (D)
170
d. The final value
of f (t) for a given 
(A)
Zero (B)
(C) 
(D)
e. If the given network is reciprocal, then according to the reciprocity theorem
(A)
(B)
(C) 
(D)
f. The frequency of
infinite attenuation 
of a low pass m-derived section is
(A)
Equal
to cut off frequency
of the filter.
(B)
.
(C)
Close
to but greater than the 
of the filter.
(D)
Close to
but less than the of the filter.
g. The dynamic impedance of a parallel RLC circuit at resonance is
(A)
(B)
(C) 
(D)
h. Laplace transform
of the function 
is
(A)
(B)
(C) 
(D)
2s.
i. A (3 + 4j) voltage source delivers a current of (4 + j5) A. The power delivered by the source is
(A) 12 W (B) 15 W
(C) 20 W (D) 32 W
j. In a variable
bridged T-attenuator, with 
zero dB attenuation can be obtained
if bridge arm 
and
shunt arm 
are
set as
(A) 
(B) 
(C) 
(D) 
Answer any FIVE Questions out of EIGHT Questions.
Each question carries 16 marks.
Q.2 a. Using
current to voltage transformation, find the current flowing through the resistor
as shown
in Fig.1. (4)
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b. A
current of 
A
flows in a capacitor of value C = 0.22
. Calculate the voltage, charge, and
energy stored in the capacitor at time t =2 sec. (4)
c. Find
the sinusoidal steady state solution 
for a parallel RL circuit. (8)
Q.3 a. Find the Laplace transform of the functions:
(i) 
. (ii)
. (4)
b. Find the convolution
of 
and 
when 
and 
. (4)
c. A unit impulse is applied as input to a series RL circuit with
R = 
and
L = 2H. Calculate the current i(t) through the circuit at time t = 0. (8)
Q.4 a. Define the image impedances of an asymmetric network. Determine the image impedances of the L section shown in Fig.2. (6)
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b. Write short notes on:-
(i) Smith chart and its applications.
(ii) Poles and zeros of a network function. (10)
Q.5 a. State Norton’s
theorem and using Norton’s theorem find the current flowing through the 
resistor. (2+6)
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b. Find
the current in resistor 
of the network using Millman’s
theorem. (8)
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Q.6 a. Find the z parameters of the given network. From the z parameters, find the h parameters equivalent and the ABCD parameters equivalent.
(10)
b. Find the transform impedance Z(s) of the one port network. (6)
|
Q.7 a. Calculate the half power frequencies of a series resonant circuit whose resonant frequency is 150KHz and the band width is 75 KHz. Derive the relations used. (10)
b. The combined inductance of two coils connected in series is 0.6 H and 0.1 H depending on the relative directions of the currents in the coils. If one of the coils, when isolated, has a self inductance of 0.2 H, calculate the mutual inductance and the coefficient of coupling. (6)
Q.8 a. A
loss less line of characteristic impedance 500 is terminated in a pure resistance of
400.
Find the value of standing wave ratio. (4)
b. Why is loading of lines required? Explain the different methods of loading a line. (6)
c. A loss less transmission
line has an inductance of 1.5 mH/Km and a capacitance of 0.02 
. Calculate the
characteristic impedance and phase constant of a transmission line. Assume 
(6)
Q.9 a. Design
a symmetrical bridge T attenuator with an attenuation of 40 dB and an impedance
of 600 . (8)
b. State and prove the
theorem connecting the attenuation constant, 
and characteristic impedance 
of a filter. (4)
c. With the help of frequency response curves, give the classification of filters. (4)