Electronics And Telecomm (Semester 3)
Total marks: 80
Total time: 3 Hours
INSTRUCTIONS
(1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Draw neat diagrams wherever necessary.
1.a.
Draw equivalent circuit for given magnetically coupled circuit.
(5 marks)
00
1.b.
In the given network of Fig., switch is opened at t = 0. Solve for v and $\frac{d v}{d t}$ at t = 0+.
(5 marks)
00
1.c.
Prove that AD − BC = 1 for Transmission parameters.
(5 marks)
00
1.d.
Define the following parameter of transmission lines:
i. Input impedance
ii. Characteristics Impedance
iii. VSWR
iv. Reflection Coefficient
v. Transmission Coefficient
(5 marks)
00
2.a.
In the network shown in Fig., switch is changed from position 1 to position 2 at t = 0, steady condition having reached before switching. Find the values of i, $\frac{d i}{d t} \quad$ and $\frac{d 2 i}{d t 2}$ at t = 0+.
(10 marks)
00
2.b.
For the network shown in Fig., find Z and Y-parameters.
(10 marks)
00
3.a.
Find currents in the three meshes of network shown in Fig.
(10 marks)
00
3.b.
The parameters of a transmission lines arc are R = 65Ω/km, L=1.6mH/km, G = 2.25 mmho/km, C=0.1μF/km. Find
i. Characteristic Impedance
ii. Propagation Constant
iii. Attenuation Constant
iv. Phase Constant at 1kHz
(10 marks)
00
4.a.
Determine whether following functions are positive real
i) $\frac{s^{4}+3 s^{3}+s^{2}+s+2}{s^{3}+s^{2}+s+1}$
ii) $\frac{s(s+3)(s+5)}{(s+1)(s+4)}$
(10 marks)
00
4.b.
Obtain Thevenin equivalent network of Fig.,
(10 marks)
00
5.a.
Find Y-parameters for the network shown in Fig.,
(10 marks)
00
5.b.
Realize the following functions in Foster II and Cauer I form $Z(s)=\frac{2\left(s^{2}+1\right)\left(s^{2}+9\right)}{s\left(s^{2}+4\right)}$
(10 marks)
00
6.a.
A transmission line has a characteristics impedance of 50 ohm and terminate in a load $Z_{L}=25+$ j50 ohm. Use smith chart and Find VSWR and Reflection coefficient at the load.
(10 marks)
00
6.b.
In the network of Fig., switch is in position 'a' for a long time. At t = 0 switch is moved from a to b. Find v₂ (t). Assume that the initial current in 2 H inductor is zero.
(10 marks)
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