Electronics And Telecomm (Semester 4)
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.
Q1 Answer the following
a)
Determine if the following system is memoryless, casual, linear, time invariant
y(t) = t x(t)
(5 marks)
00
b)
Explain in brief ROC(Region of Convergence) conditions of Laplace tranform.
(5 marks)
00
c)
Explain Gibbs phenomenon. what is a Gibbs oscillation?
(5 marks)
00
e)
Determine if the given sequence is periodic or not. If periodic, find out fundamental period
x[n] = sin($\frac{6\pi}{7}n +1$)
(5 marks)
00
Q2
a)
Find the response of the time invarient system with impluse response h[n] = {1,2,3,1} using convolution as well as using transform. Verify your answers.
(10 marks)
00
b)
Determine inverse Laplace Transform of
X(s) = $\frac{3x^2 + 8x + 23}{(x+3)(x^2 +2S +10)}$
(10 marks)
00
Q3
a)
Detremine the Fourier transform of the trapezoidal function shown in the figure below:
(10 marks)
00
b)
Find the inverse Z tranform of the following function
(10 marks)
00
X(z) = $\frac{1}{1 - 0.8z^{-1} + 0.12z^{-2}}$
for the following ROCs
a) |z| > 0.6
b) |z| < 0.2
c) 0.2 < |z| < 0.6
Q4
a)
Find out DTFT of the following
(10 marks)
00
- x[n] = {1,-1,-2,2}
- x[n] = $-a^s$ u[-n-1], where |a|<1
b)
An LTI system is described by the following equation. Determine the transfer function and impluse response of the system. Sketch the poles and zeros of the z-plane.
(10 marks)
00
y[n] - 4y[n-1] = x[n-1]
Q5
a)
Find compact trigonometric fourier series for the signal x(t) shown in the following figure, Sktech the amplitude and phase spectra for x(t).
(10 marks)
00
b)
The impluse response of a CT sytem is given below. Determine the unit step response of the system using convolution theorem of Laplace Transform.
(10 marks)
00
b(t) = u(t+2) + u(t-2)
Q6
a)
A Ct signal has been shwon below. Sketch the following signals.
(10 marks)
00
i) x(t-4)
ii) x(4-t)
iii) x(-2t+2)
iv) x(0.5t)
b)
State and proove with appropriate mathematical derivation, convolution in the time domain property and 'time reversal' property of Z transform. Also comment on importance of these properties in the field of communication and signal processing.
(10 marks)
00