Andhra University 2007 B.E SIGNALS AND SYSTEMS - exam paper

II Year B.E./B.Tech Degree exam


SIGNALS AND SYSTEMS
Electronics & Communication Engineering

Time : 3 hours Maximum : 75 Marks

ques. one is compulsory

ans any 4 from ques. two to 8

All ques. carry equal marks

1. a. What is meant by signal? Contrast the differences ranging from energy and power signal. [3]

b) discuss operations on signals [3]

c) How can we represent a signal by orthogonal set of functions in time? [3]

d) discuss various kinds of signals [3]

e) How many various kinds of signal transformations are there and discuss with example. [3]

2. a) describe Z-transform and its properties. [8]

b) obtain the Z-Transform of x(n)=-anu(-n-1). And provide
the region of convergence. [7]

3. a) describe Fourier transform and its properties [10]

b) obtain the Fourier tranform of x(n)=e-at cos (wt+F) .[ 5]

4. a) State and Prove Sampling Theorem. [8]

b) What is the effect of aliasing discuss with example. [7]

5. a) How do you represent a discrete time signal as sum of infinite impulses? [8]

b) describe inverse Z-transform and methods of deducing it. [7]

6. a) discuss auto-correlation and cross-correlation of signals by taking necessary examples [6]

b) discuss Basic operation that can be performed on the signals [9]

7. a) discuss discrete Time Decimation and Interpolation[ 5]

b) describe trigonometric Fourier Series and provide the formulae for the Fourier coefficients. [10]

8. Write a note on [15]

a) Causality
b) Stability
c) Linearity

Earning:   Approval pending.