ALAGAPPA CHETTIAR COLLEGE OF ENGINEERING &
TECHNOLOGY, KARAIKUDI- 630 003
Department of Electronics and Communication Engineering
Third Semester
Internal Assessment –3
19ECG31 – SIGNALS AND SYSTEMS
Duration: 90min
Date: 11-12-2020
Maximum Marks : 50
Answer ALL the Questions
Part – A (92=18 Marks)
CO4:
CO4:
CO4:
CO4:
CO4:
CO5:
CO5:
CO5:
CO5:
1. State Sampling theorem.
2. What is Z-Transform and the associated ROC of the signal
x(n)=u(n-n0)?
3.
Consider the analog signal xa(t)=5cos50πt+2sin100πt-2cos100πt.
Determine the minimum Sampling frequency of the signal.
4. How the aliasing process eliminated?
5. Perform circular convolution of the two sequence x1(n)={2,1,2,1}
and x2(n)={1,2,3,4}.
6. Define discrete time Fourier transforms.
7. State the time shifting property of Z-transform.
8.
Define BIBO stability.
9. Determine the transfer function of the system described by the
given state model.
q(n+1)= -2q(n)+0.5x(n); y(n)=0.7q(n).
Part – B (2×16 = 32 Marks)
CO4:
10.
i.
ii.
CO4:
CO5:
11.
12.
Explain how a band limited signal can be sampled without
aliasing?
Find DTFT of the signal x(n)=(0.2)nu(n)+(0.2)-nu(-n-1).
(8)
(8)
i.
(Or)
Find the Z-transform of the signal x(n)=(2/3)nu(n)+(-1/2)nu(n)
and find ROC.
(8)
ii.
Using residue methods find the inverse Z-transform of
i.
H(z)=(1+3z-1)/(1+3z-1+2z-2) , Z>2
(8)
Construct block diagram of the discrete time system
whose input- output relation is described by the difference (8)
equation
y(n)=3.2x(n-2)+0.7x(n)+5y(n-1)+0.35y(n-2)
ii.
Find the state variable matrices A,B,C,D for the equation
CO5:
13.
i.
ii.
y(n)-3y(n-1)-2y(n-2)=x(n)+5x(n-1)+6x(n-2)
(Or)
Explain about state vector, state space and output space of
a discrete time system.
(8)
(6)
A causal system is represented by the difference equation
y(n)+1/4y(n-1)=x(n)+1/2x(n-1). Find the system transfer H(z),
the impulse response and frequency response of the system.
Prepared By
M.Aruna Rani, AP / ECE
HOD / ECE