M.Sc. (Semester II) (CBCS) Examination, 2017
ELECTRONICS
SIGNALS AND SYSTEMS
Day Date: Friday, 28-04-2017 Max. Marks: 70
Time: 10.30 AM to 01.00 PM
N.B. Q no. 1 Q. no. 2 are compulsory.
Attempt any three questions from Q. no. 3 to 7
Attempt five questions.
Q.1 Choose the correct Answer: 08
The periodic signals satisfying the conditions then it
is said to have half wave symmetry.


is
An energy signal
Neither an energy signal nor a power signal
A power signal
An energy as well as a power signal
If is odd, then its fourier series coefficients must be
Real and even Real and odd
Imaginary and odd Imaginary and even
To obtain From the given signal the following
precedence rule is used for operations on the independent
variable
Time scaling Time shifting Refection
Reflection Time scaling Time shifting
Time scaling Reflection Time shifting
Time shifting Time scaling Reflection
In the fourier series coefficients of a signal are periodic then
the signal must be
continuous time, periodic discrete time, periodic
continuous time, non-periodic discrete time, non-periodic
The fourier series coefficient of the shifted signal are

e-jnwtcn ejnwtcn ewtcn e-wtcn
Which of the following is purely even signal?
X(t)=Acosw0t X(t)=ejwot
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In MATLAB sign is for the assignment operator.

State true or false: 06
On multiplying a non-casual signal by unit step function then
it became casual.
For energy signal the power is Zero.
The amplitude of anti-symmetric signal is always one at
origin.
The system that require memory are called static system.
Mathematically unit step function is derivative of unit impulse
function.
A LTI system is casual if impulse response is equal to zero.
Q.2 Attempt any two: 10
Define a system. How the systems are classified?
Write a note on different types of file used in Matlab.
Check whether the following system are time variant or not
ii) a
Write a Matlab program to plot a continuous time cosine signal
and its sampled version.
04
Q.3 Obtain the fourier components of the periodic square wave
which is symmetrical with respect to the
Figure 1
vertical axis at time as shown in figure 1
08
With regard to fourier series representation, justify the following
statement
Odd functions have only sine terms.
Even functions have no sine terms.
Functions with half-wave symmetry have only odd
harmonics.
06
Q.4 Obtain liner convolution of following sequence using graphical
method and
08
Prove that LTI system is completely characterized by unit
impulse function.
06
Q.5 A discrete signal is defined as
for n
1 for 0 n 3
0 elsewhere
08

T/2 T/4 T/4 T/2
1
0
1
t
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Determine its value and sketch the signal
Sketch the signal that result if we
1st fold then the delay the resulting sequence by 4
samples.
ii) 1st delay by 4 sample then fold the resulting signal.
Express the sequence in terms of sequence and

Determine impulse response of the DT-LTI system in terms of
unit impulse input for
06
Q.6 State and prove parsevals theorem for complex exponential
fourier series.
08



Determine whether the following system is liner or not 06
Q.7 Obtain the trigonometric fourier series for the half-wave rectified
sine wave shown in figure 2.
Figure 2
08
Sketch the continuous time signal x(t)=2sin t for n interval
sample the continuous time signal with sampling
period T=0.2 sec and sketch the s=discrete time signal.