B B4812 Pages: 3
Reg No.: Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
FOURTH SEMESTER B.TECH DEGREE EXAMINATION, APRIL 2018
Course Code: EC202
Course Name: SIGNALS & SYSTEMS
Max. Marks: 100 Duration: 3 Hours
PART A
Answer any two questions, each carries 15 marks Marks
1 2) Determine whether the signal x[m] = 1+sin (= + =) is periodic. Find the (2)
fundamental period if it is periodic.
b) एण the signal f(t) shown below: (7)
i) Sketch 13-20
ii) Find the energy of the signal 110).
AL -1 0 | t
c) Check whether the following systems are linear and stable. (6)
6) >(£) = ‏3ا‎
‎(11) 1 [7] = x[n— 1]
2 ஐ Let f(t) = 2(u(t) —u(t - 2)) and g(t) = 6 (u(t) - ८(६- 2))
(i) Sketch the functions f(t) and g(t) (2)
(11) Compute /(t)*g(t). Here * denotes convolution. (7)
b) Define the cross correlation function ഗു (7) for two signals x(t) and y(t). What (2)
is its connection with convolution?
c) Consider an LTI system with impulse response A[m] = ulm]. Determine the (4)
stability and causality of this system.
3 a) 120 the convolution of a signal [7] = (1, —1,1, —1} with itself. (6)
1
b) Check whether the system described by the input output relationship y[n] = ഗ്മ] (3)
is time invariant.
c) Determine the power and energy of the following signals. Classify them as (6)

energy/power signals.
(1) x(t) = Asin(Ot)
(ii) x[n] = un]

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