Fourier Series and LTI Systems MCQ’s

Electronics & Communication Engineering Signals & Systems

This set of Signals & Systems Multiple Choice Questions & Answers (MCQs) focuses on “Fourier Series and LTI Systems”.

1. Which of the following is a causal system?
a) y(n) = 3x(n) – 2x(n-1)
b) y(n) = 3x(n) + 2x(n+1)
c) y(n) = 3x(n+1) + 2x(n-1)
d) y(n) = 3x(n+1) + 2x(n-1) + x(n)

2. Which of the following is a dynamic system?
a) y(n) = y(n-1) + y(n+1)
b) y(n) = y(n-1)
c) y(n) = x(n)
d) y(n) + y(n+1) + y(n+3) = 0

3. Which system among the following is a time invariant system?
a) y(n) = n x(n)
b) y(n) = x(n) – x(n-1)
c) y(n) = x(-n)
d) y(n) = x(n) cos 2nf

4. A series RC circuit excited by voltage V is __________
a) A memory less system
b) A causal system
c) A dynamic system
d) Static system

5. Given a stable and causal system with impulse response h (t) and system function H(s). Let us suppose H(s) is rational, contains a pole at s=-2 and does not have a zero at origin and location of all other zeroes is unknown, poles are present at some unknown location other than the origin. Then,
i) H(s) = H(-s)
ii) dh(t)dt Contains at least one pole in its Laplace transform.
Which of the following options is correct?
a) i – true, ii – true
b) i – false, ii – true
c) i – true, ii – false
d) i – false, ii – false

6. If y(t) = ex(t), then the relation is _________
a) Dynamic
b) Static
c) Memory
d) Memoryless but not static

7. A LTI system is characterized by ___________
a) Unit impulse response
b) Time shifted impulses
c) Unit step response
d) Response to any signal(bounded)

8. From the given conditions, what are the Dirichlet conditions?
i. X(t) should be absolutely integrable
ii. X(t) should have finite discontinuities
iii. X(t) should have a finite number of maxima as well as minima in its domain
a) i, ii and iii
b) i and ii
c) i and iii
d) ii and iii

9. A signal e-at sin (ωt) is the input to a real linear time-invariant system. Given K and ∅ are constants, the output of the system will be of the form Ke-bt sin (vt + ∅). The correct statement among the following is __________
a) b need not be equal to a but v must be equal to ω
b) v need not be equal to ω but b must be equal to a
c) b must be equal to a and v must be equal to ω
d) b need not be equal to a and v need not be equal to ω

10. A system is said to be dynamic if the output of the system depends on ___________
a) The past Input
b) The Future Input
c) The Present Input
d) Both the Present and future Inputs

11. The element which can weaken a signal system is ___________
a) Attenuation
b) Distortion
c) Noise
d) Attenuation, Distortion & Noise

12. Which of the following is true about the bounded signal?
a) A finite signal is always bounded
b) A bounded signal always possess finite energy
c) A bounded signal is always zero outside a given interval
d) A bounded signal is always finite

13. The system x(k)=7(13)ku(−k−1)–6(12)ku(k) is ___________
a) Causal
b) Anti-causal
c) Non-causal
d) Cannot be determined

14. The difference between the highest and lowest frequencies of a signal is _________
a) Frequency
b) Period
c) Bandwidth
d) Amplitude

15. A system is said to be causal if the output of the system depends on ___________
a) The Past and Present Inputs
b) The Present Inputs
c) The Future Inputs
d) The Past and Future Inputs

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