Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject: Signals and Systems 1

**Part 1: List for questions and answers of Signals and Systems**

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**Q1. Which one most appropriate 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**

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**Q2. An energy signal has G(f) = 10. Its energy density spectrum is**

**a) 10**

**b) 100**

**c) 50**

**d) 20**

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**Q3. In an ac circuit the fundamental component of current wave lags the corresponding ****voltage wave by 20°. The third harmonic component of current wave lags the corresponding ****voltage by an angle**

**a) Less than 20°**

**b) More than 20°**

**c) Equal to 20°**

**d) Equal to or more than 20°**

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**Q4. A voltage V(t) is a Gaussian ergodic random process with a mean of zero and a variance ****of 4 volt^2. If it is measured by a dc meter. The reading will be**

**a) 0**

**b) 4**

**c) 2**

**d) Square root of 2**

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**Q5. If transfer function of a system is H(z) = 6 + z^-1 + z^-2 then system is**

**a) Minimum phase**

**b) Maximum phase**

**c) Mixed phase**

**d) None**

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**Q6. Which one is a linear system?**

**a) y[n] = x[n] x x[n – 1]**

**b) y[n] = x[n] + x[n – 10]**

**c) y[n] = x^2[n]**

**d) (a) and (c) **

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**Q7. The analog signal m(t) is given below m(t) = 4 cos 100 d t + 8 sin 200 d t + cos 300 d t, ****the Nyquist sampling rate will be**

**a) 1/100**

**b) 1/200**

**c) 1/300**

**d) 1/600**

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**Q8. In Laplace transform, multiplication by e^-at in time domain becomes**

**a) Translation by a in s domain**

**b) Translation by (-a) in s domain**

**c) Multiplication by e^-as in s domain**

**d) None of the above**

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**Q9. A voltage wave having 5% fifth harmonic content is applied to a series RC circuit. The ****percentage fifth harmonic content in the current wave will be**

**a) 5%**

**b) More than 5%**

**c) Less than 5%**

**d) Equal or more than 5%**

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**Q10. d(t) is a**

**a) Energy signal**

**b) Power signal**

**c) Neither energy nor power**

**d) None**

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**Q11. The analog signal given below is sampled by 600 samples per second for m(t) = 3 sin ****500 d t + 2 sin 700 d t then folding frequency is**

**a) 500 Hz**

**b) 700 Hz**

**c) 300 Hz**

**d) 1400 Hz**

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**Q12. Two function g1(t) and g2(t) with correlation of 6 has average power of 4 and 5 ****respectively. The power of g1(t) + g2(t) is**

**a) 9**

**b) 21**

**c) 3**

**d) 15 **

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**Q13. A signal g(t) = A then g(t) is a**

**a) Energy signal**

**b) Power signal**

**c) Neither energy nor power signal**

**d) Insufficient data**

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**Q14. The Fourier series of an odd periodic function contains**

**a) Odd harmonics only**

**b) Even harmonics only**

**c) Cosine harmonics only**

**d) Sine harmonics only**

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**Q15. As per time displacement theorem in Laplace transformation, displacement in the time ****domain by T becomes**

**a) Division by s in the s domain**

**b) Division by e^-sT in the s domain**

**c) Multiplication by s in the s domain**

**d) Multiplication by e^-sT in the s domain**

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**Q16. Which one 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]**

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**Q17. Double integration of a unit step function would lead to**

**a) An impulse**

**b) A parabola**

**c) A ramp**

**d) A doublet**

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**Q18. An impulse function consist of**

**a) Pure dc**

**b) Pure a.c**

**c) Entire frequency range with constant phase**

**d) Infinite bandwidth with linear phase vaariations **

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**Q19. If f(t) = A d(t – a), F(s) is**

**a) A e^-as**

**b) A e^as**

**c) A a e^-as**

**d) Aa e^as**

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**Q20. Damped sinusoids are _____**

**a) Sinusoid signals multiplied by growing exponentials**

**b) Sinusoid signals divided by growing exponentials**

**c) Sinusoid signals multiplied by decaying exponentials**

**d) Sinusoid signals divided by decaying exponentials **

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**Part 1: List for questions and answers of Signals and Systems**

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**Q1. Answer: a**

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**Q2. Answer: b**

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**Q3. Answer: b**

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**Q4. Answer: a**

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**Q5. Answer: a**

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**Q6. Answer: b**

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**Q7. Answer: c**

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**Q8. Answer: a**

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**Q9. Answer: b**

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**Q10. Answer: b**

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**Q11. Answer: c**

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**Q12. Answer: b**

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**Q13. Answer: b**

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**Q14. Answer: d**

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**Q15. Answer: d**

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**Q16. Answer: a**

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**Q17. Answer: b**

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**Q18. Answer: c**

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**Q19. Answer: a**

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**Q20. Answer: c**