Signals and Systems 1

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

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

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

a) 10

b) 100

c) 50

d) 20

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°

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

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

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)

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

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

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%

Q10. d(t) is a

a) Energy signal

b) Power signal

c) Neither energy nor power

d) None

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

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

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

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

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

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]

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

a) An impulse

b) A parabola

c) A ramp

d) A doublet

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

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

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

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