# Signals and Systems 5

Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject: Signals and Systems 5

Part 5: List for questions and answers of Signals and Systems

Q1. FIR digital filter having __________ stability than FIR filter

a) Good stability

b) Poor stability

c) Stability not guaranteed

d) Poor stability

Q2. Which of the following is/are not a property/properties power spectral density function S x(ω)?

a) Sx(ω) is real function of ω

b) Sx(ω)  is a even function of ω

c) Sx(ω) ) is non-positive function of ωS x(ω) ≤ 0 for all ω

d) All of the above

Q3. Fourier series is applicable for

a) Periodic

b) Finite duration

c) Non periodic

d) a and b

Q4. A system with input x[n] and output y[n] is given as y[n] = (sin 5/6 πn) x(n) The system is

a) Linear, stable and invertible

b) Non-linear, stable and non-invertible

c) Linear stable, non invertible

d) Linear, unstable, invertible

Q5. unit step is a

a) Energy signal

b) Power signal

c) Neither energy nor power signal

d) None

Q6. Following is a reason of distortion in communication system

a) External interference

b) Random variations

c) Insufficient Channel Bandwidth

d) All

Q7. The state equations are in the form

a) X = AX + BW

b) X = AX + Bu

c) X = AX + Bx

d) Either (a) or (b)

Q8. The impulse response h[n] of a linear time invariant system is given by h[n] = δ [n + 3 ] + δ [n – 2] -2δ [n -7]. The above system is

a) Stable but non-casual

b) Stable and casual

c) Casual but unstable

d) Unstable and not casual

Q9. The term ‘energy spectral density’ is associated with

a) Periodic waveform

b) Non-periodic waveform

c) Both perodic and non -perodic waveform

d) None of the above

Q10. Highest value of Autocorrelation of a function 100 cos 50 wt is

a) 50

b) 100

c) Zero

d) 150

Q11. Energy density function is always

a) Even

b) Odd

c) Neither even nor odd

d) Both (a) and (b)

Q12. For Ergodic Process

a) Ensemble Average equal to time Average

b) Ensemble Average is not equal to time Average

c) Ensemble Average is greater than Time Average

d) Ensemble Average is less than Time Average

Q13. A system is stable if ROC

a) Include the unit circle

b) Exclude the unit circle

c) Lies on Circle

d) Entire plane

Q14. For formation of state equations, resistance of the circuit

a) Should be in tree

b) Should be in cotree

c) May be in tree or cotree

d) None of the above

Q15. In a Communication system, noise is most likely to affect the signal

a) At the transmitter

b) In the channel

c) In Information source

d) At the destination

Q16. A system is said to be static system, when present output depend upon

a) Present I/P

b) Presrent and past

c) Present and future

d) Past and future

Q17. A stationary process has

a) All statistical properties independent of time

b) All statistical properties dependent of time

c) Zero variance

d) Ensemble average equal to time average

Q18. In a complex wave, the negative half of the wave is a reproduction of the positive half wave. Then

a) The wave contains only fundamental and third harmonic

b) The wave does not contain even harmonics

c) The wave does not contain odd harmonics

d) The wave does not contain triple harmonics

Q19. Out of the three transforms viz. Z-transform, Laplace transform and Fourier transform

a) All three are used in continuous time domain

b) All three are used in both continuous time domain and discrete time domain

c) Z transform is used in continuous time domain while Laplace and Fourier transforms are used in discrete time domain

d) Z transform is used is discrete time domain while Laplace and Fourier transforms are used in continuous time domain

Q20. The signumm function written as [sgn(t)] is defined as

a) sgn(t) = – 1 for t is less than 0, = 0 for t = 0 and = 1 for t is greater than 0

b) sgn(t) = 1 for t is less than 0, = 0 for t = 0 and = – 1 for t is greater than 0

c) sgn(t) = 0 for t is less than 0, = 1 for t = 0 and = 0 for t > 0

d) sgn(t) = 0 for t is less than 0, = 1 for t3 0

Part 5: List for questions and answers of Signals and Systems