Test answers for Digital Signal Processing Test 2015

69 NOT Answered Yet Test Questions:

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1. Thermal noise can be considered to be ___________.

Answers:

• white non-Gaussian noise

• white Gaussian noise

• flicker noise

• transit time noise

2. For the signal x ( t ) = 3cos50πt + 10sin300πt – cos100πt , nyquist rate is________.

Answers:

• 150 Hz

• 300 Hz

• 100 Hz

• 50 Hz

3. If a Z-Transform is evaluated on the unit circle at evenly spaced points only, it becomes __________.

Answers:

• FFT

• DTFT

• FT

• DFT

4. In DFT, a circularly folded sequence is denoted by_________.

Answers:

• x (( n ))

• x (( n/2 ))

• x (( 2n ))

• x (( -n ))

5. A non-periodic signal has a period ( T ) of _______.

Answers:

• T = ∞

• T = 0

• T = 1

• T = 2

6. The Discrete Fourier Transform ( DFT ) of unit impulse function is__________.

Answers:

• Zero

• Infinity

• 1

• 2

7. How many clock cycles are required by the DSP processor to execute an instruction?

Answers:

• One

• Two

• Four

• Eight

8. In order to design digital filter, an important condition is that, the response of filter should ___________.

Answers:

• causal

• non-causal

• time-variant

• time-invariant

9. Sampling rate conversion by the rational number ( I / D = 1023 / 511 ) needs a polyphase filter with _________.

Answers:

• 511 subfilters

• 500 subfilters

• 1000 subfilters

• 1023 subfilters

10. Environmental parameters like temperature, humidity etc. change the performance of __________.

Answers:

• analog filters only

• digital Filters only

• Both analog and digital filters

• Neither analog nor digital filters

11. The multiplication of two DFTs is equivalent to the circular convolution of their sequences in  the _____________.

Answers:

• frequency domain

• time domain

• Both frequency and time domains

• Neither frequency nor time domain

12. A continuous time signal is said to be symmetrical or even if it satisfies the condition, _________.

Answers:

• x ( t ) = x ( t/2 )

• x ( t ) = x (√t )

• x ( t ) = x ( 2t )

• x ( t ) = x ( -t )

13. Which one of the following is not a register associated with the Program Sequencer?

Answers:

• Arithmetic Status Register (ASTAT)

• Stack Status Register (SSTAT)

• Mode Status Register (MSTAT)

• System Register

14. Digital F.I.R. filters are so designed that they have linear phase characteristics in the  _____________.

Answers:

• stop band

• pass band

• low pass band

• high pass band

15. Continuous time signals have_____________.

Answers:

• periodic spectra

• discrete spectra

• aperiodic spectra

• continuous spectra

16. The condition of periodicity for a discrete time signal can be defined mathematically as ________. (Note: Here Number 'N' is the period of the signal.)

Answers:

• x ( n ) = x ( n + N/2 )

• x ( n ) = x ( n + 2N )

• x ( n ) = x ( n + N )

• None of the above

17. MAC is used for ___________.

Answers:

• high speed addition

• high speed multiplication

• high speed division

• high speed subtraction

18. Quantization of a signal_____________.

Answers:

• reduces bandwidth requirement

• increases bandwidth requirement

• does not have any effect on bandwidth

19. The fundamental period of signal 10sin(12πt) + 4sin(18πt) is______.

Answers:

• 2/3 Sec

• 1/2 Sec

• 1/3 Sec

• 1/4 Sec

20. Which one of the following is a static system?

Answers:

• y ( n ) = x ( n2 )

• y ( n ) = x ( n ) - 3 x (n - 2)

• y ( n ) = x ( - n )

• y ( n ) = n x ( n )

21. Signals that are statistically stationary can be better estimated with  _________.

Answers:

• Short data record

• Long data record

• Average data record

22. In order to avoid aliasing during the reduction of the sampling rate, we divide the sampling frequency by ___________.

Answers:

• D

• 2D

• 4D

• 8D

23. Interfacing of digital systems with different sampling rates can be done efficiently by __________.

Answers:

• reduction of the sampling rate

• interpolation of the sampling rate

• both reduction and interpolation of the sampling rate

• keeping the sampling rate constant

24. In DFT equation, the symbol for circularly even sequence is  _________.

Answers:

• x (( n ))

• x (( n - k ))

• x (( -n ))

• x ( N-n ) = x ( n )

25. Which of the following is a non-causal system?

Answers:

• y ( n ) = x ( n ) + x ( n - 2 )

• y ( n ) = e x (n)

• y ( n ) = cos x ( n )

• y ( n ) = x ( n ) + n x ( n - 1 )

26. The type-1 chebyshev filter contains __________.

Answers:

• all zeros

• all poles

• zeros as well as poles

• No poles and zeros

27. A continuous time signal is also known as a/an_______.

Answers:

• analog signal

• digital signal

• even signal

• odd signal

28. The ADSP-2100A has  ____________.

Answers:

• no on-chip memory

• on-chip memory

• attached memory

• both on-chip and attached memories

29. The periodogram is _________.

Answers:

• not a consistent estimate of the true power density spectrum

• a consistent estimate of the true power density spectrum

• not a consistent estimate of the true energy density spectrum

• a consistent estimate of the true energy density spectrum

30. What is the function of  a Fourier Transform?

Answers:

• It converts the time domain signal into the frequency domain signal

• It converts the frequency domain signal into the time domain signal

• It converts the time domain signal into the phase domain signal

• It converts the frequency domain signal into the phase domain signal

31. The Harvard Architecture referred to the computer architectures that used _____________.

Answers:

• the same data storage for instructions and data

• separate data storages for instructions and data

• no storage for instructions and data

• storage for instructions only

32. The finite impulse response ( F.I.R ) filters are also called_________.

Answers:

• recursive filters

• feedback filters

• non-recursive filters

• notch filters

33. The process of reducing the sampling rate by a factor D is called ___________.

Answers:

• Decimation

• Interpolation

• Dissemination

• Reduction

34. The parametric methods for Power Spectrum Estimation provide __________.

Answers:

• better phase resolution

• better amplitude resolution

• better frequency resolution

• better leakage effects

35. How many stages of FFT algorithm are there for an 8-Point  DFT?

Answers:

• Three

• Two

• One

• Four

36. The MUSIC ( Multiple Signal Classification ) method is used for ____________.

Answers:

• estimation of power spectrum

• estimation of spectral leakage effects

• estimation of amplitude distortion

• estimation of noise frequency

37. The frequency warping effect occurs because of___________.

Answers:

• linear mapping

• frequency expansion

• amplitude attenuation

• non-linear mapping

38. Digital Transmultiplexers are devices for converting ___________.

Answers:

• analog to digital signals

• digital to analog signal

• TDM to FDM

• FDM to CDMA

39. Any arbitrary signal can be expressed as the sum of two signals. These two signals must be_________.

Answers:

• even and odd signals

• periodic and non-periodic signals

• energy and power signals

• deterministic and random signals

40. Linear predictive coding is normally used to achieve __________.

Answers:

• light synthesis

• noise synthesis

• phase synthesis

• speech synthesis

41. The ADSP-21XX family supports  __________.

Answers:

• a 32-bit instruction word

• an 8-bit instruction word

• a 16-bit instruction word

• a 24-bit instruction word

42. Comb Filters can be viewed as ___________.

Answers:

• notch filters

• digital resonators

• all pass filters

• mirror filters

43. Power signals are the signals having ________.

Answers:

• infinite non zero power

• infinite zero power

• finite non zero power

• finite zero power

44. An analog filter is stable if the poles lie  ________________.

Answers:

• on the R.H.S. of the S-Plane

• on the L.H.S. of the S-Plane

• inside the unit circle in the Z-domain

• outside the unit circle in the Z-domain

45. DFT is obtained from DTFT by putting____________.

Answers:

• W = 2πK / N

• W = K / N

• W = πK / 2N

• W = 4πK / N

46. In a Butterworth approximation for bilinear transformation, we have,

Answers:

• Ω= 2 / Ts tan ωc/ 4

• Ω= 1 / Ts tan ωc / 2

• Ω= 2 / Ts tan ωc / 2

• Ω = 1 / Ts tan ωc / 3

47. For the signal x ( t ) = 3cos600πt + 2cos1800πt , the folding frequency is __________.

Answers:

• 600 Hz

• 1800 Hz

• 900 Hz

• 500 Hz

48. The circular frequency shift property is also known as __________.

Answers:

• the quadrature modulation theorem

• the frequency modulation theorem

• the shift modulation theorem

• the circular modulation theorem

49. The non-parametric methods for power spectrum estimation suffer from________.

Answers:

• phase distortion

• spectrum leakage effects

• amplitude distortion

• None of the above

50. The Flanging effect is a ____________.

Answers:

• light effect

• vibration effect

• sound effect

• microwave signal effect

51. Which of the following systems is unstable?

Answers:

• y ( n ) = cos [ x ( n ) ]

• y ( n ) = x ( - n )

• y ( n ) = x ( 2 n )

• None of the above

52. The term "filter" is used to describe a  ___________.

Answers:

• linear time variant system

• causal system

• non-causal system

• linear time invariant system

53. In Multirate Digital Signal Processing, the sampling rate of signals  __________.

Answers:

• is increased

• is decreased

• is either increased or decreased

• remains constant

54. The signal cos(0.01πn) is_________.

Answers:

• non-periodic

• periodic

• an analog signal

• None of the above

55. The ALU of the ADSP 21XX family has two input ports named __________.

Answers:

• A and B

• D and E

• X and Y

• H and L

56. The sampling theorem holds true for the following condition________. (Note:  Here 'fs' is the sampling frequency, and 'w' is the maximum frequency of the continuous time signal x (t)).

Answers:

• fs < 2 ω

• fs > 2 ω

• fs < ω / 2

• fs > ω / 2

57. Which one of the following is not a universal register of the ADSP21XX  family?

Answers:

• Data Address generator (DAG)

• Program Sequencer

• System Register

• Multiplier Results (MR)

58. A discrete time signal can be best analyzed by____________.

Answers:

• a fourier transform

• a laplace transform

• a Z- Transform

• none of the above

59. Which of the following is a time invariant system?

Answers:

• y ( n ) = x ( n ) + n x ( n - 1 )

• y ( n ) = y ( n - 4 ) + x (n - 4)

• y ( n ) = x ( 2 n )

• y ( n ) = x (- n )

60. The Z-Transform is used to analyze ____________.

Answers:

• continuous time signals

• discrete time signals

• random signals

• noise signals

61. The condition of periodicity for a continuous time signal can be defined mathematically as _______. (Note: Here 'To' is the fundamental period.)

Answers:

• x ( t ) = x ( t + 2To )

• x ( t ) = x ( t + To/2 )

• x ( t ) = x ( t + 4To )

• x ( t ) = x ( t + To )

62. A stationary random process is a_________.

Answers:

• finite energy signal

• zero energy signal

• infinite energy signal

63. The ARMA Linear Model is a __________.

Answers:

• non-parametric method

• parametric method

• periodogram method

• eigen-decomposition method

64. In a Butterworth low pass filter, we get a maximally flat response of  ___________.

Answers:

• Pass Band

• Stop Band

• Transition Band

• High Pass Band

65. The overlap save method is for the ___________.

Answers:

• modulation of signals

• filtering of signals

• attenuation of Signals

• amplification of signals

66. Anti-aliasing filter is basically a________.

Answers:

• high pass filter

• low pass filter

• band pass filter

• band stop filter

67. Which of the following is a linear system?

Answers:

• y ( n ) = n x ( n )

• y ( n ) = e x (n)

• y ( n ) = a x ( n ) +6

• y ( n ) = cos x ( n )

68. The Kaiser window design is used for ____________.

Answers:

• butterworth filters

• Chebyshev filters

• Elliptic filters

• F.I.R. filters

69. The aliasing problem can be better handled by the__________.

Answers:

• Quardature Mirror Filter (QMF)

• Brickwall Filter

• Notch Filter

• Digital Resonator