Digital Signal Processing MCQs

Digital Signal Processing MCQs

1: The periodogram is _________.

A.   not a consistent estimate of the true power density spectrum

B.   a consistent estimate of the true power density spectrum

C.   not a consistent estimate of the true energy density spectrum

D.   a consistent estimate of the true energy density spectrum

2: Thermal noise can be considered to be ___________.

A.   white non-Gaussian noise

B.   white Gaussian noise

C.   flicker noise

D.   transit time noise

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

A.   150 Hz

B.   300 Hz

C.   100 Hz

D.   50 Hz

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

A.   FFT


C.   FT

D.   DFT

5: In DFT, a circularly folded sequence is denoted by_________.

A.   x (( n ))

B.   x (( n/2 ))

C.   x (( 2n ))

D.   x (( -n ))

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

A.   T = ∞

B.   T = 0

C.   T = 1

D.   T = 2

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

A.   Zero

B.   Infinity

C.   1

D.   2

8: How many clock cycles are required by the DSP processor to execute an instruction?

A.   One

B.   Two

C.   Four

D.   Eight

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

A.   causal

B.   non-causal

C.   time-variant

D.   time-invariant

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

A.   511 subfilters

B.   500 subfilters

C.   1000 subfilters

D.   1023 subfilters

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

A.   analog filters only

B.   digital Filters only

C.   Both analog and digital filters

D.   Neither analog nor digital filters

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

A.   frequency domain

B.   time domain

C.   Both frequency and time domains

D.   Neither frequency nor time domain

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

A.   x ( t ) = x ( t/2 )

B.   x ( t ) = x (√t )

C.   x ( t ) = x ( 2t )

D.   x ( t ) = x ( -t )

14: Which one of the following is not a register associated with the Program Sequencer?

A.   Arithmetic Status Register (ASTAT)

B.   Stack Status Register (SSTAT)

C.   Mode Status Register (MSTAT)

D.   System Register

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

A.   stop band

B.   pass band

C.   low pass band

D.   high pass band

16: Continuous time signals have_____________.

A.   periodic spectra

B.   discrete spectra

C.   aperiodic spectra

D.   continuous spectra

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

A.   x ( n ) = x ( n + N/2 )

B.   x ( n ) = x ( n + 2N )

C.   x ( n ) = x ( n + N )

D.   None of the above

18: MAC is used for ___________.

A.   high speed addition

B.   high speed multiplication

C.   high speed division

D.   high speed subtraction

19: Quantization of a signal_____________.

A.   reduces bandwidth requirement

B.   increases bandwidth requirement

C.   does not have any effect on bandwidth

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

A.   2/3 Sec

B.   1/2 Sec

C.   1/3 Sec

D.   1/4 Sec

21: Which one of the following is a static system?

A.   y ( n ) = x ( n2 )

B.   y ( n ) = x ( n ) - 3 x (n - 2)

C.   y ( n ) = x ( - n )

D.   y ( n ) = n x ( n )

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

A.   Short data record

B.   Long data record

C.   Average data record

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

A.   D

B.   2D

C.   4D

D.   8D

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

A.   reduction of the sampling rate

B.   interpolation of the sampling rate

C.   both reduction and interpolation of the sampling rate

D.   keeping the sampling rate constant

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

A.   x (( n ))

B.   x (( n - k ))

C.   x (( -n ))

D.   x ( N-n ) = x ( n )

26: Which of the following is a non-causal system?

A.   y ( n ) = x ( n ) + x ( n - 2 )

B.   y ( n ) = e x (n)

C.   y ( n ) = cos x ( n )

D.   y ( n ) = x ( n ) + n x ( n - 1 )

27: The type-1 chebyshev filter contains __________.

A.   all zeros

B.   all poles

C.   zeros as well as poles

D.   No poles and zeros

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

A.   analog signal

B.   digital signal

C.   even signal

D.   odd signal

29: The ADSP-2100A has ____________.

A.   no on-chip memory

B.   on-chip memory

C.   attached memory

D.   both on-chip and attached memories

30: What is the function of a Fourier Transform?

A.   It converts the time domain signal into the frequency domain signal

B.   It converts the frequency domain signal into the time domain signal

C.   It converts the time domain signal into the phase domain signal

D.   It converts the frequency domain signal into the phase domain signal

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

A.   the same data storage for instructions and data

B.   separate data storages for instructions and data

C.   no storage for instructions and data

D.   storage for instructions only

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

A.   recursive filters

B.   feedback filters

C.   non-recursive filters

D.   notch filters

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

A.   Decimation

B.   Interpolation

C.   Dissemination

D.   Reduction

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

A.   better phase resolution

B.   better amplitude resolution

C.   better frequency resolution

D.   better leakage effects

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

A.   Three

B.   Two

C.   One

D.   Four

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

A.   estimation of power spectrum

B.   estimation of spectral leakage effects

C.   estimation of amplitude distortion

D.   estimation of noise frequency

37: The frequency warping effect occurs because of___________.

A.   linear mapping

B.   frequency expansion

C.   amplitude attenuation

D.   non-linear mapping

38: Digital Transmultiplexers are devices for converting ___________.

A.   analog to digital signals

B.   digital to analog signal

C.   TDM to FDM

D.   FDM to CDMA

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

A.   even and odd signals

B.   periodic and non-periodic signals

C.   energy and power signals

D.   deterministic and random signals

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

A.   light synthesis

B.   noise synthesis

C.   phase synthesis

D.   speech synthesis

41: The ADSP-21XX family supports __________.

A.   a 32-bit instruction word

B.   an 8-bit instruction word

C.   a 16-bit instruction word

D.   a 24-bit instruction word

42: Comb Filters can be viewed as ___________.

A.   notch filters

B.   digital resonators

C.   all pass filters

D.   mirror filters

43: Power signals are the signals having ________.

A.   infinite non zero power

B.   infinite zero power

C.   finite non zero power

D.   finite zero power

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

A.   on the R.H.S. of the S-Plane

B.   on the L.H.S. of the S-Plane

C.   inside the unit circle in the Z-domain

D.   outside the unit circle in the Z-domain

45: DFT is obtained from DTFT by putting____________.

A.   W = 2πK / N

B.   W = K / N

C.   W = πK / 2N

D.   W = 4πK / N

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

A.   Ω= 2 / Ts tan ωc/ 4

B.   Ω= 1 / Ts tan ωc / 2

C.   Ω= 2 / Ts tan ωc / 2

D.   Ω = 1 / Ts tan ωc / 3

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

A.   600 Hz

B.   1800 Hz

C.   900 Hz

D.   500 Hz

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

A.   the quadrature modulation theorem

B.   the frequency modulation theorem

C.   the shift modulation theorem

D.   the circular modulation theorem

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

A.   phase distortion

B.   spectrum leakage effects

C.   amplitude distortion

D.   None of the above

50: The Flanging effect is a ____________.

A.   light effect

B.   vibration effect

C.   sound effect

D.   microwave signal effect