Top 200 Digital Signal Processing Objective Questions and Answers

 Top 200 Digital Signal Processing Objective Questions and Answers

1. DTFT is the representation of
a) Periodic Discrete time signals
b) Aperiodic Discrete time signals
c) Aperiodic continuous signals
d) Periodic continuous signals
Answer: Aperiodic Discrete time signals
2. The interface between an analog signal and a digital processor is
a) D/A converter
b) A/D converter
c) Modulator
d) Demodulator
Answer: A/D converter
3. The speech signal is obtained after
a) Analog to digital conversion
b) Digital to analog conversion
c) Modulation
d) Quantization
Answer: Digital to analog conversion
4. x(n)=x(n-1)/4 with initial condition x(0)-1, gives the sequence
a) x(n)= (1/4)^n
b) x(n)= -(1/4)^n
c) x(n)= (1/4)^-n
d) x(n)= (-1/4)^-n
Answer: x(n)= -(1/4)^n
5. For a system function H(s) to be stable
a) The zeros lie in left half of the s plane
b) The zeros lie in right half of the s plane
c) The poles lie in left half of the s plane
d) The poles lie in right half of the s plane
Answer: The poles lie in left half of the s plane
6. Telegraph signals are examples of
a) Digital signals
b) Analog signals
c) Impulse signals
d) Pulse train
Answer: Digital signals
7. Roll-off factor is
a) The bandwidth occupied beyond the Nyquis Bandwidth of the filter
b) The performance of the filter or device
c) Aliasing effect
d) None of the above
Answer: The bandwidth occupied beyond the Nyquist Bandwidth of the filter
8. A discrete time signal may be
1) Samples of a continuous signal
2) A time series which is a domain of integers
3) Time series of sequence of quantities
4) Amplitude modulated wave
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 1 and 3 are correct
d) All the four are correct
Answer: 1, 2 and 3 are correct
9. The process of conversion of continuous time signal into discrete time signal is known as
a) aliasing
b) sampling
c) convolution
d) none of the above
Answer: sampling
10. The discrete impulse function is defined by
a) δ(n) = 1, n ≥ 0 = 0, n ≠ 1
b) δ(n) = 1, n = 0 = 0, n ≠ 1
c) δ(n) = 1, n ≤ 0 = 0, n ≠ 1
d) δ(n) = 1, n ≤ 0 = 0, n ≥ 1
Answer: δ(n) = 1, n = 0 = 0, n ≠ 1
11. The Nyquist theorem for sampling
1) Relates the conditions in time domain and frequency domain
2) Helps in quantization
3) Limits the bandwidth requirement
4) Gives the spectrum of the signal
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 1 and 3 are correct
d) All the four are correct
Answer: 1 and 3 are correct
12. The transforming relations performed by DTFT are
1) Linearity
2) Modulation
3) Shifting
4) Convolution
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 1 and 3 are correct
d) All the four are correct
Answer: All the four are correct
13. Frequency selectivity characteristics of DFT refers to
a) Ability to resolve different frequency components from input signal
b) Ability to translate into frequency domain
c) Ability to convert into discrete signal
d) None of the above
Answer: Ability to resolve different frequency components from input signal
14. FFT may be used to calculate
1) DFT
2) IDFT
3) Direct Z transform
4) In direct Z transform
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 1 and 3 are correct
d) All the four are correct
Answer: 1 and 2 are correct
15. The computational procedure for Decimation in frequency algorithm takes
a) Log2 N stages
b) 2Log2 N stages
c) Log2 N2 stages
d) Log2 N/2 stages
Answer: Log2 N stages
16. The filter that may not be realized by approximation of derivatives techniques are
1) Band pass filters
2) High pass filters
3) Low pass filters
4) Band reject filters
a) 1, 2 and 3 are correct
b) 2 and 4 are correct
c) 2 and 3 are correct
d) All the four are correct
Answer: 2 and 4 are correct
17. The transformations are required for
1) Analysis in time or frequency domain
2) Quantization
3) Easier operations
4) Modulation
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 1 and 3 are correct
d) All the four are correct
Answer: 1 and 3 are correct
18. The similarity between the Fourier transform and the z transform is that
a) Both convert frequency spectrum domain to discrete time domain
b) Both convert discrete time domain to frequency spectrum domain
c) Both convert analog signal to digital signal
d) Both convert digital signal to analog signal
Answer: Both convert discrete time domain to frequency spectrum domain
19. DIT algorithm divides the sequence into
a) Positive and negative values
b) Even and odd samples
c) Upper higher and lower spectrum
d) Small and large samples
Answer: Even and odd samples
20. The ROC of a system is the
a) range of z for which the z transform converges
b) range of frequency for which the z transform exists
c) range of frequency for which the signal gets transmitted
d) range in which the signal is free of noise
Answer: range of z for which the z transform converges
21. As compared to the analog systems, the digital processing of signals allow
1) Programmable operations
2) Flexibility in the system design
3) Cheaper systems
4) More reliability
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 1, 2 and 4 are correct
d) All the four are correct
Answer: All the four are correct
22. The several ways to perform an inverse Z transform are
1) Direct computation
2) Long division
3) Partial fraction expansion with table lookup
4) Direct inversion
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 2 and 3 are correct
d) All the four are correct
Answer: All the four are correct
23. The anti causal sequences have ______ components in the left hand sequences.
a) Positive
b) Negative
c) Both a and b
d) None of the above
Answer: Positive
24. The Cooley–Tukey algorithm of FFT is a
a) Divide and conquer algorithm
b) Divide and rule algorithm
c) Split and rule algorithm
d) Split and combine algorithm
Answer: Divide and conquer algorithm
25. For an expanded power series method, the coefficients represent
a) Inverse sequence values
b) Original sequence values
c) Negative values only
d) Positive values only
Answer: Inverse sequence values
26. The region of convergence of x/ (1+2x+x2) is
a) 0
b) 1
c)  Negative
d) Positive
Answer: 1
27. The IIR filter designing involves
a) Designing of analog filter in analog domain and transforming into digital domain
b) Designing of digital filter in analog domain and transforming into digital domain
c) Designing of analog filter in digital domain and transforming into analog domain
d) Designing of digital filter in digital domain and transforming into analog domain
Answer: Designing of digital filter in analog domain and transforming into digital domain
28. IIR filter design by approximation of derivatives has the limitations
1) Used only for transforming analog high pass filters
2) Used for band pass filters having smaller resonant frequencies
3) Used only for transforming analog low pass filters
4) Used for band pass filters having high resonant frequencies
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 2 and 3 are correct
d) All the four are correct
Answer: 2 and 3 are correct
29. In direct form for realisation of IIR filters,
1) Denominator coefficients are the multipliers in the feed forward paths
2) Multipliers in the feedback paths are the positives of the denominator coefficients
3) Numerator coefficients are the multipliers in the feed forward paths
4) Multipliers in the feedback paths are the negatives of the denominator coefficients
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 3 and 4 are correct
d) All the four are correct
Answer: 3 and 4 are correct
30. The s plane and z plane are related as
a) z = esT
b) z = e2sT
c) z = 2esT
d) z = esT/2
Answer: z = esT
31. The direct form II for realisation involves
1) The realisation of transfer function into two parts
2) Realisation after fraction
3) Product of two transfer functions
4) Addition of two transfer functions
a) 1, 2 and 3 are correct
b) 1 and 3 are correct
c) 3 and 4 are correct
d) All the four are correct
Answer: 1 and 3 are correct
32. The advantage of using the cascade form of realisation is
1) It has same number of poles and zeros as that of individual components
2) The number of poles is the product of poles of individual components
3) The number of zeros is the product of poles of individual components
4) Over all transfer function may be determined
a) 1, 2 and 3 are correct
b) 1 and 3 are correct
c) 1 and 4 are correct
d) All the four are correct
Answer: 1 and 4 are correct
33. In DSP processors, which among the following maintains the track of addresses of input data as well as the coefficients stored in data and program memories?
a) Data Address Generators (DAGs)
b) Program sequences
c) Barrel Shifter
d) MAC
Answer: Data Address Generators (DAGs)
34. Which among the following represent/s the characteristic/s of an ideal filter?
a) Constant gain in passband
b) Zero gain in stop band
c) Linear Phase Response
d) All of the above
Answer: All of the above
35. In tapped delay line filter, the tapped line is also known as ________
a) Pick-on node
b) Pick-off node
c) Pick-up node
d) Pick-down node
Answer: Pick-off node
36. How is the sensitivity of filter coefficient quantization for FIR filters?
a) Low
b) Moderate
c) High
d) Unpredictable
Answer: Low
37. Decimation is a process in which the sampling rate is __________.
a) enhanced
b) stable
c) reduced
d) unpredictable
Answer: reduced
38. Anti-imaging filter with cut-off frequency ωc = π/ I is specifically used _______ upsampling process for the removal of unwanted images.
a) Before
b)  At the time of
c) After
d) All of the above
Answer: After
39. FIR filters ________
A) are non-recursive
B) do not adopt any feedback
C) are recursive
D) use feedback
a) A & B
b) C & D
c) A & D
d) B & C
Answer: A & B
40. Which units are generally involved in Multiply and Accumulate (MAC)?
a) Adder
b) Multiplier
c) Accumulator
d) All of the above
Answer: All of the above
41. If F, is sampling frequency then the relation between analog frequency F and digital frequency f is 
a) f= F/(2F)s
b) f= (F)s/F
c) f= F/(F)s
d) f= 2F/(F)s
Answer: f= F/(F)s
42. The cascade realisation of IIR systems involves
1) The transfer function broken into product of transfer functions
2) The transfer function divided into addition of transfer functions
3) Factoring the numerator and denominator polynomials
4) Derivatives of the transfer functions
a) 1, 2 and 3 are correct
b) 1 and 3 are correct
c) 3 and 4 are correct
d) All the four are correct
Answer: 1 and 3 are correct
43. The DFT is preferred for
1) Its ability to determine the frequency component of the signal
2) Removal of noise
3) Filter design
4) Quantization of signal
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 1 and 3 are correct
d) All the four are correct
Answer: 1 and 3 are correct
44. For the analog and digital IIR filters to be casual, the number of zeros should be
a) >= Number of poles. 
b)  <= Numbers of poles.
c) = Number of poles.
d) Zero.
Answer: Zero.
45. Time reversal of a discrete time signal refers to
a) y[n] = x[-n+k]
b) y[n] = x[-n]
c) y[n] = x[-n-k]
d) y[n] = x[n-k]
Answer: y[n] = x[-n]
46. The norm or length of a signal is given by
a) The square of the energy of the signal
b) The square root of the energy of the signal
c) The inverse of the energy of the signal
d) The cube root of the energy of the signal
Answer: The square root of the energy of the signal
47. Padding of zeros increases the frequency resolution.
a) True
b) False
Answer: False
48. A signal x[n] is anti symmetric or odd when
a) x[-n] = x[n] • x[n]
b) x[n] = -x[n]
c) x[n] = [x[n]]2
d) x[-n] = -x[n]
Answer: x[-n] = -x[n]
49. Time shifting of discrete time signal means
a) y[n] = x[n-k]
b) y[n] = x[-n-k]
c) y[n] = -x[n-k]
d) y[n] = x[n+k]
Answer: y[n] = x[n-k]
50. The cost of the digital processors is cheaper because
a) Processor allows time sharing among a number of signals
b) The hardware is cheaper
c) Require less maintenance
d) Less power consumption
Answer: Processor allows time sharing among a number of signals
51. Causal systems are the systems in which
a) The output of the system depends on the present and the past inputs
b) The output of the system depends only on the present inputs
c) The output of the system depends only on the past inputs
d) The output of the system depends on the present input as well as the previous outputs
Answer: The output of the system depends on the present and the past inputs
52. The basic properties of DFT includes
1) Linearity
2) Periodicity
3) Circular symmetry
4) Summation
a) 1, 2 and 3 are correct
b) 1, 2 and 4 are correct
c) 1 and 3 are correct
d) All the four are correct
Answer: 1, 2 and 3 are correct
53. The operations that may be performed on vectors in Euclidean Space are
1) Inner product, distance between vectors
2) Norm of a vector, orthogonal vectors
3) Orthonormal functions
4) Vector division
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 1, 2 and 4 are correct
d) All the four are correct
Answer: 1, 2 and 3 are correct
54. Circular shift of an N point is equivalent to
a) Circular shift of its periodic extension and its vice versa
b) Linear shift of its periodic extension and its vice versa
c) Circular shift of its aperiodic extension and its vice versa
d) Linear shift of its aperiodic extension and its vice versa
Answer: Linear shift of its periodic extension and its vice versa
55. The circular convolution of two sequences in time domain is equivalent  to
a) Multiplication of DFTs of two sequences
b) Summation of DFTs of two sequences
c) Difference of DFTs of two sequences
d) Square of multiplication of DFTs of two sequences
Answer: Multiplication of DFTs of two sequences
56. For the calculation of N- point DFT, Radix -2 FFT algorithm repeats
a) 2(N Log2 N) stages
b) (N Log2 N)2/2 stages
c) (N Log2 N)/2 stages
d) (N Log2(2 N))/2 stages
Answer: (N Log2 N)/2 stages
57. Radix - 2 FFT algorithm performs the computation of DFT in
a) N/2Log2 N multiplications and 2Log2 N additions
b) N/2Log2 N multiplications and NLog2 N additions
c) Log2 N multiplications and N/2Log2 N additions
d) NLog2 N multiplications and N/2Log2 N additions
Answer: N/2Log2 N multiplications and NLog2 N additions
58. The overlap save method is used to calculate
a) The discrete convolution between a sampled signal and a finite impulse response (FIR) filter
b) The discrete convolution between a sampled signal and an infinite impulse response (IIR) filter
c) The discrete convolution between a very long signal and a finite impulse response (FIR) filter
d) The discrete convolution between a very long signal and a infinite impulse response (IIR) filter
Answer: The discrete convolution between a very long signal and a finite impulse response (FIR) filter
59. Overlap-Add Method Deals with principles that
a) The linear convolution of a discrete-time signal of length L and a discrete-time signal of length M produces a discrete-time convolved result of length L + M - 1
b) The linear convolution of a discrete-time signal of length L and a discrete-time signal of length M produces a discrete-time convolved result of length L + M
c) The linear convolution of a discrete-time signal of length L and a discrete-time signal of length M produces a discrete-time convolved result of length 2L + M - 1
d) The linear convolution of a discrete-time signal of length L and a discrete-time signal of length M produces a discrete-time convolved result of length 2L + 2M - 1
Answer: The linear convolution of a discrete-time signal of length L and a discrete-time signal of length M produces a discrete-time convolved result of length L + M - 1
60. The principle of Gram-Schmidt Orthogonalization (GSO) states that, any set of M energy signals can be expressed as
a) Summation of N ortho normal basis functions, where N ≤ M.
b) Linear combinations of N ortho normal basis functions, where N ≤ M.
c) Product of logarithmic combinations of N ortho normal basis functions, where N ≤ M.
d) Product of inverse squares of N ortho normal basis functions, where N ≤ M.
Answer: Linear combinations of N ortho normal basis functions, where N ≤ M.
61. Damping is the ability of a system
a) To support oscillatory nature of the system’s transient response
b) To oppose the continuous nature of the system's transient response
c) To oppose the oscillatory nature of the system's transient response
d) To support the discrete nature of the system's transient response
Answer: To oppose the oscillatory nature of the system's transient response
62. The condition for a system to be causal is
a) All poles of its transfer function must be left half of s-plane
b) All poles of its transfer function must be right half of s-plane
c) All zeros of its transfer function must be right half of s-plane
d) All zeros of its transfer function must be left half of s-plane
Answer: All poles of its transfer function must be right half of s-plane
63. The condition for a system to be stable is
a) All poles of its transfer function lie on the left half of s-plane
b) All poles of its transfer function must be right half of s-plane
c) All zeros of its transfer function must be right half of s-plane
d) All zeros of its transfer function must be left half of s-plane
Answer: All poles of its transfer function lie on the left half of s-plane
64. Partial fraction method involves
a) Allotting coefficients
b) Dividing the numerator by denominator to get fractions
c) Dividing single fraction into parts
d) None of the above
Answer: Dividing single fraction into parts
65. The factors formed for partial fraction are a combination of
1) Linear factors
2) Irreducible quadratic factors
3) Square roots
4) Cube roots
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 2 and 3 are correct
d) All the four are correct
Answer: 1 and 2 are correct
66. For a partial fraction method to be followed,
1) The degree of the numerator must be more than the degree of the denominator.
2) The factors formed for partial fraction are a combination of Linear factors and Irreducible quadratic factors.
3) The degree of the numerator must be less than the degree of the denominator.
4) The factors formed for partial fraction are a combination of Linear factors and Square roots.
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 2 and 3 are correct
d) All the four are correct
Answer: 2 and 3 are correct
67. ROC does not have
a) zeros
b) poles
c) negative values
d) positive values
Answer: poles
68. The impulse invariant method is obtained by
a) Sampling the impulse response of an equivalent analog filter
b) Taking backward difference for the derivative
c) Mapping from s-domain to z-domain
d) Approximation of derivatives
Answer: Sampling the impulse response of an equivalent analog filter
69. The transformation technique in which there is one to one mapping from s-domain to z-domain is
a) Approximation of derivatives
b) Impulse invariance method
c) Bilinear transformation method
d) Backward difference for the derivative
Answer: Bilinear transformation method
70. The frequency warping is referred as
1) lower frequencies in analog domain expanded in digital domain
2) lower frequencies in digital domain expanded in analog domain
3) non linear mapping
4) compression of higher frequencies
a) 1, 3 and 4 are correct
b) 2 and 4 are correct
c) 2 and 3 are correct
d) All the four are correct
Answer: 1, 3 and 4 are correct
71. The magnitude response of Butterworth filter has
1) Flat stop band
2) Flat pass band
3) Tapering pass band
4) Tapering stop band
a) 1 and 2 are correct
b) 2 and 4 are correct
c) 2 and 3 are correct
d) All the four are correct
Answer: 1 and 2 are correct
72. In the cascaded form of realisation, the polynomials are factored into
a) a product of 1st-order and 2nd-order polynomials
b) a product of 2nd-order and 3rd-order polynomials
c) a sum of 1st-order and 2nd-order polynomials
d) a sum of 2nd-order and 3rd-order polynomials
Answer: a product of 1st-order and 2nd-order polynomials
73. The partial fraction of x2+1/x(x-1)2 is
a) 1/ (x-1) + 2/(x-1)2 - 1/x
b) 1/ (x-1) + 2/(x-1)2 - 3/x
c) 1/ (x-1) + 2/(x-1)2 - 3/x2
d) 1/ (x+1) + 2/(x+1)2 - 1/x
Answer: 1/ (x-1) + 2/(x-1)2 - 1/x
74. A partial-fraction expansion of the transfer function in Z-1 leads to
a) The parallel form II structure
b) The parallel form I structure
c) Cascaded structure
d) None of the above
Answer: The parallel form I structure
75. A direct partial-fraction expansion of the transfer function in Z leads to
a) The parallel form II structure
b) The parallel form I structure
c) Cascaded structure
d) None of the above
Answer: The parallel form II structure
76. Basically, group delay is the delayed response of filter as a function of ________.
a) Phase
b) Amplitude
c) Frequency
d) All of the above
Answer: Frequency
77. A filter is said to be linear phase filter if the phase delay and group delay are _______
a) High
b) Moderate
c) Low
d) Constant
Answer: Constant
78. Which among the following has/have a provision to support an adaptive filtering mechanism?
a) IIR
b) FIR
c) Both a and b
d) None of the above
Answer: Both a and b
79. In DAGs, which register/s provide/s increment or step size for index register especially during the register move?
a) Index Register
b) Length & Base Register
c) Modify Register
d) All of the above
Answer: Modify Register
80. In direct form realization for an interpolator, which among the following generates an intermediate signal?
a) Upsampler
b)  Downsampler
c)  Anti-imaging filter
d) Anti-aliasing filter
Answer: Upsampler
81. To change the sampling rate for better efficiency in two or multiple stages, The decimation and interpolation factors must be _________unity.
a) Less than
b) Equal to
c) Greater than
d) None of the above
Answer: Greater than
82. Which addresses is are generated by Program Sequences?
a) Data Address
b) Instruction Address
c) Both a and b
d) None of the above
Answer: Instruction Address
83. Which is/are the correct way/s for the result quantization of an arithmetic operation?
a) Result Truncation
b) Result Rounding
c) Both a and b
d) None of the above
Answer: Both a and b
84. Which among the below mentioned transform pairs is/are formed between the auto-correlation function and the energy spectral density, in accordance to the property of Energy Spectral Density (ESD)?
a) Laplace Transform
b) Z-Transform
c) Fourier Transform
d) All of the above
Answer: Fourier Transform
85. According to the time-shifting property of Laplace Transform,  shifting the signal in time domain corresponds to the ______
a) Multiplication by e-st0 in the time domain
b) Multiplication by e-st0 in the frequency domain
c) Multiplication by est0 in the time domain
d) Multiplication by est0 in the frequency domain
Answer: Multiplication by e-st0 in the frequency domain
86. What should be location of poles corresponding to ROC for bilateral Inverse Laplace Transform especially for determining the nature of time domain signal?
a) On L.H.S of ROC
b) On R.H.S of ROC
c) On both sides of ROC
d) None of the above
Answer: On both sides of ROC
87. Unilateral Laplace Transform is applicable for the determination of linear constant coefficient differential equations with ________
a) Zero initial condition
b) Non-zero initial condition
c) Zero final condition
d) Non-zero final condition
Answer: Non-zero initial condition
88. What should be the value of laplace transform for the time-domain signal equation e-at cos ωt.u(t)?
a) 1 / s + a with ROC σ > - a
b) ω / (s + a) 2 + ω2 with ROC σ > - a
c) s + a / (s + a)2 + ω2 with ROC σ > - a
d) Aω / s2 + ω2 with ROC σ > 0
Answer: s + a / (s + a)2 + ω2 with ROC σ > - a
89. Generally, the convolution process associated with the Laplace Transform in time domain results into________
a) Simple multiplication in complex frequency domain
b) Simple division in complex frequency domain
c) Simple multiplication in complex time domain
d) Simple division in complex time domain
Answer: Simple multiplication in complex frequency domain
90. An impulse response of the system at initially rest condition is basically a response to its input & hence also regarded as
a) Black's function
b) Red's function
c) Green's function
d) None of the above
Answer: Green's function
91. Which result is generated/ obtained by the addition of a step to a ramp function?
a) Step Function shifted by an amount equal to ramp
b) Ramp Function shifted by an amount equal to step
c) Ramp function of zero slope
d) Step function of zero slope
Answer: Ramp Function shifted by an amount equal to step
92. Correlogram is a graph of ______
a) Amplitude of one signal plotted against the amplitude of another signal
b) Frequency of one signal plotted against the frequency of another signal
c) Amplitude of one signal plotted against the frequency of another signal
d) Frequency of one signal plotted against the time period of another signal
Answer: Amplitude of one signal plotted against the amplitude of another signal
93. Which theorem states that the total average power of a periodic signal is equal to the sum of average powers of the individual fourier coefficients?
a) Parseval's Theorem
b) Rayleigh's Theorem
c) Both a & b
d) None of the above
Answer: Parseval's Theorem
94. According to Rayleigh's theorem, it becomes possible to determine the energy of a signal by________
a) Estimating the area under the square root of its amplitude spectrum
b) Estimating the area under the square of its amplitude spectrum
c) Estimating the area under the one-fourth power of its amplitude spectrum
d) Estimating the area exactly half as that of its amplitude spectrum
Answer: Estimating the area under the square of its amplitude spectrum
95. What does the spectral density function of any signal specify?
a) Distribution of energy or power
b) Consumption of energy or power
c) Conservation of energy or power
d) Generation of energy or power
Answer: Distribution of energy or power
96. Parallel form of realisation is done in
a) High speed filtering applications
b) Low speed filtering applications
c) Both a and b
d) None of the above
Answer: High speed filtering applications
97. The ESD of a real valued energy signal is always  _________
a) An even (symmetric) function of frequency
b) An odd (non-symmetric) function of frequency
c) A function that is odd and half-wave symmetric
d) None of the above
Answer: An even (symmetric) function of frequency
98. Which among the below mentioned assertions is /are correct?
A) Greater the value of correlation function, higher is the similarity level between two signals
B) Greater the value of correlation function, lower is the similarity level between two signals
C) Lesser the value of correlation function, higher is the similarity level between two signals
D) Lesser the value of correlation function, lower is the similarity level between two signals
a) Only C
b) Only B
c) A & D
d) B & C
Answer: A & D
99. Which function has a provision of determining the similarity between the signal and its delayed version?
a) Auto-correlation Function
b) Cross-correlation Function
c) Both a & b
d) None of the above
Answer: Auto-correlation Function
100. Which property is exhibited by the auto-correlation function of a complex valued signal?
a) Commutative property
b) Distributive property
c) Conjugate property
d) Associative property
Answer: Conjugate property
101. Where does the maximum value of auto-correlation function of a power signal occur?
a) At origin
b) At extremities
c) At unity
d) At infinity
Answer: At origin
102. What does the set comprising all possible outcomes of an experiment known as?
a) Null event
b) Sure event
c) Elementary event
d) None of the above
Answer: Sure event
103. What does an each outcome in the sample space regarded as?
a) Sample point
b) Element
c) Both a & b
d) None of the above
Answer: Both a & b
104. Mutually Exclusive events ________
a) Contain all sample points
b) Contain all common sample points
c) Does not contain any common sample point
d) Does not contain any sample point
Answer: Does not contain any common sample point
105. What would be the probability of an event 'G' if G denotes its complement, according to the axioms of probability?
a) P (G) = 1 / P (G)
b) P (G) = 1 - P (G)
c) P (G) = 1 + P (G)
d) P (G) = 1 * P (G)
Answer: P (G) = 1 - P (G)
106. What would happen if the two events are statistically independent?
a) Conditional probability becomes less than the elementary probability
b) Conditional probability becomes more than the elementary probability
c) Conditional probability becomes equal to the elementary probability
d) Conditional as well as elementary probabilities will exhibit no change
Answer: Conditional probability becomes equal to the elementary probability
107. What is the value of an area under the conditional PDF?
a) Greater than '0' but less than '1'
b) Greater than '1'
c) Equal to '1'
d) Infinite
Answer: Equal to '1'
108. Consider the assertions given below
A : CDF is a monotonously increasing function
B : PDF is a derivative of CDF & is always positive
Which among them is correct according to the properties of PDF?
a) A is true & B is false
b) A is false & B is true
c) Both A & B are true but B is a reason for A
d) Both A & B are false since B is not a reason for A
Answer: Both A & B are true but B is a reason for A
109. The Joint Cumulative Density Function (CDF) _____
a) Is a non-negative function
b) Is a non-decreasing function of x & y planes
c) Is always a continuous function in xy plane
d) All of the above
Answer: All of the above
110. Which among the below mentioned standard PDFs is/are applicable to discrete random variables?
a) Gaussian distribution
b) Rayleigh distribution
c) Poisson distribution
d) All of the above
Answer: Poisson distribution
111. When do the conditional density functions get converted into the marginally density functions?
a) Only if random variables exhibit statistical dependency
b) Only if random variables exhibit statistical independency
c) Only if random variables exhibit deviation from its mean value
d) None of the above
Answer: Only if random variables exhibit statistical independency
112. Which type of standard PDFs has/ have an ability to describe an integer valued random variable concerning to the repeated trials carried /conducted in an experiment?
a) Binomial
b) Uniform
c) Both a & b
d) None of the above
Answer: Binomial
113. A random variable belongs to the category of a uniform PDF only when ______
a) It occurs in a finite range
b) It is likely to possess zero value outside the finite range
c) Both a & b
d) None of the above
Answer: Both a & b
114. What would happen if the value of term [(m-x) / (σ √2)]  increases in the expression of Guassian CDF?
a) Complementary error function also goes on increasing
b) Complementary error function goes on decreasing
c) Complementary error function remains constant or unchanged
d) Cannot predict
Answer: Complementary error function goes on decreasing
115. When is the system said to be causal as well as stable in accordance to pole/zero of ROC specified by system transfer function?
a) Only if all the poles of system transfer function lie in left-half of S-plane
b) Only if all the poles of system transfer function lie in right-half of S-plane
c) Only if all the poles of system transfer function lie at the centre of S-plane
d) None of the above
Answer: Only if all the poles of system transfer function lie in left-half of S-plane
116. Which among the below specified conditions/cases of discrete time in terms of real constant 'a', represents the double-sided decaying exponential signal?
a) a > 1
b) 0 < a < 1
c) a < -1
d) -1 < a < 0
Answer: -1 < a < 0
117. The frequency response of a digital filter is periodic in the range
a) 0<w<2Ï€
b)-Ï€<w<Ï€
C) 0<w<Ï€
d) 0<=w<=2Ï€ or -Ï€<=w<=Ï€
Answer: 0<=w<=2Ï€ or -Ï€<=w<=Ï€
118. Which property of delta function indicates the equality between the area under the product of function with shifted impulse and the value of function located at unit impulse instant?
a) Replication
b) Sampling
c) Scaling
d) Product
Answer: Sampling
119. What would be the joint probability of statistically independent events that occur simultaneously?
a) Zero
b) Not equal to zero
c) Infinite
d) None of the above
Answer: Not equal to zero
120. 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
Answer: sinusoid signals multiplied by decaying exponentials
121. An amplitude of sinc function that passes through zero at multiple values of an independent variable 'x' ______
a) Decreases with an increase in the magnitude of an independent variable (x)
b) Increases with an increase in the magnitude of an independent variable (x)
c) Always remains constant irrespective of variation in magnitude of 'x'
d) Cannot be defined
Answer: Decreases with an increase in the magnitude of an independent variable (x)
122. A system is said to be shift invariant only if______
a) a shift in the input signal also results in the corresponding shift in the output
b) a shift in the input signal does not exhibit the corresponding shift in the output
c) a shifting level does not vary in an input as well as output
d) a shifting at input does not affect the output
Answer: a shift in the input signal also results in the corresponding shift in the output
123. Which condition determines the causality of the LTI system in terms of its impulse response?
a) Only if the value of an impulse response is zero for all negative values of time
b) Only if the value of an impulse response is unity for all negative values of time
c) Only if the value of an impulse response is infinity for all negative values of time
d) Only if the value of an impulse response is negative for all negative values of time
Answer: Only if the value of an impulse response is zero for all negative values of time
124. Under which conditions does an initially relaxed system become unstable?
a) only if bounded input generates unbounded output
b) only if bounded input generates bounded output
c) only if unbounded input generates unbounded output
d) only if unbounded input generates bounded output
Answer: only if bounded input generates unbounded output
125. Which among the following are the stable discrete time systems?
1. y(n) = x(4n)
2. y(n) = x(-n)
3. y(n) = ax(n) + 8
4. y(n) = cos x(n)
a) 1 & 3
b) 2 & 4
c) 1, 3 & 4
d) 1, 2, 3 & 4
Answer: 1, 2, 3 & 4
126. An equalizer used to compensate the distortion in the communication system by faithful recovery of an original signal is nothing but an illustration of _________
a) Static system
b) Dynamic system
c) Invertible system
d) None of the above
Answer: Invertible system
127. Which block of the discrete time systems requires memory in order to store the previous input?
a) Adder
b) Signal Multiplier
c) Unit Delay
d) Unit Advance
Answer: Unit Delay
128. Which type/s of discrete-time system do/does not exhibit the necessity of any feedback?
a) Recursive Systems
b) Non-recursive Systems
c) Both a & b
d) None of the above
Answer: Non-recursive Systems
129. Which among the following belongs to the category of non-recursive systems?
a) Causal FIR Systems
b) Non-causal FIR Systems
c) Causal IIR Systems
d) Non-causal IIR Systems
Answer: Causal FIR Systems
130. Recursive Systems are basically characterized by the dependency of its output on _______
a) Present input
b) Past input
c) Previous outputs
d) All of the above
Answer: All of the above
131. What does the term y(-1) indicate especially in an equation that represents the behaviour of the causal system?
a) initial condition of the system
b) negative initial condition of the system
c) negative feedback condition of the system
d) response of the system to its initial input
Answer: initial condition of the system
132. Which type of system response to its input represents the zero value of its initial condition?
a) Zero state response
b) Zero input response
c) Total response
d) Natural response
Answer: Zero state response
133. Which is/are the essential condition/s to get satisfied for a recursive system to be linear?
a) Zero state response should be linear
b) Principle of Superposition should be applicable to zero input response
c) Total Response of the system should be addition of zero state & zero input responses
d) All of the above
Answer: All of the above
134. Which among the following operations is/are not involved /associated with the computation process of linear convolution?
a) Folding Operation
b) Shifting Operation
c) Multiplication Operation
d) Integration Operation
Answer: Integration Operation
135. A LTI system is said to be initially relaxed system only if ____
a) Zero input produces zero output
b) Zero input produces non-zero output
c) Zero input produces an output equal to unity
d) None of the above
Answer: Zero input produces zero output
136. What are the number of samples present in an impulse response called as?
a) string
b) array
c) length
d) element
Answer: length
137. Which are the only waves that correspond support the measurement of phase angle in the line spectra?
a) Sine waves
b) Cosine waves
c) Triangular waves
d) Square waves
Answer: Cosine waves
138. Double-sided phase & amplitude spectra _____
a) Possess an odd & even symmetry respectively
b) Possess an even & odd symmetry respectively
c) Both possess an odd symmetry
d) Both possess an even symmetry
Answer: Possess an odd & even symmetry respectively
139. What does the first term 'a0' in the below stated expression of a line spectrum indicate?
x(t) = a0 + a1 cos w0 t + a2 cos2 w0t +......+  b1 sin w0 t + b2 sin w0 t + .....
a) DC component
b) Fundamental component
c) Second harmonic component
d) All of the above
Answer: DC component
140. Which kind of frequency spectrum spectra is are obtained from the line spectrum of a continuous signal on the basis of Polar Fourier Series Method?
a) Continuous in nature
b) Discrete in nature
c) Sampled in nature
d) All of the above
Answer: Discrete in nature
141. Which types of Fourier Series allows to represent the negative frequencies by plotting the double-sided spectrum for the analysis of periodic signals?
a) Trigonometric Fourier Series
b) Polar Fourier Series
c) Exponential Fourier Series
d) All of the above
Answer: Exponential Fourier Series
142. What does the signalling rate in the digital communication system imply?
a) Number of digital pulses transmitted per second
b) Number of digital pulses transmitted per minute
c) Number of digital pulses received per second
d) Number of digital pulses received per minute
Answer: Number of digital pulses transmitted per second
143. As the signalling rate increases, _______
a) Width of each pulse increases
b) Width of each pulse decreases
c) Width of each pulse remains unaffected
d) None of the above
Answer: Width of each pulse decreases
144. Which phenomenon occurs due to an increase in the channel bandwidth during the transmission of narrow pulses in order to avoid any intervention of signal distortion?
a) Compression in time domain
b) Expansion in time domain
c) Compression in frequency domain
d) Expansion in frequency domain
Answer: Expansion in frequency domain
145. Why are the negative & positive phase shifts introduced for positive & negative frequencies respectively in amplitude and phase spectra?
a) To change the symmetry of the phase spectrum
b) To maintain the symmetry of the phase spectrum
c) Both a & b
d) None of the above
Answer: To maintain the symmetry of the phase spectrum
146. Duality Theorem Property of Fourier Transform states that _________
a) Shape of signal in time domain & shape of spectrum can be interchangeable
b) Shape of signal in frequency domain & shape of spectrum can be interchangeable
c) Shape of signal in time domain & shape of spectrum can never be interchangeable
d) Shape of signal in time domain & shape of spectrum can never be interchangeable
Answer: Shape of signal in time domain & shape of spectrum can be interchangeable
147. Which property of fourier transform gives rise to an additional phase shift of -2Ï€ ftd for the generated time delay in the communication system without affecting an amplitude spectrum?
a) Time Scaling
b) Linearity
c) Time Shifting
d) Duality
Answer: Time Shifting
148. What is the possible range of frequency spectrum for discrete time fourier series (DTFS)?
a) 0 to 2Ï€
b) -Ï€ to +Ï€
c) Both a & b
d) None of the above
Answer: Both a & b
149. Which among the below assertions is precise in accordance to the effect of time scaling?
A : Inverse relationship exists between the time and  frequency domain representation of signal
B : A signal must be necessarily limited in time as well as frequency domains
a) A is true & B is false
b) A is false & B is true
c) Both A & B are true
d) Both A & B are false
Answer: A is true & B is false
150. Which is are the mandatory conditions to get satisfied by the transfer function for the purpose of distortionless transmission?
a) Amplitude Response should be constant for all frequencies
b) Phase should be linear with frequency passing through zero
c) Both a & b
d) None of the above
Answer: Both a & b
151. What is are the crucial purposes of using the Fourier Transform while analyzing any elementary signals at different frequencies?
a) Transformation from time domain to frequency domain
b) Plotting of amplitude & phase spectrum
c) Both a & b
d) None of the above
Answer: Both a & b
152. A Laplace Transform exists when _____
A. The function is piece-wise continuous
B. The function is of exponential order
C. The function is piecewise discrete
D. The function is of differential order
a) A & B
b) C & D
c) A & D
d) B & C
Answer: A & B
153. Which among the following assertions represents a necessary condition for the existence of Fourier Transform of discrete time signal (DTFT)?
a) Discrete Time Signal should be absolutely summable
b) Discrete Time Signal should be absolutely multipliable
c) Discrete Time Signal should be absolutely integrable
d) Discrete Time Signal should be absolutely differentiable
Answer: Discrete Time Signal should be absolutely summable
154. What is the nature of Fourier representation of a discrete & aperiodic signal?
a) Continuous & periodic
b) Discrete & aperiodic
c) Continuous & aperiodic
d) Discrete & periodic
Answer: Continuous & periodic
155. Which property of periodic signal in DTFS gets completely clarified identified by the equation x (n – n0)?
a) Conjugation
b) Time Shifting
c) Frequency Shifting
d) Time Reversal
Answer: Time Shifting
156. Where is the ROC defined or specified for the signals containing causal as well as anti-causal terms?
a) Greater than the largest pole
b) Less than the smallest pole
c) Between two poles
d) Cannot be defined
Answer: Between two poles
157. Which mathematical notation specifies the condition of periodicity for a continuous time signal?
a) x(t) = x(t +T0)
b) x(n) = x(n+ N)
c) x(t) = e-αt
d) None of the above
Answer: x(t) = x(t +T0)
158. In C6X processor, which external devices gets acquires an interface support by EMIF peripheral?
a) Synchronous burst
b) Asynchronous devices
c) Externally shared memory devices
d) All of the above
Answer: All of the above
159. Two vectors a, b are orthogonal if
a) <a,b> = 0
b) <a,b> = <a,b>
c) <a,b> = 1
d) <a,b> = - <a,b>
Answer: <a,b> = 0
160. Superposition of signals in a linear system refers to the
a) Output that is product of all the signals
b) Output that is sum of all the signals
c) Output that is of highest amplitude of all the signals
d) Output that is of largest spectrum of all the signals
Answer: Output that is sum of all the signals
161. The scaling of a sequence x[n] by a factor α is given by
a) y[n] = α [x[n]]2
b) y[n] = α x[n2]
c) y[n] = α x[n]
d) y[n] = x[n]x[-n]
Answer: y[n] = α x[n]
162. DFT is applied to
a) Infinite sequences
b) Finite discrete sequences
c) Continuous infinite signals
d) Continuous finite sequences
Answer: Finite discrete sequences
163. The filtering is performed using DFT using
1) Limited size or blocks of data
2) Small memory size
3) Large memory size
4) Large segments of data
a) 1, 2 and 3 are correct
b) 3 and 4 are correct
c) 1 and 2 are correct
d) All the four are correct
Answer: 1 and 2 are correct
164. In Overlap-Add Method with linear convolution of a discrete-time signal of length L and a discrete-time signal of length M, for a length N, zero padding should be of length
a) L, M > N
b) L, M = N
c) L, M < N
d) L, M < N2
Answer: L, M < N
165. Discrete cosine transforms (DCTs) express a function or a signal in terms of
a) Sum of cosine functions oscillating at different frequencies
b) Sum of cosine functions oscillating at same frequencies
c) Sum of cosine functions at different sampling intervals
d) Sum of cosine functions oscillating at same sampling intervals
Answer: Sum of cosine functions oscillating at different frequencies
166. A system is said to be unstable if
a) None of the poles of its transfer function is shifted to the right half of s-plane
b) At least one zero of its transfer function is shifted to the right half of s-plane
c) At least one pole of its transfer function is shifted to the right half of s-plane
d) At least one pole of its transfer function is shifted to the left half of s-plane
Answer: At least one pole of its transfer function is shifted to the right half of s-plane
167. A system is said to be marginally unstable if
a) None of its zeros of its transfer function lies on the jω axis of s-plane
b) At least one zero of its transfer function lies on the jω axis of s-plane
c) None of its poles of its transfer function lies on the jω axis of s-plane
d) At least one pole of its transfer function lies on the jω axis of s-plane
Answer: At least one pole of its transfer function lies on the jω axis of s-plane
168. The nonlinear difference equations are solved using
a) Iterative method
b) Cobweb model
c) Phase diagram
d) Power series method
Answer: Phase diagram
169. Correlation is used for
1) Computation of average power in waveforms
2) Climatography
3) Identification of binary code word in PCM systems
4) Quantization
a) 1, 2 and 3 are correct
b) 1 and 2 are correct
c) 2 and 3 are correct
d) All the four are correct
Answer: 1, 2 and 3 are correct
170. The Chebyshev filters have
1) Flat pass band
2) Flat stop band
3) Equiripple pass band
4) Tapering stop band
a) 1 and 2 are correct
b) 2 and 4 are correct
c) 2 and 3 are correct
d) All the four are correct
Answer: 2 and 3 are correct
171. The Elliptic filters have
1) Flat pass band
2) Flat stop band
3) Equiripple pass band
4) Equiripple stop band
a) 1 and 2 are correct
b) 3 and 4 are correct
c) 2 and 3 are correct
d) All the four are correct
Answer: 3 and 4 are correct
172. The effects caused due to finite word lengths are
1) Coefficient quantization error
2) Adder overflow limit cycle
3) Round off noise
4) Limit cycles
a) 1, 2 and 3 are correct
b) 1 and 3 are correct
c) 1 and 4 are correct
d) All the four are correct
Answer: All the four are correct
173. The error in the filter output that results from rounding or truncating calculations within the filter is called
a) Coefficient quantization error
b) Adder overflow limit cycle
c) Round off noise
d) Limit cycles
Answer: Round off noise.
174. Consider the assertions given below. Which among them is an advantage of FIR Filter?
a) Necessity of computational techniques for filter implementation
b) Requirement of large storage
c. Incapability of simulating prototype analog filters
d) Presence of linear phase response
Answer: Presence of linear phase response
175. For a linear phase filter, if Z1 is zero then what would be the value of Z1-1 or 1/ Z1?
a) Zero
b) Unity
c) Infinity
d) Unpredictable
Answer: Zero
176. In FIR filter design, which among the following parameters is are separately controlled by using Kaiser window?
a) Order of filter (M)
b) Transition width of main lobe
c) Both a and b
d) None of the above
Answer: Both a and b
178. Which window function is also regarded as 'Raised-cosine window'?
a) Hamming window
b) Hanning window
c) Barlett window
d) Blackman window
Answer: Hanning window
179. In Barlett window, the triangular function resembles the tapering of rectangular window sequence _______ from the middle to the ends.
a) linearly
b) elliptically
c) hyperbolically
d) parabolically
Answer: linearly
180. In Gibb's phenomenon, the ringing effect is predominantly present near the ______ .
a) bandgap
b) bandedge
c) bandwidth
d) bandshell
Answer: bandedge
181. How is are the roundoff errors reduced in the digital FIR filter?
a) By representation of all products with double-length registers
b) By rounding the results after acquiring the final sum
c) Both a and b
d) None of the above
Answer: Both a and b
182. In linear phase realization, equal valued coefficients are taken common for reducing the requisite number of ________.
a) adders
b) subtractors
c) multipliers
d) dividers
Answer: multipliers
183. Which filters exhibit their dependency upon the system design for the stability purpose?
a) FIR
b) IIR
c) Both a and b
d) None of the above
Answer: IIR
184. In FIR filters, which among the following parameters remains unaffected by the quantization effect?
a) Magnitude Response
b) Phase Characteristics
c) Both a and b
d) None of the above
Answer: Phase Characteristics
185. In the frequency response characteristics of FIR filter, the number of bits per coefficient should be _________in order to maintain the same error.
a) Increased
b) Constant
c) Decreased
d) None of the above
Answer: Increased
186. In cascade form of realization, how many bits should be used to represent the FIR filter coefficients in order to avoid the quantization effect on filter coefficients?
a) 5 to 10
b) 12 to 14
c) 20 to 24
d) 28 to 40
Answer: 12 to 14
187. Consider the assertions (steps) given below. Which among the following is a correct sequence of designing steps for the sampling rate converters?
A. Computation of decimation interpolation factor for each stage.
B. Clarification of anti-aliasing anti-imaging filter requirements.
C. Designing of filter at each stage.
D. Calculation of optimum stages of decimation/ interpolation yielding maximum efficient implementation.
a) A, B, C, D
b) C, A, D, B
c) D, A, B, C
d) B, D, A, C
Answer: B, D, A, C
188. For designing a multirate LPF with passband 0 to 50 Hz, stopband 60 to 280 Hz, stopband deviation 0.001, passband deviation 0.01 and sampling frequency (fs) = 400 Hz, what would be the value of normalized transition width?
a) 0.025 Hz
b) 1.25 Hz
c) 1.50 Hz
d) 2.6 Hz
Answer: 0.025 Hz
189. In polyphase filters, the subfilters which share a common delay line results in the reduction of the storage requirement by factor ______
a) 1
b) 2
c) 3
d) 4
Answer: 3
190. In DSP Processor, what kind of queuing is undertaken executed through instruction register and instruction cache?
a) Implicate
b) Explicate
c) Both a and b
d) None of the above
Answer: Implicate
191. In polyphase filter, which kind of realization is are adopted for three subfilters possessing coefficients?
a) Cascade
b) Parallel
c) Direct
d) All of the above
Answer: Parallel
192. How is the sampling rate conversion achieved by factor I/D?
a) By increase in the sampling rate with (I)
b) By filtering the sequence to remove unwanted images of spectra of original signal
c) By decimation of filtered signal with factor D
d) All of the above
Answer: All of the above
194. Program Sequence plays a crucial role in maintaining the track of ___________
a) Program counter increment
b) Conditional branching & looping
c) Subroutine & interrupt handling
d) All of the above
Answer: All of the above
195. How is the operating level of sampling rate for the subfilters involved in the polyphase filters?
a) Low
b) Moderate
c) High
d) None of the above
Answer: Low
196. In TMS 320 C6x processor architecture, which functional unit is adopted for transferring the data from register to and from control register?
a) L2
b) M2
c) S2
d) D2
Answer: S2
197. In TMS 320 C6x processor architecture, which operations is are performed by 'M' functional unit?
a) Bit expansion
b) Bit interleaving & deinterleaving
c) Rotation & Variable shifting
d) All of the above
Answer: All of the above
198. Which peripheral on C 6 X processor allows buffering of serial samples in memory by port automatically & especially with an assistance of EDMA controller?
a) Boot Loader
b) HPI
c) EMIF
d) McBSP
Answer: McBSP
199. One dimensional signal is a function of
a) Multiple independent variables
b) Single independent variable
c) Multiple dependent variables
d) Single dependent variable
Answer: Single independent variable
200. IIR filters are designed by considering all the
a) Infinite samples of frequency response
b) Finite samples of impulse response.
c) Infinite samples of impulse response.
d) None of the above.
Answer: Infinite samples of impulse response.


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