Transcript q1ppt

DEPARTMENTT OF ECE
TECHNICAL QUIZ-1
AY-2015 -2016
Sub Code/Name: EC6502/Principles of digital
Signal Processing
Topic: Unit 1 & Unit 3
Sem/year: V/III
1) What is the condition to perform circular convolution of two
sequences?
a) length must be equal
b) length of one must be greater
c) length of one must be smaller
d) both b and c
2. The DFT of a signal x(n) of length N is X(k). When X (k) is
given and x (n) is computed from it, What is the length of
x(n) ?
a)is increased to infinity
b) remains N
c) becomes 2N – 1
d) becomes N
3. What is the length of output sequence for linear convolution
if L=3 and M=5?
a) 5
b) 6
c) 7
d) 8
4. What is the length of output sequence for circular
convolution if L=3 and M=5?
a)5
b) 6
c) 7
d) 8
5. Which signals can have only a limited number of values?
a) Analog
b) b) Digital
c) (a)or (b)
d) None of the above
6. How many adders are required to realize a 32 point DFT?
a) 992
b) 1024
c) 4096
d) 2048
7. How many multiplications are required to realize a 32 point
DFT?
a) 992
b) 1024
c) 4096
d) 2048
8. What is the conversion of CT signals into a DT signals ?
a) Sampling
b) Quantization
c) Coder
d) ADC
9. What is the conversion of DT signals into a discrete value
signals?
a) Sampling
b) Quantization
c) Coder
d) ADC
10. For DIT-FFT, the input must be in which order?
a) Normal order
b) b) Bit reverse order
c) Reverse order
d) Complement form
11. How many of stages in 64-point FFT ?
a)3
b)4
c)5
d)6
12. How many number of stages in 512-point FFT?
a) 5
b) 7
c) 9
d) 11
13. What is the need of Convolution?
a)The impulse response of an LTI System
b) Frequency response of a System
c) The time response of a LTI system
d)The phase response of a LTI system
15. When the sequence is circularly shifted in time domain by
‘m’ samples i.e. x((n-m))N then on applying DFT, what it is
equivalent multiply sequence in frequency domain ?
16. What is the result of Multiplication of sequence in time
domain, on apply DFT, it corresponds to circular convolution
in frequency domain ?
a) x1(n) x2(n) X1(K)*X2(K)
b) x1(n) x2(n) X1(K)X2(K)
c) x1(n) * x2(n) X1(K)
X2(K)
d) x1(n) x2(n) X1(K)X2(K)
17. What is the length of an output sequence for linear
convolution of two sequences N1 and N2?
a) N1 – N2 +1
b) b) N1 + N2 –1
c) N1 + N2 +1
d) 2N1 – N2 +1
18. What is the number of sets or sections of butterflies in each
stage?
a) 2N
b) n log n
c) log n
d) n/2 log n
19. How many number of complex multiplications are required
to calculate Radix-2 FFT?
a) 2N
b) n log n
c) log n
d) n/2 log n
20. What is zero padding?
a) Appending zeros to a sequence
b) decreasing zeros to a sequence
c) adding ones to a sequence
d) subtracting zeros
21. What is the Conversion of a continuous time signal into a
digital value produces?
a) Input quantization error
b) output quantization error
c) co-efficient quantization error
d) product quantization error
22. What is the p(e) for two’s complement truncation ?
a) q
b) 1-q
c) 1/q
d) q/2
23. What is the two’s complement of negative number when all
the bits of the positive number and adding one ?
a)Adding, MSB
b) complementing ,least significant bit
c) subtracting, MSB
d) all the above
24. What are the Common methods of quantization?
a) Rounding
b) b) truncation
c) aliasing
d) both a & b
25. From the assumptions of the effects of rounding in digital
filter error sequence, what type of signal e(n) is ?
a) Thermal noise
b) shot noise
c) white noise
d) Attenuation
26. How many quantization errors in finite word length
register?
a) 1
b) 2
c) 3
d) 4
27. What realization is less sensitive to process of quantization?
a) Cascade
b) Parallel form
c) Direct form-1
d)Direct form-2
28. What are the methods used to prevent over flow?
a) Limit cycle, saturation arithmetic
b) overflow limit cycle, saturation arithmetic
c) saturation arithmetic; signal scaling
d) none of the above
29. What is A/D converter output?
a) x(n)+ e(n)
b) x(n)- e(n)
c) e(n)
d) x(n)
30. In one’s compliment representation, what is the error for
truncation of positive values of the mantissa?
a) 0>=mt-m>-2^b
b) 0>=mt >-2^b
c) 0>= m>-2^b
d) mt-m>-2^b
31. What is the application of DFT in DSP ?
a) Spectral analysis
b) digital filtering
c) both a & b
d) none of the above
32. What is the Finite precision representation
of number in a digital system ?
a) Finite word length
b) Register word length
c)Floating point
d) Fixed point
33. When the quantization and coding will introduce, what is
the name of the error in input data?
a) Error due to quantization of filter coefficient
b) Error due to quantization of input data
c) Error due to quantization of input data by ADC
d) Limit cycles
34. How many quantization levels in 8-bit register word length?
a) 128
b) 256
c) 512
d) 64
35. What operation leads to truncation and rounding error in
floating point representation?
a) Multiplication
b) b) Addition
c) Multiplication and addition
d) Subtraction
36. What operation leads to truncation and rounding error in
fixed point representation?
a) Multiplication
b) Addition
c) Multiplication and addition
d) Subtraction
37. In which of the following, Overflow is rare?
a) Mantissa
b) Exponent
c) Fixed point
d) Floating point
38. What is the process of reducing size of binary number by
discarding all bits less significant?
a) Rounding
b) Truncation
c) Quantization
d) None
39. When a stable IIR digital filter is excited by a finite input
sequence what is the output will ideally decay ?
a) 0
b) 1
c) 2
d) 3
40. What are the process rounding?
a) Truncation and addition
b) Discarding and addition
c) Truncation and subtraction
d) Truncation
41. What is the Error due to representation of sampled signal
by a fixed number of digital levels?
a) Saturation error
b) Quantization error
c) Step size error
d) Truncation error
42. What is the Error occurs when analog signal exceed the
range of ADC?
a) Saturation error
b) Quantization error
c) Step size error
d) Truncation error
43. What is the Quantization step size for 2’s complement?
44. What is the Steady state input noise power?
45. What is the error due to quantization in multiplication ?
a) Error due to quantization of filter coefficient
b) Error due to quantization of input data
c) Error due to quantization of input data by ADC
d) Limit cycles
46. What is the amplitude of the outputs during limit cycles are
confined to range of values ?
a) Pass band
b) Stop band
c) Dead band
d) None
47.What is the nature of IIR digital filter?
a)Recursive
b) Non Recursive
c)Reversive
d)Non Reversive
48. Number of complex additions required to calculate Radix –
2 FFT is
49. What type of signals can have only a limited number of
values?
a)Analog
b)Digital
c)(a) or (b)
d)Discrete
50. Which of the following is having more computation?
a)DIT
b) DIF
c) a and b
d) DFT