IMPORTANT QUESTIONS - EC6502 Principles of Digital Signal Processing-4
Question Bank
UNIT IV
Part A
- What do you understand by a fixed point number?
(Apr-2011)
- Express the fraction 7/8 and -7/8 in sign
magnitude, 2’s complement and 1’s complement.
- What are the quantization errors due to finite
word length registers in digital filters?
- What are the different quantization methods?
- What are the different types of fixed point
number representation?
- What do you understand by sign-magnitude
representation?
- What do you understand by 2’s
complement representation?
- Write an account on floating point
arithmetic?
- What is meant by block floating point
representation? What are its advantages?
- What are advantages of floating point
arithmetic? (Nov-2011)
- Compare the fixed point and floating point
arithmetic.
- What are the three quantization errors due to
finite word length registers in digital filters?
- How the multiplication and addition are carried
out in floating point arithmetic?
- Brief on co-efficient inaccuracy.
- What do you understand by input quantization
error? (Nov-2013)
- What is product quantization error? (Nov-2010)
- What is meant by A/D conversion mode?
- What is the effect of quantization on pole locations?
- What are
the assumptions made concerning the statistical independence of various noise sources that occur in
realizing the filter?
- What is zero input limit cycle overflow
oscillation (Nov-2011)
- What is meant by limit cycle oscillations? (Nov-2012,Apr-2011)
- Explain briefly the need for scaling digital
filter implementation?
- Why rounding is preferred than truncation in
realizing digital filter?
- Define the deadband of the filter? (Nov-2014,May-2012)
- Determine the dead band of the filter with pole
at 0.5 and the number of bits used
for quantization is 4(including sign bit)
- Draw the quantization noise model for a first
order IIR system
- What is meant by rounding? Draw the pdf of
round off error
- What is meant by truncation? Draw the pdf of
round off error (Nov-2010)
- What do you mean by quantization step size?
- What is scaling?(Nov-2014)
- State the methods used to prevent
overflow.(Nov-2013)
- Find the quantization step size of the
quantizer with 3 bits
- Give the expression for signal to quantization
noise ratio and calculate the
improvement with an increase of 2 bits to the existing bit.
- Express the following binary numbers in decimal
(a)
(100111.1110)2 (b)
(101110.1111)2 (c)
(10011.011)2
PART-B
- Draw the quantization noise model for a second
order system and explain and find
its steady state output noise variance
- Consider the transfer function H(z)=H1(z)H2(z)
where
Find the output round off noise power. Assume a1=0.5 and a2=0.6 and find out the output round off noise power. - Find the effect of coefficient quantization on
pole locations of the given second order IIR system when it is realized in
direct form I and in cascade form. Assume a word length of 4-bits through
truncation.
- Explain the characteristics of Limit cycle
oscillations with respect to the system described by the differential
equations. y(n)=0.95y(n-1)+x(n) and determine the dead band of the filter.
- i) Describe
the quantization errors that occur in rounding and truncation in 2’s complement.
ii) Draw a
sample/hold circuit and explain its operation.(Nov-2014,May-2014,Nov-2010,May-2011)
- Express the following decimal numbers in binary
form
(a)
525 (b) 152.1875 (c) 225.3275
- Express the decimal values 0.78125 and -0.1875
in (i) 1’s complement form (ii)sign magnitude form (iii) 2’s complement
form.
- Express the decimal values -6/8 and 9/8 in (i) Sign magnitude form
(ii) 1’s complement form and (iii) 2’s complement form
- Study the limit cycle behavior of the following
systems
(a)
y(n)
= 0.7y(n-1) + x (n)
(b)
y(n)
= 0.65y(n-2) + 0.52y (n-1) + x (n)
- Derive the quantization input noise power and
determine the signal to noise ratio of the system. (Nov-2014)
- Derive the truncation error and round off error
noise power and compare both errors.
- Explain product quantization error and
coefficient quantization error with examples (Nov-2014,April-2011,May-2014)
- Derive the scaling factor so that prevents the
overflow limit cycle oscillations in a second order IIR system.
- The input to the system y(n)=0.999y(n-1)+x(n)
is applied to an ADC. What is the power produced by the quantization noise
at the output of the filter if the input is quantized to
(a) 8 bits (b) 16 bits
- Convert the following decimal numbers into binary:
(a) (20.675) (b)
(120.75)
- Find the steady state variance of the noise in
the output due to quantization of
input for the first order filter y(n)=ay(n-1) + x(n)
- The output of an A/D is fed through a digital system whose
system function is
H(z)=0.6z/z-0.6.
Find the output noise power of the digital system=8 bits.
- a. Write a short note on limit cycle
oscillation. (Nov-2010,Nov-2011)
b. Explain in detail about signal scaling. ((Nov-2011,May-2012)
- A digital system is characterized by the
difference equation
y(n)=0.95y(n-1)+x(n).
Determine the dead band of the system when x(n)=0 and y(-1)=13
- Two first order filters are connected in
cascaded whose system functions of
the
individual
sections are H1(z)=1/(1-0.8z-1) and H2(z)=1/(1-0.9z-1
). Determine the
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