Sunday, 19 August 2012
Saturday, 18 August 2012
dsp notes
Part B
1.
Determine the DFT
of the sequence
x(n) =1/4, for 0<=n <=2
0,
otherwise
Ans: The N point DFT of the sequence x(n) is defined as
N-1
x(k)= ∑ x(n)e-j2πnk/N K=0,1,2,3,…N-1 n=0
x(n) = (1/4,1/4,1/4)
X(k) = ¼ e-j2πk/3[1+2cos(2πk/3)] where k= 0,1,……….,N-1
2. Derive the DFT
of
the sample data sequence x(n) = {1,1,2,2,3,3}and compute the corresponding
amplitude and phase spectrum.
Ans: The N point DFT of the sequence x(n) is defined as
N-1
X(k)= ∑ x(n)e-j2πnk/N K=0,1,2,3,…N-1 n=0
X(0) = 12
X(1) = -1.5
+ j2.598
X(2) = -1.5
+ j0.866
X(3) = 0
X(4) = -1.5
– j0.866
X(5) =-1.5-j2.598
X(k) = {12,
-1.5 + j2.598, -1.5 + j0.866,0,
-1.5 – j0.866, -1.5-j2.598}
|X(k)|={12,2.999,1.732,0,1.732,2.999}
∟X(k)={0,- π/3,- π/6,0, π/6, π/3}
3.Given x(n) = {0,1,2,3,4,5,6,7} find X(k) using DIT FFT
algorithm.
Ans: Given N = 8
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Using butterfly diagram
X(k) = {28,-4+j9.656,-4+j4,-4+j1.656,-4,-4-j1.656,-4-j4,-4-j9.656}
4.Given
X(k) = {28,-4+j9.656,-4+j4,-4+j1.656,-4,-4-j1.656,-4-j4,-4-j9.656}
,find x(n)
using
inverse DIT FFT algorithm.
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x(n) = {0,1,2,3,4,5,6,7}
5.Find the
inverse DFT
of
X(k) = {1,2,3,4} Ans: The inverse DFT is defined
as
N-1
x(n)=(1/N )
∑ x(k)ej2πnk/N n=0,1,2,3,…N-1 k=0
x(0) = 5/2
x(1) = -1/2-j1/2 x(2) = -1/2
x(3) = -1/2+j1/2
x(n) = {5/2,
-1/2-j1/2, -1/2, -1/2+j1/2}
6. Design an ideal
low pass filter with a
frequency response Hd(e jw) =1
for
–
∏/2<=w<=∏/2
find
the value of h(n) for N=11
find H(Z) plot magnitude
response a. Find
h(n) by IDTFT
b. Convert h(n) in to a
fine length by truncation
c.
H(0)=1/2,
0 otherwise
h(1)=h(-1)=0.3183 h(2)=h(-2)=0 h(3)=h(-3)= -0.106
h(4)=h(-4)=0 h(5)=h(-5)=0.06366
d. Find the transfer function H(Z) which is not realizable conver in to realizable by multiplying by z-(N-1/2)
e. H’(Z) obtained is 0.06366-0.106z-2+.3183Z-4+.5Z-5+.3183Z-6-.106Z-8+0.06366Z-
10
f. Find
H (e jw) and
plot amplitude response
curve.
7. Design an ideal
low pass filter with a
frequency response Hd(e jw) =1
for
–
∏/4<=|w|<=∏
find the value of h(n) for N=11 find
H(Z)
plot magnitude response
0 otherwise
g. Find
h(n) by IDTFT
h. Convert h(n) in to a
fine length by truncation
i. H(0)=0.75
h(1)=h(-1)=-.22 h(2)=h(-2)=-.159
h(3)=h(-3)= -0.075 h(4)=h(-4)=0
h(5)=h(-5)=0.045
j. Find the transfer function H(Z) which is not realizable conver in to realizable by multiplying by z-(N-1/2)
k. H’(Z) obtained is 0.045-0.075z-2 -.159
Z-3-0.22Z-4+0.75Z-5-.22Z-6 -0.159Z-7 -.
075Z-8+0.045Z-10
l. Find
H (e jw) and
plot amplitude response
curve.
8. Design band pass
filter with a frequency response Hd(e jw) =1 for –∏/3<=|w|<=2∏/3
0 otherwise
find the value of h(n) for N=11 find
H(Z)
plot magnitude response
m. Find h(n) by IDTFT
n. Convert
h(n) in to a fine length
by
truncation
o. Find the transfer function H(Z) which is not realizable conver in to realizable by multiplying by z-(N-1/2)
p. H’(Z) obtained
Find H (e jw) and plot amplitude response curve.
9. Design band reject
filter with a frequency response Hd(e jw) =1 for ∏/4<=|w|<=3∏/4
0 otherwise
find the value of h(n) for N=11 find
H(Z)
plot magnitude response
q. Find
h(n) by IDTFT
r. Convert
h(n) in to a fine length
by
truncation
s. Find
the transfer function
H(Z) which
is not realizable conver in
to realizable by multiplying by z-(N-1/2)
t. H’(Z) obtained
Find H (e jw) and plot amplitude response curve.
10. Derive the condition
of FIR filter to be
linear in phase. Conditions
are
Group
delay and
Phase delay should be constant
And
And show the condition is satisfied
11Derive the expression for steady state I/P Noise Power and Steady state O/P Noise
Power.
Write the derivation.
12
Draw the product
quantatization model
for
first order and second order filter
Write the difference equation
and draw the noise model.
13 For the second
order filter Draw the direct form II realization
and find the scaling
factor S0 to avoid over flow
Find the scaling factor from
the formula
1+r2
I= ---------------------------------------
(1-r2)(1-2r2cos2ø
=r4)
14 Explain Briefly about various number representation
in digital computer.
1 Fixed point
2 Floating point
3 Block
floating point
Signed
magnitude represenation
1’s Complement
2’s Complement
etc
15 Consider the transfer function H(Z)=H1(Z)H2(Z) where H1(Z) =1/1-a1Z-1
H2(z) =1/ 1-a2Z-1
Find
the o/p Round of noise power Assume
a1=0.5 and a2= 0.6 and find
o.p round
off
noise power.
Draw the
round of Noise Model. By using residue method find
σ01
By using residue method find
σ 02
= σ 01 2+ σ 02
2
2 –2b (5.43) Ans:
12
16.Explain
the architecture of DSP processor .
Diagram. & explanation.
17.Describe briefly the different methods
of power spectral
estimation?
1. Bartlett
method
2. Welch
method
3. Blackman-Tukey method
and its derivation.
18.what is meant by A/D conversion noise. Explain in detail?
A DSP contains
a device,
A/D converter that
operates on the analog input x(t) to
produce xq(t) which
is binary sequence of 0s
and
1s.
At first
the signal x(t) is sampled at
regular intervals
to produce a sequence x(n) is of infinite precision.
Each sample x(n) is
expressed
in terms of a finite number of bits
given
the sequence xq(n). The difference signal e(n)=xq(n)-x(n) is called A/D conversion noise.
+ derivation.
19 onsider the transfer function
H(Z)=H1(Z)H2(Z) where H1(Z) =1/1-a1Z-1
H2(z) =1/ 1-a2Z-1
Find
the o/p Round of noise power Assume
a1=0.7 and a2= 0.8and find
o.p round
off
noise power.
Draw the
round of Noise Model. By using residue method find
σ01
By using residue method find
σ 02
= σ 01 2+ σ 02
2
20.Given X(k) = {1,1,1,1,1,1,1,1,} ,find x(n) using inverse DIT FFT
algorithm.
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Find x(n)
21.Find the
inverse DFT of X(k) = {3,4,5,6} Ans: The inverse DFT is defined
as
N-1
x(n)=(1/N ) ∑ x(k)ej2πnk/N n=0,1,2,3,…N-1 k=0
22. Explain various addressing
modes of TMS processor.
Immediate. Register
Register indirect
Indexed
& its
detail
explanation.
23 Derive the expression for steady state I/P Noise Variance and Steady state O/P
Noise Variance
Write the derivation.
24. Explain briefly the periodogram method
of power spectral estimation?
Write the derivation
with explanation.
25. Explain various
arithmetic instruction
of TMS processor.
All arithmetic instruction
with explanation.
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