Anna University Coimbatore 2009 B.E Electronics & Communication Engineering Anna university – coimbatore-digital signal processing - Question Paper

ANNA UNIVERSITY – COIMBATORE
B.E.\B.TECH.DEGREE-EXAMINATION-DECEMBER 2009
FIFTH SEMESTER-ELECTRONICS & COMMUNICATION ENGG.
DIGITAL SIGNAL PROCESSING

PART A-(2*20=40)

1. describe twiddle factor of FFT.
2. The 1st 5 DFT coefficients of a sequence x(n) are X(0)=20, X(1)=5+j2, X(2)=0, X(3)=0.2+j0.4, X(4)=0. Determine the remaining DFT coefficients.
3. compute the number of multiplications needed in the computation of DFT and FFT with 64-point sequence.
4. What is zero padding. elaborate its uses.
5. elaborate the desirable and undesirable features of FIR filters.
6. What is the necessary and sufficient condition for linear phase characteristics in FIR filter.
7. describe Gibb's phenomenon.
8. Draw the direct form I structure for the 2nd order system function
H(z)= b0+b1z-1+b2z-2
1+a1z-1+a2z-2
9. obtain the digital filter transfer function H(z) by using impulse invariant method.
for the analog transfer function H(s)=1/(S+2).
10. provide any 2 properties of Butterworth filter.
11. What is warping effect. What is the effect on magnitude and phase responses.
12. Mention any 2 procedures for digitizing the transfer function of an analog filter.
13. elaborate the quantization errors due to finite word length registers in digital filters.
14. What is overflow oscillations. elaborate the methods to prevent it.
15. describe a Deadband of a filter.
16. The filter coefficient H=-0.673 is represented by sign magnitude fixed point arithmetic. If the word length is six bits, calculate the quantization fault due to truncation.
17. elaborate the addressing modes of TMS320C50.
18. What is the advantage of Harvard architecture of TMS320 series.
19. What is the various buses of TMS320C50.
20. elaborate the arithmetic instructions of C50.

PART B-(5*12=60)

21. A) obtain the eight point DFT of the provided sequence x(n)={0,1,2,3,4,5,6,7} using Dif radix-2 FFT algorithm. (8)
B) Perform the circular convolution of the subsequent 2 sequences using matrix method. X1(n)={2,1,2,1} , X2(n)={1,2,3,4} (4)


22. A) Design an idea Hilbert transformer having frequency response
H(ej?)=j for -p=?=0.
= - j for 0=?=p. Using rectangular window for N=11. (8)
B) Realize the subsequent system function using minimum number of multipliers (4)
H(z)=1+1z-1+1z-2+1z-3+1z-4+z-5
3 four 4 3
23. Design a digital Butter-worth filter satisfying the constraints. 0.707=¦H(ej?)¦= for 0=?= p/2.
¦H(ej?)¦=0.2 for 3p/4=?= p.
With T=1 sec using bi-linear transformation.
24. A) 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 (i) eight bits (ii) 16 bits. (8)
B) Compare fixed point and floating point arithmetic. (4)
25. A) With a neat block diagram discuss in detail the architecture of TMS320C50. (8)
B) Write short notes on pipelining. (4)
26. Design a high pass filter with Hamming window with a cut-off frequency of 1.2 radians/sec and N=9.
27. Consider the transfer function H(z)=H1(z) where H1(z)=1/(1-a1z-1) and H2(z)=1/(1-a2z-1). presume a1=0.5 and a2=0.6 and obtain the output round off noise power.
28. A) compute the DFT of the sequence X(n) = {1,1,-2,-2}. (6)
B) obtain the output y(n) of a filter whose impulse response is h(n)= {1,1,1} and input signal x(n)= {3,-1,0,1,3,2,0,1,2,1} using overlap save method.

Earning:   Approval pending.