# Digital Signal Processing - ND09 5th EC9304

ANNA UNIVERSITY – COIMBATORE
B.E.\B.TECH DEGREE EXAMINATION - DECEMBER 2009
FIFTH SEMESTER - 5th
ELECTRONICS and COMMUNICATION ENGG.
DIGITAL SIGNAL PROCESSING - EC9304

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PART A-(2*20=40)

1. Define twiddle factor of FFT.
2. The first five 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. Calculate the number of multiplications needed in the calculation of DFT and FFT with 64-point sequence.
4. What is zero padding. What are its uses.
5. What are the desirable and undesirable features of FIR filters.
6. What is the necessary and sufficient condition for linear phase characteristics in FIR filter.
7. Define Gibb’s phenomenon.
8. Draw the direct form I structure for the second order system function
H(z)= b0+b1z-1+b2z-2
1+a1z-1+a2z-2
9. Find the digital filter transfer function H(z) by using impulse invariant method.
for the analog transfer function H(s)=1/(S+2).
10. Give any two properties of Butterworth filter.
11. What is warping effect. What is the effect on magnitude and phase responses.
12. Mention any two procedures for digitizing the transfer function of an analog filter.
13. What are the quantization errors due to finite word length registers in digital filters.
14. What is overflow oscillations. What are the methods to prevent it.
15. Define 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 6 bits, compute the quantization error due to truncation.
17. What are the addressing modes of TMS320C50.
18. What is the advantage of Harvard architecture of TMS320 series.
19. What is the different buses of TMS320C50.
20. What are the arithmetic instructions of C50.

PART B-(5*12=60)

21. A) Find the 8 point DFT of the given 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 following two 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 following system function using minimum number of multipliers (4)
H(z)=1+1z-1+1z-2+1z-3+1z-4+z-5
3 4 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) 8 bits (ii) 16 bits. (8)
B) Compare fixed point and floating point arithmetic. (4)

25. A) With a neat block diagram explain 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). Assume a1=0.5 and a2=0.6 and find the output round off noise power.

28. A) Calculate the DFT of the sequence X(n) = {1,1,-2,-2}. (6)
B) Find 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.