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Reg. No. :

B.E./B.Tech. DEGREE EXAMINATION, APRIL/MAY 2011

Fifth Semester

Electrical and Electronics Engineering

EC 2314 — DIGITAL SIGNAL PROCESSING

(Regulation 2008)

Time : Three hours Maximum : 100 marks

Answer ALL questions

PART A — (10 × 2 = 20 marks)

1. Define sampling theorem.

2. What is known as Aliasing?

3. What is meant by ROC?

4. Obtain the Discrete Fourier series coefficients of wnnx cos)( = .

5. What is the relation between DFT and Z transform?

6. Draw the butterfly diagram for DITFFT.

7. What are the special features of FIR filters?

8. What is meant by prewarping?

9. Mention the features of DSP processor.

10. What is the condition for linear phase in FIR filters?

PART B — (5 × 16 = 80 marks)

Question Paper Code : 11295

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11295 2

11. (a) (i) Check whether the following is linear, time invariant, casual and

stable )1()()( ++= nnxnxny . (8)

(ii) Check whether the following are energy or power signals.

(1) )(2

1)( nunx

n

=

(2) njwAenx 0)( = . (8)

Or

(b) (i) Describe in detail the process of sampling and quantization.

Also determine the expression for quantization liner. (10)

(ii) Check whether the following are periodic

(1) )3cos()( nnx π=

(2) )3sin()( nnx = . (6)

12. (a) (i) Determine the Z transform of

(1) 0( ) cos ( )nx n a w n u n= . (5)

(2) )(3)( nunx n= . (3)

(ii) Obtain )(nx for the following :

21 52.052.11

1)(

−− +−=zX

for ROC : | | 1, | | 0.5z z> < , 1||5.0 << z . (8)

Or

(b) (i) Determine the linear convolution of the following sequences

}1,3,2,1{)(1 =nx ↑

−= }1,1,2,1{)(2 nx . (6)

(ii) Obtain the system function and impulse response of the

following system )1()()1(5)( −+=−− nxnxnyny . (10)

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11295 3

13. (a) (i) Explain the following properties of DFT.

(1) Convolution.

(2) Time shifting

(3) Conjugate Symmetry. (10)

(ii) Compute the 4 point DFT of }3,2,1,0{)( =nx . (6)

Or

(b) (i) Explain the Radix 2 DIFFFT algorithm for 8 point DFT. (8)

(ii) Obtain the 8 point DFT using DITFFT algorithm for

↑

= }1,1,1,1,1,1,1,1{)(nx . (8)

14. (a) (i) Realize the following using cascade and parallel form .

21

21

2.01.01

6.06.33)(

−−

−−

−+

++=

zz

zzzH . (12)

(ii) Explain how an analog filter maps into a digital filter in Impulse Invariant transformation. (4)

Or

(b) (i) Using Hanning window, design a filter with

ππ

ππ

≤≤=

≤≤−

= −−

||4

0

44)(

w

weeHd jzwjw

.

Assume 7=N . (12)

(ii) Write a note on need and choice on windows. (4)

15. (a) Explain in detail the architectural features of a DSP processor. (16)

Or

(b) Explain the addressing formats and functional modes of a DSP processor. (16)

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Reg. No. :

B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2010

Fifth Semester



(Regulation 2008)

Time : Three hours Maximum : 100 Marks

Answer ALL questions

PART A — (10 × 2 = 20 Marks)

1. What are even and odd signals?

2. Define aliasing effect.

3. Mention the relation between, Z transform and Fourier transform.

4. Give any two properties of linear convolution.

5. Calculate DFT of ( ) { }2,2,1,1 −−=nx .

6. Differentiate between DIF and DIT.

7. What are the advantages of FIR filter?

8. Mention the significance of Chebyshev’s approximation.

9. Define warping.

10. What is BSAR instruction? Give an example.

Question Paper Code : 53129 4

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53129 2

PART B — (5 × 16 = 80 Marks)

11. (a) (i) What do you mean by Nyquist rate? Give its significance. (6)

(ii) Explain the classification of discrete signal. (10)

Or

(b) (i) Explain in detail the Quantization of digital signals. (8)

(ii) Describe the different types of sampling methods used. (8)

12. (a) (i) Explain the properties of Z-transform. (8)

(ii) Find the impulse response given by difference equation.

( ) ( ) ( ) ( ) ( )122413 −+=−−−− nxnxnynyny (8)

Or

(b) (i) Test the stability of given systems. (8)

(1) ( ) ( )( )nxny cos=

(2) ( ) ( )2−−= nxny

(3) ( ) ( )nxnny =

(ii) Find the convolution. (8)

( ) { }2,2,1,1 −−=↑

nx , ( ) { }75.0,2,1,1,5.0 −=↑

nh

13. (a) An 8-point sequence is given by ( ) { },1,1,1,1,2,2,2,2=nx . Compute

8-point DFT of ( )nx by radix DIT--FFT method also sketch the

magnitude and phase. (16)

Or

(b) Determine the response of LTI system when the input sequence is

( ) { }1,1,2,1,1 −−=nx using radix 2 DIF FFT. The impulse response is

( ) { }1,1,1,1 −−=nh . (16)

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53129 3

14. (a) Design a low pass filter using rectangular window by taking I samples of

( )nω with cut off sequence of 1.2 radians/sec also draw the filter. (16)

Or

(b) The specification of defined low pass filter is :

( )

( ) πωπω

πωω

≤≤≤

≤≤≤≤

32.0;2.0

2.00;0.18.0

H

H

Design Chebyshev’s digital filter using bilinear transformation. (16)

15. (a) (i) With a neat diagram explain Von-Neumann architecture. (8)

(ii) What is MAC unit? Explain its functions. (8)

Or

(b) Explain the architecture of TMS320C50 with a neat diagram. (16)

–––––––––––––

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Reg. No. :

B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2011.

Fifth Semester



(Regulation 2008)

Time : Three hours Maximum : 100 marks

Answer ALL questions.

PART A — (10 × 2 = 20 marks)

1. What is a linear time invariant system?

2. State sampling theorem.

3. What is meant by ROC in z-transforms?

4. Write the commutative and distributive properties of convolution.

5. Draw the basic butterfly diagram for Radix 2 DITFFT.

6. Write the DTFT for (a) )()( nuanx n= (b) )1(3)(4)( −== nnnx δδ .

7. What is meant by linear phase response of a filter?

8. Compare bilinear transformation and Impulse invariant method of IIR

filter design.

9. Give the special features of DSP processors.

10. What is pipelining?

Question Paper Code : 66288

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66288 2

PART B — (5 × 16 = 80 marks)

11. (a) (i) Discuss whether the following are energy or power signals

(1) )(2

3)( nunx

n

=

(2) njw

Aenx 0)( = . (10)

(ii) Explain the concept of quantization. (6)

Or

(b) Check whether following are linear, time invariant, causal and stable.

(i) )1()()( ++= nnxnxny . (8)

(ii) )(cos)( nxny = . (8)

12. (a) (i) Obtain the linear convolution of

}2,1,2,3{)( =nx ↑

= }2,1,2,1{)(nh . (6)

(ii) A discrete time system is described by the following equation :

)1(2

1)()1(

4

1)( −+=−+ nxnxnyny

Determine its impulse response. (10)

Or

(b) (i) Obtain the discrete Fourier series coefficients of nwnx 0cos)( = .(4)

(ii) Determine )(nx for the given )2(x with ROC

(1) 2|| >z

(2) 2|| <z

21

1

231

31)(

−−

−

++

+=

zz

zzX . (12)

13. (a) (i) Explain 8 pt DIFFFT algorithm with signal flow diagram. (10)

(ii) Compute the DFT of }0,0,1,1{)( =nx . (6)

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66288 3

(b) (i) Describe the following properties of DFT.

(1) Time reversal

(2) Circular convolution. (10)

(ii) Obtain the circular convolution of

}1,2,2,1{)](1 =nx }1,3,2,1{)(2 =nx . (6)

14. (a) Design a butterworth filter using the Impulse invariance method for

the following specifications.

ππ

π

≤≤≤

≤≤≤≤

weH

WeH

jw

jw

6.02.0)(

2.001)(8.0

Or

(b) Design a filter with desired frequency response

ππ

ππ

≤≤=

≤≤−

= −

||4

3for0

4

3

4

3for)( 3

w

weeHd wjjw

Use Hanning window for 7=N .

15. (a) Explain the addressing modes of a DSP processor.

Or

(b) Describe the Architectural details of a DSP processor.

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421 4

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