1. UNIT-5 Filter Designing

2. INTRODUCTION The Digital filters are discrete time systems used mainly for filtering of arrays. The array or sequence are obtained by sampling the input analog signals. Digital Filters performs the frequency related operations such as Low-pass, High-pass, Band Reject,Band Pass and all pass etc. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 2

3. The Design specifications include cut-off frequency, sampling frequency of I/P signal, Pass band variation, stop band attenuation approximation, type of filter and realization form etc Digital filters can be realized through hardware or software. Actually speaking, the software digital filters need digital hardware for their operations 10/16/2015D.MOHAN Assoc.Professor ECM Dept 3 INTRODUCTION

4. Analog Low Pass Filters Model 10/16/2015D.MOHAN Assoc.Professor ECM Dept 4

5. Digital Low Pass Filters Model 10/16/2015D.MOHAN Assoc.Professor ECM Dept 5

6. Digital LPF Example 10/16/2015D.MOHAN Assoc.Professor ECM Dept 6

7. Comparison of Analog &Digital Filters 10/16/2015D.MOHAN Assoc.Professor ECM Dept 7

8. Types of Digital Filters Two types (1). Finite Impulse Response (FIR) (2). Infinite Impulse Response (IIR) 10/16/2015D.MOHAN Assoc.Professor ECM Dept 8

9. Finite Impulse Response (FIR)  Basically these are Linear Time Invariant(LTI)Systems So these are characterized by unit sample response.  The FIR systems has finite duration unit sample response. i.e. h(n)=0 for n =M  Unit sample response exist only for the duration for 0 to M-1.Hence this is FIR.  Out put of FIR depends only upon present and past inputs since it is non –recursive i.e. it does not use feedback 10/16/2015D.MOHAN Assoc.Professor ECM Dept 9

10.  These are also Linear Time Invariant(LTI)Systems So these are characterized by unit sample response.  The IIR systems has infinite duration unit sample response. i.e. h(n)=0 for n<0  Unit sample response exist only for the duration from 0 to ∞.Hence this is IIR  Out put of IIR depends only upon present input as well as past inputs and out puts. Since it is recursive i.e. it uses feedback 10/16/2015D.MOHAN Assoc.Professor ECM Dept 10 Infinite Impulse Response (IIR)

11. Design Techniques 10/16/2015D.MOHAN Assoc.Professor ECM Dept 11

12. Analog filter Design 10/16/2015 12 D.MOHAN Assoc.Professor ECM Dept

13. Analog Filter Design 10/16/2015 13 D.MOHAN Assoc.Professor ECM Dept

14. Analog Filter Design 10/16/2015 14 D.MOHAN Assoc.Professor ECM Dept

15. Analog Filter Design 10/16/2015 15 D.MOHAN Assoc.Professor ECM Dept

16. Analog Filter Design 10/16/2015 16 D.MOHAN Assoc.Professor ECM Dept

17. Analog Filter Design 10/16/2015 17 D.MOHAN Assoc.Professor ECM Dept

18. Analog Filter Design 10/16/2015 18 D.MOHAN Assoc.Professor ECM Dept

19. Analog Filter Design 10/16/2015 19 D.MOHAN Assoc.Professor ECM Dept

20. Butterworth Low-pass Filter 10/16/2015 20 D.MOHAN Assoc.Professor ECM Dept

21. Chebyshev Low-pass Filters 10/16/2015 21 D.MOHAN Assoc.Professor ECM Dept

22. Elliptic Low-pass Filter 10/16/2015 22 D.MOHAN Assoc.Professor ECM Dept

23. How do we design a Filter? 10/16/2015 23 D.MOHAN Assoc.Professor ECM Dept

24. Analog Filter Design 10/16/2015 24 D.MOHAN Assoc.Professor ECM Dept

25. Design of Butterworth Low-pass Filter 10/16/2015 25 D.MOHAN Assoc.Professor ECM Dept

26. 10/16/2015 26 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

27. 10/16/2015 27 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

28. 10/16/2015 28 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

29. 10/16/2015 29 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

30. 10/16/2015 30 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

31. 10/16/2015 31 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

32. 10/16/2015 32 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

33. 10/16/2015 33 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

34. 10/16/2015 34 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

35. 10/16/2015 35 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

36. 10/16/2015 36 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

37. 10/16/2015 37 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

38. 10/16/2015 38 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

39. 10/16/2015 39 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

40. 10/16/2015 40 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

41. 10/16/2015 41 D.MOHAN Assoc.Professor ECM Dept Design of Butterworth Low-pass Filter

42. 10/16/2015 42 D.MOHAN Assoc.Professor ECM Dept Butterworth Polynomials

43. Example -1 10/16/2015D.MOHAN Assoc.Professor ECM Dept 43

44. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 44 Solution for Example -1

45. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 45 Solution for Example -1

46. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 46 Solution for Example -1

47. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 47 Solution for Example -1

48. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 48 Solution for Example -1

49. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 49 Solution for Example -1

50. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 50 Example -2

51. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 51 Solution for Example -2

52. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 52 Solution for Example -2

53. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 53 Solution for Example -2

54. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 54 Transformation

55. Problem : 1 10/16/2015D.MOHAN Assoc.Professor ECM Dept 55

56. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 56 Transformation from LPF to HPF

57. Problem : 2 10/16/2015D.MOHAN Assoc.Professor ECM Dept 57

58. Problem : 3 10/16/2015D.MOHAN Assoc.Professor ECM Dept 58

59. Transformation 10/16/2015D.MOHAN Assoc.Professor ECM Dept 59

60. Transformation 10/16/2015D.MOHAN Assoc.Professor ECM Dept 60

61. Transformation 10/16/2015D.MOHAN Assoc.Professor ECM Dept 61

62. Transformation 10/16/2015D.MOHAN Assoc.Professor ECM Dept 62

63. Transformation 10/16/2015D.MOHAN Assoc.Professor ECM Dept 63

64. Summary Analog to Analog Transformation 10/16/2015D.MOHAN Assoc.Professor ECM Dept 64

65. Example 10/16/2015D.MOHAN Assoc.Professor ECM Dept 65

66. Solution 10/16/2015D.MOHAN Assoc.Professor ECM Dept 66

67. Solution 10/16/2015D.MOHAN Assoc.Professor ECM Dept 67

68. 10/16/2015D.MOHAN Assoc.Professor ECM Dept 68 Example