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presentation on digital signal processing

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presentation on digital signal processing

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presentation on digital signal processing

  1. 1.  INTRODUCTION  TERMS AND COMPONENTS  WORKING OF DIGITAL SIGNAL PROCESSOR  COMPARISIONWITH MICROPROCESSORS  DIGITAL FILTERAND ITSTYPES  APPLICATIONS
  2. 2.  DIGITAL: Operating by the use of discrete signals to represent data in the form of numbers.  SIGNAL: A variable parameter by which information is conveyed through an electronic circuit.  PROCESSING: To perform operations on data according to the programmed instructions.  Digital signal processing :IT can be defined as analysis, interpretation, and manipulation of signals like sound, images time-varying measurement values and sensor data
  3. 3.  Converting a continuously changing waveform (analog) into a series of discrete levels (digital)
  4. 4.  The analog waveform is sliced into equal segments and the waveform amplitude is measured in the middle of each segment  The collection of measurements make up the digital representation of the waveform
  5. 5. 0 0.22 0.44 0.64 0.82 0.98 1.11 1.2 1.24 1.27 1.24 1.2 1.11 0.98 0.82 0.64 0.44 0.22 0 -0.22 -0.44 -0.64 -0.82 -0.98 -1.11 -1.2 -1.26 -1.28 -1.26 -1.2 -1.11 -0.98 -0.82 -0.64 -0.44 -0.22 0 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37
  6. 6.  A waveform is sliced up and converted it into digital form  Draw a simple waveform on graph paper  Scale appropriately  “Gather” digital data points to represent the waveform
  7. 7.  Compare the original with the recreating, note similarities and differences
  8. 8. Raw -150 -100 -50 0 50 100 150 0 10 20 30 40 Time Amplitude Ave before/after -150 -100 -50 0 50 100 150 0 10 20 30 40 Time Amplitude
  9. 9. Three most commonly used digital modulation schemes for transmitting Digital data over bandpass channels are: Amplitude shift keying (ASK) Phase shift keying (PSK) Frequency shift keying (FSK) When digital data is transmitted over an all digital network a scheme known As pulse code modulation (PCM) is used.
  10. 10.  A microprocessor with its limited speed is meant for low speed applications whereas the DSP is meant for fast real time applications.  Generally microprocessors useVan-nuemann architecture whereas most of the DSP processors use a modified Harvard architecture with two or three memory buses.
  11. 11. Texas DSP Processors 16-bit Fixed point arithmetic processors  TMS320C1X  TMS320C2X  TMS320C5X  TMS320C8X 32-bit floating point arithmetic processors  TMS320C3X  TMS320C4X
  12. 12. Digital filter:numerical procedure or algorithm that transforms a given sequence of numbers into second set of sequence that has some more desirable properties. DIGITAL FILTER INPUT SEQUENCE Output sequence
  13. 13. Broadly speaking ,two types of digital filters exists.  FIR Filters(Finite impulse response filters)  IIR Filters (Infinite Impulse response filters)
  14. 14. FIR filter: uses only current and past input digital samples to obtain a current output sample value. It does not utilize past output samples. Simple FIR equation is mention below. y(n)= h(0)x(n) + h(1)x(n-1) + h(2)x(n-2) + h(3)x(n-3) + h(4)x(n-4) IIR filter: uses current input sample value, past input and output samples to obtain current output sample value. Simple IIR equation is mention below. y(n)= b(0)x(n) + b(1)x(n-1) + b(2)x(n-2) + b(3)x(n-3) + a(1)y(n-1) + a(2)y(n-2) + a(3)y(n-3)
  15. 15. An ideal filter is transmits signal under the pass band without attenuation and completely suppress the signal in stop band. Characteristics –  it have constant gain in pass band and zero gain in the stop band.  It has linear phase response.  It must be causal .
  16. 16. Desired features depend on the application. INPUT SIGNAL OUTPUT SIGNAL Generated by sensing Having less noise Device(microphone) or interference Speech With reduced redundancy for better efficiency of transmission
  17. 17.  An analog filter is constructed using active, passive components like resistors, capacitors and op amps but a digital filter constitutes adder, multiplier and delay elements.  Digital filters are software programmable, which makes them easy to build and test.  Digital filters require only the arithmetic operations of addition, subtraction, and multiplication.  Digital filters do not drift with temperature or humidity .  Digital filters have a superior performance-to-cost ratio.
  18. 18. Digital signal processing has variety of applications in diverse fields like  Digital filtering  Spectral analysis  Speech processing  Image processing  Radar processing
  19. 19.  Robot control  Telecommunication  Consumer electronics  Biomedical engineering  Military applications
  20. 20. In graphic equalizers sound as well as frequency levels can varied to produce special sound effects and compensate for the lower sensitivity of the ear . • enhancement of edges in images improve recognition of object (by human or computer) edge – a sharp transition in the image brightness, sharp transitions in a signal (from Fourier theory) appear as high-frequency components which can be amplified

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