Monday, 13 March 2017

Experiment two: Discrete Fourier Transform

Discrete Fourier Transform (DFT) is used to convert digital signal in time domain into a signal in the frequency domain.

It is used to calculate a signal's frequency spectrum.
In this experiment,we calculated DFT of 4 and 8 point sequences.The 8-point sequence was a zero padded 4-point sequence.

Learnings from experiment:

  1.  Inverse DFT converges.
  2.  DFT produces periodic results with period N.
  3.  DFT coefficients are defined in the frequency range [0,2π].
  4.  As N increases, frequency spacing reduces, approximation error decreases, resolution of spectrum increases.
  5. As signal is expanded in time domain, spectrum is compressed in frequency domain.







9 comments:

  1. DFT is used for frequency domain analysis.

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    Replies
    1. DFT can calculate a signal's frequency spectrum. This is a direct examination of information encoded in the frequency, phase, and amplitude of the component sinusoids. For example, human speech and hearing use signals with this type of encoding.

      Delete
  2. Yes, the frequency is in the range of (0,2pie)

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  3. DFT requires N^2 complex multiplications.

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  4. Systematic and informative

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  5. This is a computationally inefficient method

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  6. This comment has been removed by the author.

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  7. DFT is frequency sampling of DTFT

    ReplyDelete

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