Wednesday, 15 March 2017

Discrete Fourier Transform

DFT (Discrete Fourier Transform) is carried out to overcome the limitation of Fourier series as well as DTFT.
The programming language used in this experiment was C. For DFT(Discrete Fourier Transform) experiment we had considered 2 cases. The first case included calculations of 4 point DFT of given input signal. The second case had calculation of 8 point DFT of the same input signal x[n]. Magnitude spectrum was plotted for both the cases. The magnitude spectrum of 8 point signal has more resolution as compared to that of 4 point signal. We also performed the inverse Discrete Fourier transform of the same signal.

11 comments:

  1. Why does DFT gives discrete spectrum?

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    Replies
    1. DFT gives discrete spectrum because it assumes the input is periodic

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  2. DFT assumes input signal to be periodic and hence gives discrete spectrum

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    Replies
    1. Yes however DTFT produces continuous spectrum

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  3. DFT produces periodic results

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  4. The twiddle factors all lie on a unit circle; so the more the samples, the more that circle becomes complete, and hence the resolution gets better. The resolution increases because of more twiddle factors taken

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  5. DFT assumes input signal to be periodic and hence gives discrete spectrum

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    Replies
    1. Yes. DFT is basically frequency sampling of DTFT

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