Discrete Fourier Transform

Discrete Fourier transform (DFT) takes a finite number of samples of a signal and transforms them into a finite number of frequency samples of that signal. We have used C programming and analysed three cases. A finite 4 point sequence was taken as input. The length of the output signal was same as input signal. When the signal is zero padded to an 8 point sequence, we observe that the resolution of the output magnitude spectrum improved. Now the input sequence is expanded to an 8 point sequence by adding alternate zeros. This compresses the spectrum in frequency domain. Also, DFT produces periodic results.

Originally posted at: https://chaitanya33.wordpress.com/2017/03/13/discrete-fourier-transform/

Comments

  1. DFT has widespread applications in SpectralAnalysis of systems, LTI systems, Calculating convolution of signals,multiplication of large polynomials, noise removal et

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    1. Yes. Thank you for mentioning the applications

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  2. By appending more zeroes, the missing values in less point DFT are present in the DFT with more point.

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    1. Yes. Frequency spacing reduces and hence approximation error reduces

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  3. DFT is easier to implement and finds its application in FSM method

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  4. It is used for Fourier analysis of a signal

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  5. DFT is periodic in nature because of periodic nature of twiddle factor

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  6. The approximation error reduces by appending the input sequence by zeroes.

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  7. Results of DFT can be stored in memory

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  8. DFT uses sampling of frequency response.

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