Monday, 13 March 2017

EXP 2: Discrete Fourier Transform



To perform this experiment, we used C programming and three cases. We used four arrays two for inputs (real and complex) other two for output. We passed these four arrays to the second function which was used to calculate DFT. Length of the output is same as that of the input signal. When the length of a signal increased the resolution of the output magnitude spectrum improved.When the length is increased by adding zeros after each value, the spectrum gets contracted and, the spectrum was seen to be periodic. Hence we could say DFT, a periodic signal.



11 comments:

  1. This comment has been removed by the author.

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  2. DFT always give periodic results and increasing the length by zero padding of the signal gives a better approximation of signal and resolution of spectrum increases.

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  3. When the signal is expanded in time domain it is compressed in the frequency domain.

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    Replies
    1. Yes, due inverse proportionality of time with frequency.

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  4. Total number of complex multiplication is given by N^2.

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  5. DFT produces periodic results

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    Replies
    1. Yes, twiddle factor makes it periodic.

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