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fft , power, rms , spectrum

Discussion in 'Mathematics and Physics' started by aswin p ajayan, Feb 5, 2014.

  1. aswin p ajayan

    aswin p ajayan Member

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    hi
    i am an electronics student. i trying to do a project on power spectrum analysis . i think if i could sample the ac mains using inbuilt adc of pic18f4550
    and perform a fourier transform,it might work . But the problem is that i cant understand fft algorithm .can anyone suggest some pdf's for my needs.


    also what should be the acquisition rate


    i am just a beginner . any threads might be helpful
     
  2. alec_t

    alec_t Well-Known Member Most Helpful Member

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  3. misterT

    misterT Well-Known Member Most Helpful Member

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    Fast Fourier Transform algorithms are not easy to understand because they are highly optimized.. they are not "intuitive". You need to work through all the theory from the beginning and then study computer science etc. to fully get into it.
     
  4. dave

    Dave New Member

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  5. misterT

    misterT Well-Known Member Most Helpful Member

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    The famous "Nyquist rate" states that you should sample at least twice the highest frequency to prevent aliasing. In practice you need to sample about 10 times the highest frequency if you want to have some chance to reproduce (or analyze) the signal.
     
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  6. MrAl

    MrAl Well-Known Member Most Helpful Member

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    Hi,

    I ran across this site:
    http://www.relisoft.com/Science/Physics/fft.html

    That attempts to explain the butterfly algorithm which breaks down the problem into smaller problems and so speeds up the computation.
    I did not read the whole reference so i cant say how accurate or complete it is, but it looked decent at first glance.
    There are bound to be tons of other references too just look for the butterfly algorithm(s).
     
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