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Analysis or results of FFT

  1. Nov 21, 2012 #1
    1. The problem statement, all variables and given/known data

    I would like get an advice whatever the plot of phase (in radians) of the FFT computation of audio file is correct.

    Is it not supposed to show a decrease as the frequency increases ?

    2. Relevant equations

    2m6kfhk.jpg
     
  2. jcsd
  3. Nov 21, 2012 #2

    mfb

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    Phase relative to what? And why does it go from -2500 to +8500 and not from -pi to pi?
    Where does the signal come from, why do you expect some specific phase?
     
  4. Nov 22, 2012 #3
    Phase relative to what?
    Relative to amplitude at specified frequencies

    And why does it go from -2500 to +8500 and not from -pi to pi?
    The command used unwrap() was supposed to make a range of -pi to +pi, however in MatLab it just doesn't work thus I assume it means -2500 rad to +8500 rad.

    Where does the signal come from, why do you expect some specific phase?
    The signal comes from the FFT of file audio.wav, I had no idea what I was expecting for "phase" the amplitude however makes clear sense.
     
  5. Nov 22, 2012 #4

    mfb

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    I don't think this makes sense.

    Well, where is the difference between a phase of x and x+2n*pi?

    Me neither, so why do you care about the phase?
     
  6. Nov 22, 2012 #5
    It was part of the question for analysis of an audio file. I end up submitting only amplitude component, the graph waveform however was correct, the range wasn't.
     
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