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FFT implementation in FlexPro
- This topic has 2 replies and 2 voices and was last updated 21 years, 8 months ago ago by Richard Weisang.
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29.08.2003 at 01:52 #33417Richard WeisangKeymaster
How is FFT implemented in FlexPro? The FlexPro FFT results I get differ from that in another software.
29.08.2003 at 02:17 #33415Richard WeisangKeymasterHow is FFT implemented in FlexPro? The FlexPro FFT results I get differ from that in another software.
29.08.2003 at 02:17 #33416Bernhard KantzParticipantMany FFT implementations return the magnitude spectrum which is not normalized. Our FFT returns the complex amplitudes which is the magnitude spectrum multiplied with 1/N. You can decide where you do the normalization – on the FFT or on the inverse. We do it on the FFT because then the complex spectrum returned directly corresponds to the amplitudes an phases of the sinusoids used to reconstruct the time signal.
FFT
y_k = 1/N Sum([j=0 to N-1] x_j * Exp(-2*Pi*i*j*k/N)IFFT
x_j = Sum([k=0 to N-1] y_k * Exp(2*Pi*i*j*k/N)If you install the [b]Spectral Analysis Option[/b] for FlexPro then you have an exact-n FFT available, which returns the magnitude spectrum instead of the complex amplitudes.
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