[SciPy-user] the physical frequency of FFT

[Forrest Sheng Bao]

Hi,

I have some other questions about the fft function. Suppose I have N
sampling points and the sampling rate is Fs. I performed an N-point FFT,
using the code *fft(my_list_of_data)*.


   1. Doesn't the k-th point (0<k<N/2) correspond to the physical
   frequency (k*Fs)/(2*N)?
   2. Consider the single-sided case. If I just plot the FFT result by *
   plot(fft(my_list_of_data))*, the x-coordinate ([0,Pi]) is the image
   part and the amplitude is the real part, right?
   3. If I wanna estimate the power spectrum at each frequency, should I
   square the real part or computer the norm (square root of the sum of squares
   of the real and image part) of the complex number, at each FFT point?

Thanks,
Forrest

-- 
Forrest Sheng Bao
Ph.D. student, Dept. of Computer Science
M.Sc. student, Dept. of Electrical & Computer Engineering
Rm 115, Experimental Sciences Building
Texas Tech University, USA
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