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Cosine Fourier Transform Spectroscopy

  1. Apr 8, 2010 #1
    Hey all,

    I'm doing a cosine/sine inverse fourier transform of some interferometer data in IDL and I'm having some serious issues. I'm thinking that the cosine/sine is possibly overflowing...but I'm not sure. Here is my code:

    Code (Text):

    ;Inverse Fourier Transform  
     29 for i=0,15 do begin ;Channel
     30   for j=0,1 do begin ;Spectrograph
     31     for k=0,700 do begin ;Wavenumber
     32       int = reform(counts[i,j,*])
     33       x = 2 * !pi * v[k] * p
     34       BPc[i,j,k] = 4 * total(int * cos(x))
     35       BPs[i,j,k] = 4 * total(int * sin(x))
     36       BP[i,j,k] = sqrt(BPs[i,j,k]^2 + BPc[i,j,k]^2)
     37     endfor
     38   endfor
     39 endfor
     
    BPs, BPc, and BP are all float arrays of dimensions [16,2,701]
    Counts is the photon counts of the input spectrum. This is what I'm taking the IFT of.
    v[k] is the wavenumber
    p is the frame location of the interferometer
    I'm not extremely familiar with IDL, I'm having to use it for this job, but I have never used it before.

    I know this may be hard to debug without more background information, I'm hoping that there is some obvious mistake or someone here is an IDL guru. Thanks for any help,

    -Dylan
     
  2. jcsd
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