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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,

  2. jcsd
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