Michelson interferometer and Fourier transforms

Turning back to the Michelson interferometer and Fourier transform spectroscopy, let us first consider the interferogram of a continuous spectrum. Each spectral element of infinitesimal width rf and intensity I (v) gives rise to the same interferogram pattern as a narrow line [see Eq. (2.6)], and the actual interferogram is the superposition of all these... 

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