  It is shown here that precision is gained by analyzing the interferometric
spectra directly from the interferograms, with no previous Fourier
transformation to put them in the standard frequency domain. The method is
based on the theoretical calculation of the lineshape, which gives a general
closed--form expression for the spectrum in the time domain and is directly
assimilable to the experimental interferogram. Error sources in Fourier
integrals, apodization, peak fitting with standard interpolation functions,
choice of background level, Stokes energy shifts, etc., are neatly avoided.
