  Resampling by interpolation is the traditional method to process
interferograms from non-uniformly sampled Fourier transform spectrometers. The
non-uniform fast Fourier transform (NUFFT) is an alternative approach that has
been mostly overlooked. With the aid of experiments on a high-resolution
interferometer with a variety of optical sources, these two methods are
compared. It is found that the NUFFT is comparable to interpolation in spectral
profile shape and spectral noise levels and is better in spectral amplitude and
computer performance. A significant advantage is also found in the case of
under-sampling and noise performance by NUFFT due to the unique non-periodic
nature of non-uniform sampling. In addition, a novel implementation of NUFFT is
presented and analysed.
