[R] Fourier Transform with irregularly spaced x
cbeleites at units.it
Mon Nov 3 10:23:20 CET 2008
I work with (vibrational) spectra: some kind of intensity (I) over frequency
(nu), wavelength or the like.
I want to do fourier transform for interpolation, smoothing, etc.
My problem is that the spectra are often irregularly spaced in nu: the
difference between 2 neighbouring nu varies across the spectrum, and data
points may be missing.
Searching for discrete fourier transform I found lots of information and
functions - but I didn't see anything that just works with irregularly spaced
signals: all functions I found take only the signal, not its x-axis.
Where should I look?
Or am I lacking some math that tells how to do without the frequency axis?
Thanks a lot for your help,
Dipartimento dei Materiali e delle Risorse Naturali
Università degli Studi di Trieste
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email: cbeleites at units.it
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