[R] Fourier Transform with irregularly spaced x

From: Claudia Beleites <cbeleites_at_units.it>
Date: Mon, 03 Nov 2008 10:23:20 +0100


Dear all,

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,

Claudia  

-- 
Claudia Beleites
Dipartimento dei Materiali e delle Risorse Naturali
UniversitÓ degli Studi di Trieste
Via Alfonso Valerio 6/a
I-34127 Trieste

phone: +39 (0 40) 5 58-34 47
email: cbeleites_at_units.it

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Received on Mon 03 Nov 2008 - 09:25:34 GMT

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