Spectral analysis

Hi all,

I am dealing with paleoceanographic data and I have a C14 time serie
and one other variable. I would like to perform a spectral analysis
(fft or wavelet) and plot it. Unfortunately I don't know the exact
script to do this. Does anybody could send me an example to perform my
spectral analysis ?

I Thank you

David

There are a lot of possible ramifications to your query,
but for a basic spectral analysis of a series you can use
the function spectrum() in the "stats" package.

What is the role of the "other variable"?

Best wishes,
Ted.

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E-Mail: (Ted Harding) <ted.harding at nessie.mcc.ac.uk>
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Date: 06-Jun-07                                       Time: 22:34:07
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Hi all,

I am dealing with paleoceanographic data and I have a C14 time serie
and one other variable. I would like to perform a spectral analysis
(fft or wavelet) and plot it. Unfortunately I don't know the exact
script to do this. Does anybody could send me an example to perform my
spectral analysis ?

I Thank you

David

Invariably data of this nature are irregularly sampled in time, so you
should check whether the in-built spectrum() function is suitable for
your core data. I'm not aware of much else available in R, but one thing
I am aware of is a paper and R code by Mathias et al in the Journal of
Statistical Software:

http://www.jstatsoft.org/index.php?vol=11

It is issue 2 in that volume. This might be more suitable given your
data. The code is a few years old now and there isn't a ready built
package on CRAN so you'll have to compile it yourself.

HTH

G

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