[R] inverse fourier transform

From: stephen sefick <ssefick_at_gmail.com>
Date: Sat, 01 Mar 2008 19:04:44 -0500


y<-ts(x, frequency=1/15)
spec.pgram(y, log="no")

There is high power in the very low frequency range for the data set of continuous dissolved oxygen on which I am preforming this analysis.  This is the seasonal trend due to temperature (and all things that are associated- photosynthesis, respiration, and anything else on which the doubling of a reaction rate ever ten degrees celcius would act). I would like to make this low frequency spike zero and then inverse fourier transform to get the "filtered" signal. spec.pgram spits out a matrix

z<-spec.pgram(y, log="no")
print(z)

spec, frequency, and phase are returned. They are not matched up and I would like to take out the frequency and its associated spectrum in the range of 0-6.53*10^6. Any suggestions? thanks

Stephen

-- 
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annoying little problems of being mammals.

								-K. Mullis

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Received on Sun 02 Mar 2008 - 00:07:17 GMT

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