1D fft and spectra

Hi All,

I have a question regarding the 1D fft and 1D spectra, in respect to
the very different results for the spectra constructed using ezfftf
comparing to the spectra from specx_anal.
Attached is the plot with the resulting curves. On the left hand side
is specx_anal curve, and on the right hand side is the curve from
ezfftf.
In addition to very different shape of the curve and very different
values on the Y axis, I have also found a mismatch between the
variances calculated from the two spectra. From the description of
the specx_anal, area under the curve should give the total variance
of the initial v
ariable. I've tried comparing the variance with the area under the
curve from ezfftf and curve from specx_anal and I get about 5 times
larger value for the integral under specx_anal:
integral(spectra from ezfftf) = 0.291434
variance(data) = 0.292072
xvari = 0.291501
xvaro = 0.291501
integral(spectra from specx_anal) = 1.71725
xvari and xvaro are the attributes of the result of specx_anal.

In addition to the plot, I've also attached the code with both
routines and a file with sample of data I used for this example.

Does someone know what is the difference?

Thank you,
Verica

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http://www.atmos.ucla.edu/~verica/

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"The art of being wise is the art of knowing what to overlook."
                                                 William James

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