> I am confused by the function of ezfftf. The output is supposed to be
>the coefficients of the harmonics. For example, cf(0,i) and cf(1,i) are
>the coefficients of some sin and cos harmonic components. How to express
>the wave length or the frequency of that harmonics in terms of "i" and the
>interval and number of the periodic time series? Assume the time series
>data has interval of T, and the total number is n.
Based upon an off-line email between Jianjun and I
it was determined that the NCL function "fourier_info"
http://ngwww.ucar.edu/ngdoc/ng/ref/ncl/functions/finfo.html
was appropriate for his needs.
However, to further clarify the frequencies to which
the individual real [ cf(0,:) ] and imaginary [ cf(1,:) ]
coefficients refer, we will add the following to the
ezfftf documentation:
The frequency spacing is 1./N. The frequencies that
the 'cf' correspond to are:
cf(0,0) and cf(1,0) corresponds is 1./N
cf(0,1) and cf(1,1) 2./N
cf(0,2) and cf(1,2) 3./N
etc
---- Regards Dennis Shea_______________________________________________ ncl-talk mailing list ncl-talk@ucar.edu http://mailman.ucar.edu/mailman/listinfo/ncl-talk
This archive was generated by hypermail 2b29 : Wed Mar 12 2003 - 13:08:45 MST