Fft on data points

hi, im a new root user and need some help! :slight_smile: i have some data points (ascii) from an oscilattion and try to find the frequency. ive installed the fft packages. can you give me some advices how to do a fft with this plot? i only find some fft tutorials with an histo.
thanks a lot!
on the picture you can see the oscilattion and my little macro


but this tutorial works only for an histo, how can i do the fft with my tgraph, sry i dont get it :frowning:

[url]Complex number in Root histogram?