Hi all, I am putting here my question since i think it has relation with the harmonic analysis. I am using matlab to solve a difference equation and i am getting a pretty random oscillation in the result. The data FFT shows that i have a very wide spectrum of harmonics with not very much distinctive peaks. My problem is how can i decide what kind of behavior i have here. The possibilities i have thought for my signal is to be white noise, chaotic behavior or that has a normal distribution(it looks like that but....) Since there is not expression of the equation, and i have only its data how can we tell what kind of behavior we are dealing with?! I know that it is a huge chapter with many things to discuss but since i have only the above resources what can i do? Thank you very much!