So I have a power spectrum of a given function, which is supposed to be a superposition of four sinusoidal terms with frequencies that range from 1xomega to 4xomega. My spectrum looks something like this: http://upload.wikimedia.org/wikipedia/commons/4/4f/Triangle-td_and_fd.png What exactly does this spectrum tell me? I know it plots the length squared of a vector that has the real and imaginary components of the amplitude. Mine looks like the top one of the one I posted, its a triangle but mine only has two triangles and the rest are flat lines. I unfortunately don't have a book, and the prof only gave us notes on the fourier transform, so I am really stuck here. How do I interpret a flot of these triangles on the frequency-amplitude plot?