HARMFIT: Sinusoidal harmonic curve fitting

Computes harmonics of a phase signal

This is the core formula of discrete Fourier transform: it simply computes the amplitude and phase shift of fundamental or harmonics of a phase signal.
Example:
t = linspace(0,2*pi);
x = 2*cos(t + pi/2) - cos(3*t) + rand(size(t));
harmfit(t,x,1:4)

returns estimations of amplitudes/phases for the first four harmonics.