FFTW Cycle Phase

[skiner36]

I am using FFTW to get the frequency and amplitude from an array of double values. IS it possible to use FFTW to also get the phase. If it is then could someone give me some example code of how to do it.

Many thanks,

John

[lastchance]

When you work out fourier coefficients of a periodic signal then you can sum over any length equal to the period and you would get the same coefficients; so, no, I can't see how you would identify phase(s).

If you have a monochromatic signal then subtract the average and use your position relative to the zero crossings - but then you wouldn't need an FFT anyway.

[Ganado]

Phase is just arctan(imaginary/real), right? Each complex sinusoid of the signal can have a different phase, though.