ifft of signal without phase information I have a chemical spectrum with amplitude on the Y axis and wavenumbers on the X axis, sampling interval I think this is $1.5^{10}$ hertz. I would like to reconstruct the amplitude/time representation of the original signal by performing a ifft of the signal however I have no phase information. Since the information is unchanging (constant) over time I don't think that the phase information is necessary for reconstruction of the original signal. Can I set the phase information to zero and still reconstruct the signal in this case and how do I incorporate the sampling interval in the matlab ifft routine for accurate frequency calculation?

This is what I think I should be using

sig = abs(ifftshift(ifft(complex(data.YData))));


Thanks

Dave
This is tricky. The phase information impacts the time domain form very much. For example white noise and a delta impulse have exactly the same amplitude spectrum, the only difference is in the phase.

Without any further assumptions or extra knowledge this can't be done. For example if you know that the signal is stationary, you could just try a random phase. If it's the impulse response of a causal system, you could try a minimum phase.