instantaneous phase from a power spectrum

I have manually generated a power spectrum for an AR(2) time varying process (which I have incidentially scaled by the variance of the process). I estimated this over the shannon spectrum of -0.5 to +0.5 which contains a grid of size N. Thus I have a matrix of size N*M where M is the number of data points observed.

I would like to be able to estimate the instantaneous phase / frequency of this process from my power spectrum.

Does matlab have any built ion tools to do this? If not what approach should I take? I see there is an "dspdata" class in the sig proc toolbox but I have never used it.

Many Thanks

Answer 1

[TideMan]

Phase from a power spectrum? AFAIK, phase is destroyed in the process of calculating the PSD.