  A tomographic technique has been used in the past to decompose complex
signals in its components. The technique is based on spectral decomposition and
projection on the eigenvectors of a family of unitary operators. Here this
technique is also shown to be appropriate to obtain the instantaneous phase
derivative of the signal components. The method is illustrated on simulated
data and on data obtained from plasma reflectometry experiments in the Tore
Supra.
