Phase regeneration of an M-PSK signal using partial regeneration of its M/2-PSK second phase harmonic

We propose and numerically investigate a phase regeneration technique that allows an M-PSK signal to be phase regenerated by an M/2-PSK (or even M/4-PSK) phase regenerator (applicable for M=2k, with k an integer). This scheme comprises three main parts; firstly, phase harmonic generation is used to create the second and third phase harmonics, secondly, the second phase harmonic (a down-converted M/2-PSK signal) is partially phase-regenerated, and thirdly and finally, the partially regenerated second phase harmonic and the third phase harmonic are mixed together to re-synthesize a phase regenerated replica of the original signal.