Hilbert transform of a constant envelope signal using the time-warping technique

A method of performing the Hilbert transform of a constant envelope broadband signal is presented. The method is based on a time-warping technique which transforms the constant envelope signal into a harmonic one. The time-warping can be performed if the instantaneous phase (frequency) of the signal is known. Obtained in such a way the harmonic signal, given in the transformed time domain, has unit frequency. The Hilbert transform is performed in the transformed time domain, simply by delaying the harmonic signal by a quarter of its period.