Abstract: A method and apparatus for estimating the phase differential of a transmitted electromagnetic signal from the amplitude envelope of the signal. The apparatus includes a sampler, phase estimator and demodulator. The phase estimator uses a Hilbert transform or an approximation of the Hilbert transform to estimate the phase differential. The method may be applied to time domain or frequency domain signals. The phase differential is estimated by taking the differential of a function of the envelope, and applying the Hilbert transform to this differential. The resulting phase differential, after correction for sign ambiguity may be used to demodulate the received signal.

Abstract: A method for allowing a number of wireless transceivers to exchange information (data, voice or video) with each other. A first frame of information is multiplexed over a number of wideband frequency bands at a first transceiver, and the information transmitted to a second transceiver. The information is received and processed at the second transceiver. The information is differentially encoded using phase shift keying. In addition, after a pre-selected time interval, the first transceiver may transmit again. During the preselected time interval, the second transceiver may exchange information with another transceiver in a time duplex fashion. The processing of the signal at the second transceiver may include estimating the phase differential of the transmitted signal and pre-distorting the transmitted signal.