A set of phases defining an `address` and a `spreading key` is selected. These are employed in determining a preamble waveform and a traffic waveform. The preamble carrier waveform is a sum of a set of tones each offset by its phase, whereas the traffic carrier waveform is the product of these same offset...http://www.google.fr/patents/US5519692?utm_source=gb-gplus-shareBrevet US5519692 - Geometric harmonic modulation (GHM)-digital implementation
