Patent ID: 6392500
Filing Date: 2002-05-21
Classification: H03M,H04L

Abstract:
In a digital communication system, a data modulator comprising:phase map inputs for receiving at least four bits per unit baud interval, said at least four bits including convolutionally encoded bits and non-convolutionally encoded bits; phase map outputs for providing a set of coordinates of a two-dimensional phase space during each unit baud interval; and a phase mapping circuit coupled between said inputs and said outputs, said phase mapping circuit being configured to implement a phase point constellation having an origin and having phase points collinearly arranged along four diameters of said phase point constellation, wherein a first two of said four diameters intersect at substantially 90Â°, a second two of said four diameters intersect at substantially 90Â°, said first two diameters are rotated relative to said second two diameters at substantially 45Â°, said first two diameters have fewer phase points than said second two diameters, and for each of said phase points there exists, located at substantially the same magnitude and rotated approximately 90Â° from each phase point, another phase point having an equal data value for said convolutionally encoded bits.