Method and apparatus for digitally evaluating the phase of a modulated carrier

摘要

The method makes it possible digitally to evaluate the phase of any carrier that has been subjected to rPSK modulation subsequent to clock recovery, sampling, and digitizing the in-phase and quadrature components of the samples, by processing that is performed in polar coordinates and that comprises reducing the range over which the phase of each sample is defined to a range of + pi /r to - pi /r and then seeking the center of gravity over 2N successive samples (N being an integer) by performing successive averaging calculations, each time on two values, in application of an N-stage tree structure. Each average of two values is associated with an index indicative of the degree of reliability of the average, and those averages which are associated with a small reliability index are ignored while calculating subsequent averages in the tree structure.