Patent ID: 6647077
Filing Date: 2003-11-11
Classification: H04B

Abstract:
An apparatus for characterizing a secondary path signal relative to a main path signal received in a multipath radio signal, said apparatus comprising:main and secondary magnitude inputs adapted to receive main and secondary magnitude values from the main and secondary path signals; a magnitude comparator adapted to receive the main and secondary magnitude values and to determine a magnitude of the secondary path signal relative to the main path signal; main and secondary phase inputs adapted to receive main and secondary symbol values from the main and secondary path signals; first main and secondary delay elements adapted to receive the main and secondary symbol values and to output delayed main and secondary symbol values; main and secondary differential decoders adapted to receive the main and secondary symbol values and the delayed main and secondary values and to output differentially decoded main and secondary symbol values; second main and secondary delay elements adapted to receive the differentially decoded main and secondary symbol values and to output delayed differentially decoded main and secondary symbol values; a correlator adapted to receive the differentially decoded main and secondary symbol values and the delayed differentially decoded main and secondary symbol values, and to determine a time offset of the secondary path signal relative to the main path signal based on identifying a symbol correspondence between the differentially decoded main and secondary symbol values; and a phase comparator adapted to received the main and secondary symbol values and the delayed main and secondary symbol values and to determine a phase difference between corresponding main and secondary symbol values based, in part, on said symbol correspondence.