Patent ID: 6229840
Filing Date: 2001-05-08
Classification: H04B,Y02D

Abstract:
A diversity circuit for receiving a spread spectrum modulated wave signal, the diversity circuit comprising:a plurality of antennas;a plurality of delay circuits that are respectively configured to provide different delay times to a plurality of radio-frequency signals received by the plurality of the antennas;a combiner configured to add outputs of the plurality of the delay circuits and to provide a combined output;a receiver connected to demodulate the combined output and to provide a demodulated output; anda digital signal processor configured to process the demodulated output by using a Rake receiver wherein the Rake receiver provides a delayed de-spreading code to each of signals having the different delay times provided by the plurality of delay circuits and combines the results so as to provide a decoded output,wherein the Rake receiver includes:a plurality of delay elements each having a different delay amount corresponding to a respective delay time value provided thereto;a de-spreader code generator that outputs a de-spreading code;a search correlator that receives the de-spreading code output by the de-spreading code generator and that receives the demodulated output, the search correlator configured to shift a phase of the de-spreading code to calculate a correlation between each of the signals and the de-spreading code, the search correlator outputting the respective delay time values to the plurality of delay elements;a plurality of finger receivers that receive the demodulated output and that receive the de-spreading code respectively delayed by a corresponding one of the plurality of delay elements; anda combiner configured to combine outputs of the plurality of finger receivers into a single output signal,wherein first time values which correspond to time differences between the respective delay time values of the plurality of delay elements of the Rake receiver, are each less than second time values which correspond to time differences between the respective delay times of the plurality of delay circuits.