Patent ID: 6704347
Filing Date: 2004-03-09
Classification: H04B

Abstract:
A searcher for use in a CDMA receiver to search optimum reception timing from reception data signals which are received through a plurality of paths, comprising:calculation means for calculating, in a time division fashion, correlation values between the reception data signals and successively delayed spreading codes, to produce summed up correlation values, wherein the calculation means comprises: despreading means for despreading the reception data signals by using the successively delayed spreading codes to produce the correlation values; decision means for determining the optimum reception timing from the summed up correlation values; summing means for summing up each of the correlation values in the time division fashion to obtain the summed up correlation values in the time division fashion, and further wherein the despreading means comprises: a spread code generator for generating a spreading code; a delay circuit for successively delaying the spreading code to produce the successively delayed spreading codes; a plurality of correlators for carrying out correlation calculations between the reception signals and the successively delayed spread codes to produce correlation values; the summing means comprising a plurality of adders for successively summing up the correlation signals to produce summed up correlation signals; a timing decision circuit for judging the reception timing from the summed up correlation signals to decide the optimum reception timing; and a plurality of switches between the correlators and the adders and between the adders and the timing judgement circuit, for selectively supplying the correlation values from selected ones of the correlators to the adders in the time division fashion and for supplying the summed up correlation values to the timing judgment circuit in the time division fashion.