| 摘要 |
PURPOSE: A coherent receiver in a CDMA(Code Division Multiple Access) cellular system is provided to maintain call quality uniformly by varying an integration period according to a change of channels. CONSTITUTION: Channel parameter extractors(301,302) extract their respective amplitude and phases from the base band signals(RxI,RxQ) outputted from a pilot sequence de-spreader(15). Adders(303,304) add the values extracted from channel estimators(309,310) each other. Size extractors(305,306) extract size by taking the absolute values for the difference between the extraction values obtained from the adders(303,304) and actual values. An adder(307) adds and outputs the values of an in-phase component(I) and a quadrature component(Q) outputted from the size extractors(305,306). A parameter comparator(308) adjusts an integration period according to the difference between the output of the adder(307) and a preset error reference value in order to compensate the channel estimator(309) with the modified period.
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