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Abstract

A CDMA system capable of quickly establishing acquisition of a long code, a spreading code with a period considerably longer than a symbol length. The received phase of the long code is estimated by inserting an a priori code into a spread signal which is spread by the long code at a fixed interval, and by detecting the start timing of receiving the a priori code, where the a priori code has a correlation value of nearly zero with the long code, and an autocorrelation value of a triangular profile. Its transmitter has an a priori code inserting circuit, and its receiver has a replica generating circuit of the a priori code. In addition, the system includes a plurality of correlators for obtaining correlation values between the received signal and the replica of the a priori code, and a circuit for obtaining the maximum correlation values and their start timings of reception among these correlation values. It estimates the start timing of the a priori code from the start timings of reception that provides the maximum correlation values, and estimates the point separated by a fixed time from the estimated start timing to be the received phase of the long code.

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First Claim