Patent ID: 7876811

Claim:
A spreading-code synchronization detection method for a spectrum spreading signal obtained by spectrum-spreading data having a bit transition period that is a multiple of one period of a spreading code with the spreading code, comprising: a unit-period correlation-calculation linear-addition step of performing a process for obtaining a linear-addition correlation-calculation result equal to a value obtained by linear additions of results of correlation calculations between the spectrum spreading signal and the spreading code, every unit period which is a multiple of one period of the spreading code and shorter than the bit transition period; an absolute-value calculation step of calculating the absolute value of the linear-addition correlation-calculation result obtained every unit period in the unit-period correlation-calculation linear-addition step; an absolute-value addition step of adding the absolute value of the linear-addition correlation-calculation result obtained every unit period, obtained in the absolute-value calculation step, for a plurality of unit periods; and a correlation-point detection step of detecting a correlation point from a value obtained by adding the absolute values in the absolute-value addition step; wherein the spectrum spreading signal to which the spreading-code synchronization detection is applied is stored in a memory for the plurality of unit periods for which additions are performed in the absolute-value addition step, and the spectrum spreading signal is read from the memory at a higher speed than a speed used in writing into the memory and the unit period correlation-calculation linear-addition step and the subsequent steps are performed to increase the speed of the process for detecting a correlation point faster, characterized by using a digital matched filter to perform the correlation calculations between the spectrum spreading signal and the spreading code.