| 摘要 |
PURPOSE: A method for tracking PN(Pseudo Noise) code synchronizations in a CDMA(Code Division Multiple Access) mobile communication base station system is provided to synchronize PN codes between a terminal and a base station by using a DSP(Digital Signal Processor). CONSTITUTION: A DSP(10) transmits a search interval and an integral interval to an ATM(Asynchronous Transfer Mode)(20). The ATM(20) arithmetically operates energy values according to each chip, relating to the search interval. The energy values are stored in a memory(22) of the ATM(20). The DSP(10) reads all the stored energy values by an interrupt, and compares the read energy values with preset threshold values. If energy values are bigger than the preset threshold values, the DSP(10) decides whether the number of the energy values bigger than the threshold values is over the number of the threshold values. If so, the DSP(10) extracts at least more than four energy values. The DSP(10) outputs more than the four energy values to a demodulator(30). The demodulator(30) demodulates the energy values into original data, to search an optimum path and to complete an initial tracking process. If the initial tracking process is completed, the DSP(10) operates the second synchronous tracking mode.
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