Code Division Multiple Access (CDMA) frequency planning with its simple, high-frequency spectrum utilization and a unique anti-fading, soft capacity, soft switching, Acer diversity and flexibility of variable-rate transmission, and other technical features, has become the third generation mobile communication System of mainstream technology. M sequence papers to the base-band signal DSSS modem to achieve CDMA spread spectrum modem modeling. Design and Implementation of papers, the company used altera MAX7000S series of Epm7064slc44-10 chip in Quartus Ⅱ 5.0 software programming and simulation, the last in Protel 99 SE software produced in the schematic and PCB board, through the observation of the actual oscilloscope DSSS Modem and the waveform Quartus Ⅱ 5.0 wave simulation software to compare and associated analysis. Design modules include a power supply, clock generation module, base-band signal generator module, modulation module, and demodulator modules. Demodulation in the course of a spring integral sliding catch to achieve receive relevant information and PN code (m sequence) synchronization.
Keyword: CDMA, direct sequence spread spectrum, m sequence code, related to spring integral sliding catch, Quartus Ⅱ 5.0, Protel 99 SE.
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