The Digital Spread Spectrum Communication Of Power-line System -- Transmitting Part

The spread spectrum (SS) cornmunication system has stronger ability of resisting jamming, narrow band, and imjltipath interference than that of the conservation communication system. And because of its lower transmitting power spectrum, it also has the characteristics of low probability intercept and multiple access secure communication. The SS technology has been developing rapidly and has more and more comprehensive applications from the middle of the 50's to nowadays. It has shown strong vitality on the side of communication, data transmission and secure communication. This thesis primarily discussed and simulated the transmitting part of digital power line SS communication system based field programmable gate array (FPGA) ASIC chip. The power line communication, the SS communication system and the design technique of FPGA have been discussed in this thesis.The system mainly consisted of the PN code generator, the SS implement, the absolute-to-relative code converter, the digital sine wave signal generator, 2DPSK modulator and D/A converter.This thesis simulate the transmitting system of digital power line SS communication and achieve simulation respectively on the software -platform of MAX+PLUSH, the hardware test is also succeed.Chapter one introduce the aim and meaning of the task, the development related to PLC at present hi the world, the signal transmitting characteristic on power line, the summarize of SS communication technique, and the mainly content and design of the task.Chapter two introduces the background related to the theory. It mainly contains the digital modulate system, the SS communication theory and the direct sequence spread spectrum (DSSS) system.Chapter three introduces the VHDL- a sort of-hardware design describe language. It contains the characteristic, the basic structure, the function description.Chapter four mainly discuss the collectivity design, the implement and analysis of every function module, and achieve behavior simulation, arid give the result simulation.Chapter five draw a conclusion of the total design then make a proposal.