Research On Synchronization Technology Of Spread Spectrum System

With the communication technique development, extend spectral technique demonstrated his doughty strength of life. Especially in the day of electron opposition, it will become the most advanced communication system in the war. Compared with catapult, extend spectral receiver maybe has more difficulties in designing, because the received signal includes a lot of disturbed signal. As a result, it's very important to discuss this problem.This paper researches into synchronization techniques of direct-sequence spread spectrum systems, which include PN code acquisition, PN code tracking and carrier recovery. We studied several PN acquisition schemes such as single dwell serial acquisition scheme, large step acquisition scheme, matched filter technique, and presented structures, performance analysis, simulation models and partial simulation results for each scheme. Through thoroughly studying and contrasting we knew that the matched filter technique was the most suitable scheme for this project.In studying PN tracking technique, we concentrated on analyzing the performance of the delay-locked loop (DLL) and proposing its simulation model.The method of synchronous for carrier wave is researched in the four part. Both Square loop and Costas loop can complete it. Firstly, it's introduced the basic theory of both of them. Then aimed at Costas loop, we discussed briefly the PN code synchronization techniques for QPSK modulated spread spectrum systems.