The Design Of High Speed DS-SS Receiver Based On SDR

Far distance, as large communication capability, high transmission quality and good secrecy are required in modern communication system, the spread spectrum communication technology has a bright application outlook in the future. With the development of Super Large Scale Integration (SLSI) and Electronic Design Automation (EDA) technology, in more and more occasions, people use Software Definition Radio (SDR) to implement the spread spectrum communication.The task of this thesis is to design a high speed Direct Seqcuence Spread Spectrum receiver based on SDR. As the receiver processes the intermediate frequency sampling signal directly and gives out base band information signals after interior process. As base on Software Definition Radio, this receiver has good flexibility, general utilization and transplant performance.This thesis gives the principle of spread spectrum communitiaon at first, emphasizes on introducing Direct Seqcuence Spread Spectrum (DSSS) and analyzes the general model based on the DSSS whick is used widest. Base on the model, this thesis discusses how to capture and keep in phase with the spread spectrum seqcuence. Modulation and demodulation, which is also one of the most important techniques in spread spectrum communication. This thesis discusses the principle of Differential Quadrature Phase Shift Keying (DQPSK) chiefly, and also gives out the method of modulation and demodulation and the carrier recovery scheme in DQPSK.In addition, this thesis builds the plantform of hardware and inplements the scheme of software. It gives the total system scheme as well as the implement details. The results of infield testing show that the receiver attains the expected performance.