Study and Implementation of Digital Direct Sequence Spread Spectrum Communication System
|Course||Communication and Information System|
|Keywords||Direct sequence spread spectrum communication Digital matched filter Carrier Synchronization FPGA|
The spread-spectrum technology with confidentiality and anti-jamming and anti-multipath , anti-fading and anti- noise ability , can address multiplexing and low power advantages , has used in many fields such as communication , positioning , ranging and control its unique advantages , the rapid development of universal concern in the international community . Direct Sequence Spread Spectrum (DSSS) communication has strong anti-jamming capability , communication distance and high reliability to become the most widely used as a spread-spectrum technology . With the rise of software-defined radio , spread spectrum systems gradually towards digitization and software development . Digital spread spectrum system has the advantages of low power consumption , small size , high system stability and reliability , versatility and flexibility . Therefore , the full digital spread spectrum communication system has become a development trend of today . Direct Sequence Spread Spectrum (DSSS) system theory and its capture performance , in-depth research , and FPGA implementation of a fully digital DSSS system . The main research content and work : ( 1 ) gives the block diagram of the the DS system transmitter and receiver simulation , and simulation waveforms . ( 2 ) focus on digital matched filter (DMF), adaptive gate circuit limit based on automatic decision threshold level control (ADTLC) limit technology and the improvement of the principle and performance of Costas (COSTAS) ring , etc. , in MATLAB / Simulink structures The simulation platform for simulation analysis . The ③ proposed DMF structure , an improved capture performance simulation analysis of the structure of the probability of detection and false alarm probability . ( 4 ) in the Quartus environment design and simulation to achieve the various modules of the DS system , including digital upconversion (DUC) , digital down -conversion ( DDC ) and digital COSTAS ring , digital matched filter ( DMF ) despreading unit key modules , and gives the simulation waveforms of the various modules . ( 5 ) complete hardware board design, fabrication and commissioning .