Research And Realization Of Some Key Technologies Of Software Radio

Software Defined Radio (SDR) technology is widely used on the wirelesscommunication field, and in recent years it is a hot research topic.This research is basedon two projects, one is the country’s twelfth five-year plan project about dangerousliquid’s detection, the other one is a national defense project about radar signal processing.In this research,we talked about the key technology about SDR, such as Digital DownConversion technology, baseband signal’s processing and radar clutter map processingtechnology.DDC (Digital Down Convert) technology is an important technology on SDR field.The analog signal we received from Radio Frequency module, has high frequency and isnot convenient for us to process when after A/D samping. DDC technology now is used todown converting the high frequency signal, and then reduce sample rate by decimatingand filtering, so we can process the data later. This research is focus on DDC optimization,it use NCO and multiplier to impliment the mixing module, and use CIC fiter to decimatethe sequence, deleting halfband fiter and FIR filter, then combine MATLAB and FPGA todesign the system. This design is implimented on ALTERA’s stratix II hardware platform,and the result shows that this optimization ideology can be achieved, and it not only thrifthardware resources, but also improve calculate speed.Baseband signal processing technology is related to algorithm and systemoptimization, it’s also a central issue on SDR field. Combined with a dangerous liquids’sdetecion project, this research talked the process of instantaneouts phase, and usedCORDIC algorithm to solve problem, then correct some error blind spot. Further, useMATLAB software to Simulink FPGA’s implement,then design this algorithm on FPGAbank, besides, we use sinaltap tool to achieve data and analysis data’s error. Experimentsexhibit that the system has good performance and meet the design requirements.Radar clutter map processing part is based on a national defense project, and deal withthe design and implement of the system. This research is focus on some important part such as the data buffering, iterate operation when number of sector is varied, selectmaximum or average data when sector isn’t updata, and backdata’s feedback problem.Then impliment the clutter map process on the xilinx’s virtex-II pro hardware plantform,The result shows that this design is correct and has good performance.