The Research And Design Of Receiver System Based On Software Radio

The essential idea of the Software Radio is to take a general standardized and modularized hardware platform as a basis through software programming to implement a variety of radio functions, which greatly enhanced the flexibility of the system. As a major revolution in wireless communications history, Software Radio is a developing direction of radio technology in the future. This paper is to design a receiver system hardware platform based on the software radio.After introuducting the origin of software radio and general situation of development, we make a detail review about several architectures of software radio technology and research about key technology in software radio, and then briefly introduce several key indicators of receiver systems. Then, we propose the general plan of receiver system composed of a RF subsystem, a frequency synthesis subsystem and a integrated baseband subsystem. Detail analysis and comparison are made about each subsystem program.We choose the superheterodyne two down-conversion reception plan,and use ADS to simulate its gain distribution, frequency distribution.We takes the advantage of the PLL and DDS together, using the PLL and DDS mixing method to design frequency synthesizer. Integrated baseband subsystem uses the plan of FPGA+ARM and sampling chip AD9235. According to these plans, we describe the hardware circuit design of RF subsystem, frequency synthesis subsystem and integrated baseband subsystem, including LNA, down-conversion, power amplification,AGC; the generation of clock signal and local oscillation of frequency synthesis and so on; the design of A/D circuit and digital signal processing circuit and so on.Finally, we complete the test including LNA, power amplification, AGC,frequency synthesis subsystem and integrated baseband subsystem. And the test results are analyzed.