Design of Receiving Processor on Radio Signal and Multi-Rate
|School||Harbin Engineering University|
|Course||Communication and Information System|
|Keywords||Bandpass Sampling Theorem Multi-Rate Signal Processing CIC Decimation Filter Multi-Stage Decimation|
With the development of the techniques of the modern electronic and digital signal processing, software radio is becoming one of the hottest issues in wireless communication research, and it obtains achievements apparently in recent decades, which attracts a good many domains. There are many crucial technologies involved in it, including digital signal processing, digital up conversion, digital down conversion and so on. But by the limitation of current level of the analog to digital conversion device, wide band intermediate frequency digital sampling structure is the popular choice in software radio. So digital intermediate frequency technology becomes one of the most critical technology now.The main aim of this paper is according to the principle of the software radio, to finish some performance researches and improvement for the digital signal receiving processor.First of all, the paper’s background, purpose and meaning were explained, and the multi-rate signal processing was introduced briefly. And the basic theories of the software radio were introduced elaborately, including signal sampling theorem, decimation theory, multi-stage structure and polyphase structure for achieving efficient decimation and digital signal orthogonal transformation and so on.And then the structure of the digital signal receiving processor were analyzed, the cascaded integrator com(CIC) decimation filter was the most important part of it, so it also was the keystone of the paper’s research. With disscussion of the CIC filter, for its shortage, a compensation filter which is based on the sine function and a improved CIC filter which is based on the sharpening technique were proposed in this paper, both of compensation filter and sharpening technique can be used for improving the characteristics of passband and stopband of the CIC filter, by comparing the comprehensive performance, the filter which was disigned has some advantages over the conventional CIC filter and its improved one.At last, according to the TD-SCDMA communication system standard, the total improved scheme were simulated by MATLAB. With the parameters got from MATLAB simulation, the function modules of digital signal receiving processor structure were designed and described by Verilog HDL, the result of simulation proved the feasibility and established foundation of design for further actual application.