The Implement And Optimize Of GMSK Modulate And Demodulate Through DSP In Software Defined Ratio

Software radio has started a new technological revolution in radio communication after the transition from analogue communication to digital communication. It had vast use in both of military and civil area. Software radio was a novel wireless communications technology, which was based on a general versatile programmable platform, it can realize the most communication functions and well satisfy the need of many new molds and functions just through software modules. With this method, the modification and upgrade of some system will become more convenient, and different systems could communicate with each other more effectively.After thoroughly studied some domestic and overseas papers in the aspect of software radio modulation and demodulation, this article toke GMSK as the research object. GMSK modulation patterns were usually used in the modern mobile communications.Minimum Gaussian frequency shift keying(GMSK) was a typical continuous phase modulation method with some excellent performance in constant envelope, compact spectrum, and anti-jamming performance.. GMSK can effectively reduce inter-channel interference, improve the efficiency of non-linear power amplifier ,and it had been widely used in mobile communications system( such as GSM system) and some other systems. Produced the detailed modulation and demodulation realization method. In the second part, the article analyzed the detailed modulation and demodulation realization method, utilizing the function formidable digital signal processing TMS320C6416 DSP to realize GMSK modulation and demodulation. In this part, it also shared the detailed procedure compiled in CCS2.2. Finally, a comprehensive analysis had been done to the arithmetic optimization of GMSK modulation and demodulation. With the unique linear assembly language of the C6000 series processors, it had realized the arithmetic of modulation and demodulation optimized by code, which meets the demand of the real time need of the multi-frequency receivers The execution plan of the paper was:(1) Have studied the implementation method of Digital modulation and demodulation in the software radio.(2) The demodulation and modulation technologies in digitalization method was studied. To fit for the need of burst communication systems, 1-bit and 2-bit differential demodulation method studied. A 1-bit demodulator was designed and released.(3) Using the combine platform of MATLAB and CCS IDE, produced the GMSK modulation and demodulation in the SEED-DEC6416 starter kit with C language, and gave the DSP data picture of GMSK modulation and demodulation in theCCS2.2.Generally analyzed the optimization of the GMSK modulation and demodulation process , gave the five step optimized method of C6416 concretely application situation and the important innovation which used the assembly language and linear assembly language realized the part of most operated arithmetic of the thesis.The study of the thesis was carried out by the method of theoretical analysis, scheme comparisons, simulations and DSP verifications. Results shew that the scheme designed was feasible and can be adopted in practice system after further optimization...