Msk Digital Modulation And Demodulation Technology

Without the constraint of hardware structure, software radio is regarded as a newrevolution to the structure of traditional radio communication system, due to itsvaluable commercial and military applications. However, to achieve compatibility,scalability, and adaptability, three technical challenges must be solved: Firstly, toconstruct an openly, standardized and extendable hardware/software architecture.Secondly, produce very powerful analog-digital converter and digital signal processors.Thirdly, to investigate multi-band, multi-rate, and multi-mode signal processingtheories or techniques. As such, to develop a high performance software radio, thisthesis concentrates on the various key technologies such as high rate ADC, digitalmodulation/demodulation and real-time processing. In this thesis, the digital MSKmodulation/demodulation is investigated, and a FPGA based software radio processingplatform is implemented, which can achieve successful digitalmodulation/demodulation. Theoretic analysis and experimental results show that thedeveloped system has excellent performance, which confirm the techniques describedin this thesis.In this thesis, the main contents are as follows. (1) The potentials and challengesof software radio are detailed. (2) The application of MSK to software is analyzed, andthe digital MSK modulation/demodulation is detailed. (3) ADDS based IF digitalMSK modulator is developed. (4) With the combination of digital orthogonaldemodulation and base-band difference phase techniques, real-time demodulation isachieved. (5) A FPGA based high-speed processor is developed. (6) An AD9244 basedADC processor is designed. (5) Some simulation examples are performed andexperimental results are provided.The main contributions of this thesis can be summarized as follows. (1) Variouskey technologies and challenges, including modulation/demodulation, IF ADC andreal-time signal processing, are investigated. More importantly, most of this work hasbeen demonstrated with our self-built platform, which can provide a technical guidancefor developing actual software radio system. (2) This techniques and concepts discussed in this thesis can be regarded as the PhaseⅡwork towards high performancesoftware radio. A practicable scheme for software radio using DDS, FPGA and IF ADC,is formed.