The Research And Realization Of Medium Wave Receiver Based On Software Defined Radio

Software Defined Radio is currently one of the hottest subjects for the military and mobile communication fields. Its basic conception is that making hardware as basic platforms, putting wideband A/D and D/A converters near antennas as much as possible, and using software realizes wireless and personal communication functions as much as possible. Such kind of radio systems have advantages of strong-general-purpose and good-portability capabilities, and are capable of changing modulation formats and carriers conveniently by modifying software. Software Radio is said to be the third innovation after analog-to-digital and fixed-to-mobile ones.In this dissertation, key theories and technologies of Software Defined Radio are studied deeply firstly, including the theory of signal sampling theory, multi-velocity signal processing, poly-phase filters structures, technology of digital filter and quadrature transformations. And deeply study the theories of digital modulation and demodulation technology for AM and FM signal.This dissertation has a deep research for medium wave receivers based the above basic theories and ideas, and brings forward a brand-new design scheme of medium wave digital receivers. Relative algorithms of medium wave digital receivers also analyzed and discussed in details in this dissertation. Designed AM,FM signal demodulation module which based on CORDIC algorithms and Numerical Control Oscillator based on Look-Up Table technology, All of these modules have good performance in my practice project.And then the hardware receivers realize medium wave intermediate-frequency-signal sampling,software demodulation and real-time broadcast. Compared with traditional medium wave analog receivers, medium wave digital receivers based on Software Defined Radio have simple hardware, flexible and strong functions. What's more, they can demodulate many kinds of modulated signals and are easy to upgrade and maintain which suit the development trend of current wireless communication.