The Design And Impliment Of A 4FSK Modulation And Demodulation Based On DCR System

In the professional field of radio communications, digital trunked radio system is the most important means of communications. In the past some time analog interphone occupied the main market in china. However, with the work environment of interphone changing and demands of interphone communication increasing, analog radio has been difficult to adapt to the private wireless communication environment in current. Therefore, domestic and foreign interphone products are actively converted analog to digital. Digital radio are not only able to complete basic communication function of analog radio while can achieve data transmission functions such as text messaging. It is easy to process digital signal by computer. So the functionality and quality and capabilities of digital radio are better than analog radio. Digital radio can meet the needs of private wireless communication environment in modern.This paper studies the latest digital radio standard of Digital Convenience Radio Equipment for Simple Service(DCR) that is formulated by Association of Radio Industries and businesses in Japan 2010, which uses 4FSK modulation and demodulation, FDMA technology, the symbol rate is 4.8kbps, data and voice communications can be carried out simultaneously. This paper studied several key technologies of 4FSK frequency modulation and demodulation and baseband signals processing based on the Japanese DCR standards. Achieve and simulate communication in software radio platform of DCR system at last.First this paper introduces the theoretical scheme of 4FSK modulation and demodulation system based on DCR standard. Elaborate the related the baseband signal processing theory and the basic principles of 4FSK modulation and demodulation. Secondly, propose the specific design DCR modulation and demodulation system. Design and simulate the basic theory of the baseband signal processing module, such as including the design and simulation of the square-root raised cosine FIR filter, inversed sinc(Isinc) filter, frame synchronized detector in Matlab. After 4FSK frequency modulation and demodulation scheme of DCR RF module are simulated, analysis of coherent and non-coherent demodulation algorithm BER curves in Matlab; The next, build the software radio platform of DCR system, explain the design of data acquisition module and the CSD quantization coding FIR filter, achieve the baseband modulation and demodulation system on this platform. Finally, introduce the DCR system hardware platform structure; Test the main modules of hardware platform, and give test results.