Study On Demodulation Method Of Software Radio

In chapter 1 and chapter 2 of this paper, the basic theory and concept of software radio are discussed. In chapter 3, architecture of the system is determined according to the design requirement. In chapter 4, demodulation method of analog signal and digital signal are discussed. In the same chapter, theory of modulation recognition is narrated. Orthogonal transformation is selected as the only method for demodulating signal. In chapter 5, demodulation methods of AM, FM, 2ASK, 2FSK, 2PSK and 2DPSK are explained in detail. Demodulation models of these signals are established in Simulink. During this process, parameters that meet the requests of project are determined. In chapter 6, hardware design and software design of the system are introduced.All the contents in this paper are the summary of practice. This paper is illustrated with plenty of pictures. In chapter 5, demodulation models of many modulation systems are established. Square loop Model is established to detect carrier. In this paper, oscillogram and spectrum of every demodulation signal are presented. Also, in this paper, factors have impact on bit error rate in transmission process are analyzed.