Research On Key Technologies And FPGA Realization Of Transmission System In Same Bandwidth

With the rapid development of communication technology,radio frequency bands with good performance and small interference are becoming increasingly scarce.They have become a scarce strategic resource.For this reason,new communication technologies and communication systems that can effectively improve the bandwidth efficiency are brought about,such as CDMA and so on.Efficient communication research has become a hot research field of communications.For the problem of increasingly scarce spectrum resources,this paper proposed LFM and voice SSB signal transmission system in same bandwidth,by theoretical analysis and software simulation,feasibility of the system was verified.Then,this paper analyzed the system performance under different channel.At last,the hardware implementation scheme of the system was given,programming and simulating each module of the system,the performance of the system was tested.The main contents of this paper are as follows:Firstly,the basic characteristics of LFM signal and the speech signal were analyzed,then introduced the basic principle of LFM and voice SSB modulation and demodulation,FrFT method of LFM signal demodulation was highlighted.Secondly,introduced implementation scheme of the LFM and voice SSB signal transmission system in same bandwidth in detail,the numerical method of FrFT was studied,by formulas derivation and software simulation,the feasibility of the system was analyzed.The performance of the system under white gaussian noise channel and Doppler frequency shift channel was tested and analyzed.Finally,hardware demonstration platform based on FPGA was built,hardware implementation scheme of the system was given,Verilog HDL program of each module based on hardware demonstration platform was finished and tested,the feasibility of the system was verified from view of the hardware implementation,and this paper provided a reference for engineering realization.