Design And Implementation Of Synchronization And Equalization System Based On DMB-TH Signal

The multi carrier mode of digital television terrestrial broadcasting transmission standard in our country(DMB-TH)using time domain synchronous orthogonal frequency division multiplexing(TDS-OFDM)modulation technology.TDS-OFDM has the advantage of high spectrum efficiency and low implementation complexity,,but are more demanding requirements for the synchronization performance of a receiving terminal,but because of multipath transmission,frequency selective fading will cause the sub carrier data's distortion of phase and amplitude,so the need for accurate channel estimation and equalization.Therefore,it is important to study the DMB-TH system's synchronization and equalization technology.This paper will present a design scheme of synchronization and equalization system model based on the DMB-TH signal,and FPGA implementation.This paper first introduces the DMB-TH transmission system,to study the transmission of the transmission system terminal,receiving terminal and the characteristics of the system frame structure,and focuses on the analysis of the problem of system synchronization and the fading characteristics of wireless channel.Then,this paper presents a kind of algorithm process scheme of DMB-TH synchronization and equalization system.The system mainly includes coarse synchronization,timing synchronization,frequency offset estimation,five aspects of micro channel estimation and equalization algorithm.Then research and analysis of various algorithms,and put forward the corresponding design.This paper presents a fine frequency offset estimation algorithm based on accumulation,and presents a fine frequency offset estimation scheme based on the combination of the algorithm with D-spaced algorithm.The scheme is compared with the fine frequency offset estimation scheme to reduce the amount of computation in half,cost low,easy to implement,estimated speed is faster,and the scheme through the accumulation value to deal with sudden frequency deviation.Then,this paper designs the operation mechanism of synchronization and equalization system.The system of planning for the three kinds of operation state:the time-frequency parameters capture,time frequency tracking,signal equalization.In the state of switching mechanism,through the correlation peaks decision,the output of the loop filter decision,the estimated value of the channel decision The estimated value of the channel decision to realize the state of switch.And designs of the operating echanism for three different conditions.By considering the output of each module and interface conversion,improve the ability to cope with various emergencies.Simulation results show that the system can achieve good synchronization and equalization and has high reliability.Finally,this paper presents the overall framework for the realization of FPGA synchronization and equalization system,and the various modules are realized.Among them,the system control module and the memory management module as the core,to control and manage the operation of the system.And through the module reuse,parallel processing and data cache conversion method,effectively improves the running speed of the system,reduces the consumption of resources.Then test the function of each module for the FPGA system,and the simulation results of FPGA and Matlab results are compared and analyzed,to verify the feasibility of the FPGA system implementation.