Design Of Carrier Synchronization And Bit Synchronization System Based On FPGA

In order to meet the needs of various kinds of multimedia information in communi-ication system,the carrier frequency of the transmission signal is getting higher and hig?her.While updating the mobile communication system,the synchronization perf-ormance of the communication system is more strictly.Fast and accurate carrier and bit s-ynchronization technology become hotspots in the field of communication system while frequency hopping technology which improve the anti-interference ability of the systemis is widely used in military and civil communication.Research and master the carrier synchronization and bit synchronization based on digital phase locked loop has practical significance.The most efective way to realise phase tracking of carrier and phase is phase locke-d loop.In the condition of grasping PLL principle,Costas carrier synchronization and digital synchronization algorithm is mainly studied.On this biasis,overall design of sy-nchronization system based on PLL is presented.BPSK signal transmission subsystem,wireless channel of simulation module,car-rier synchronization and demodulation sunsystem and bit synchronization subsystem are included in the design.Baseband signal and local carrier signal is generated by sending subsystem.Frequency control module which simulate noise pulse interference,doppler frequency shift and frequency hopping is adopted to test the performance of carrier syn-chronization system.In synchronization system,Costas loop is used in the system.Mea-nwhile,frequency estimation module is used for aiding capture;dynamically switching filter loop coefficient according to frequency offset.Bit synchronization subsystem is d-esigned with all digital synchronization loop.Hardware description language is used to set up behavioral model in Xilinx IES 14.7.Synplify tool is used to synthesis the design.Modelsim 6.5 is used to simulate the function of the system.After realising facility of the Carrier synchronization,bit synchr-onization and digital demodulation system,the performance on the capture,carrier trac-king and bit synchronization is carried out and the conclusions are given.The results of simulation shows that the system is able to realise the carrier synchronization,bit synchronization and demodulation function.The carrier synchroni-zation system can correctly track the phase step,frequency step and frequency ramp carrier signal.Symbol synchronization and tracking in mobile multipath environment(different transmission delay)is realised in bit synchronization system.