Research And Implementation Of Key Technologies On OFDM System In Wideband HF Communication

The research of this thesis is derived from the project named as “The TechnologyResearch of Wideband HF Data Transmission”. The aim of the project is to carry outburst data transmission under low SNR condition of wideband HF channel. Thetechnologies of the wideband HF data transmission based on OFDM are researched,focusing on the research of the synchronization capture and digital IF technologies. Thedesign and implementation of the synchronization capture module and the digital IFmodule based on FPGA are achieved.A synchronization capture method based on CAZAC sequences is designed in thisthesis, at the same time the algorithms of judging and computing correlative value of thesynchronization are improved, and an adaptive adjudgement method is designed; The IFcarrier wave is produced by the NCO, and the DUC(Digital Up Conversion) andDDC(Digital Down Conversion) are achieved by use of interpolation and decimation;The design and implementation of the synchronization capture, NCO, DUC and DDCmodules based on FPGA are achieved.Finally, all the modules above are simulated by ModelSim, from the ModelSimsimulation waveforms, we can see the functional correctness of the design.