Design And Implementation Of FPGA Module In HF Multi-Channel Fast Frequency Selection System

HF communication is a typical wireless communication by sky wave.It mainly relies on ionosphere reflection to achieve long distance wireless communication.The time-varying of ionosphere leads to the time-varying of HF channel.Therefore,It's important for HF communication to select the frequency at which we can communicate.Based on HF frequency selection and link establishment technology,the channelization processing technology is mainly discussed in this thesis,including single-channel channelization processing method and multi-channel channelization processing method.Firstly,the theory of multi-rate signal processing is introduced in this thesis.The sampling,extraction,interpolation and efficient filter theory are widely used in single-channel channelization and multi-channel channelization.The theory of poly-phase filtering is the basis of poly-phase filtering channelization in multi-channel channelization.Secondly,based on the HF IF digitization hardware platform,the processing of up-conversion from baseband signal to IF signal and down-conversion from IF signal to baseband signal is detailedly introduced in this thesis.Combined with the theory of multi-rate signal processing,the cascade structure of filters in up-down converter,filter parameters and the NCO implemented by CORDIC algorithm is detailedly given in this thesis.Their performance was simulated and analyzed by MATLAB,and the IF digitization system was realized by FPGA.Thirdly,in order to carry out multi-channel signal detection,a multi-channel channelization processing method on the basis of single-channel channelization is given in this thesis.In this method,the HF spectrum is firstly divided into multiple channel groups.The signal in each channel group is a bandpass signal.The bandpass signal is shifted to baseband by orthogonal complex transformation.The sample frequency of each channel group is reduced by multi-level cascade extraction filter.And then poly-phase filtering channelization is carried out.The feasibility of the algorithm is verified by MATLAB simulation results,and the idea of FPGA implementation about this algorithm is given.Finally,the timing relationship of the hardware interface and its FPGA implementation are introduced.