Research On Broadband Digital Channelized Instantaneous Autocorrelation Frequency Measurement

In today's complex electromagnetic environment,how to select,identify and measure multi-frequency signals simultaneously is very important in electronic warfare.The frequency of receiving signals is an extremely important parameter.It can reflect the function and use of enemy radar,and intercept the frequency of enemy radar signals to enable us to make targeted technical means.At present,all the frequency measurement algorithms are aimed at single carrier frequency signals,and in today's complex electromagnetic environment,the multiple frequency signals are considered to be received unless the frequency of single carrier frequency is fast enough.This will lead to the failure of the frequency measurement algorithm.In order to solve this problem,an instantaneous autocorrelation frequency measurement method based on channelization is proposed.The main idea is to divide the multiple frequency signals at the same time,and then measure the instantaneous autocorrelation frequency of the single carrier signal in each subchannel.Firstly,the theoretical basis of digital channelized frequency measurement is introduced.It includes signal sampling theory,multirate signal processing principle,multiphase filter bank theory and signal frequency measurement principle,providing theoretical support for the design of subsequent digital channelized receiver structure and instantaneous frequency measurement algorithm.The second,multifrequency signals will be reached at the same time,which will be divided into corresponding sub-channels according to the frequency of each signal.To complete the work,in the second chapter,according to the mixing of filter bank and blind area problem,after mixing without blind area was chosen after comparing the channel segmentation approach,design without aliasing without blind area of the filter and the polyphase filter group efficient structure,and the simulation on the forming,verifies the correctness of design.Then,the existing common instantaneous frequency measurement algorithms are studied,and their advantages and disadvantages are summarized and their applicable range is summarized.Proposed an improved instantaneous self-correlation frequency measurement algorithm,on the basis of the original instantaneous self-correlation frequency measurement algorithm,the improved algorithm optimizes the self-correlation variable of the frequency measurement algorithm.The algorithm optimizes the autocorrelationvariables of the frequency measurement algorithm.On the basis of ensuring the correct frequency measurement,the autocorrelation frequency measurement speed and the frequency measurement accuracy are improved,and the speed and precision of the frequency measurement algorithm(including the absolute accuracy and relative precision)are analyzed.Finally,according to the design of instantaneous frequency measurement algorithm,the hardware implementation module was built in simulink,and the parameters in the simulink module were imported into FPGA through the System Generator.The results of measurement and error(absolute error and relative error)are compared with Matlab simulation results to verify the correctness and efficiency of the design of instantaneous frequency measurement algorithm.