Design And Implementation Of Multi-carrier Phase-coded Radar Signal Generation System

With the development of military technology,modern radars are required to have more complete functions and higher performance.Due to the lack of low interception performance of traditional wideband radar signals,people began to search for new systems of radar signals.As a new type of wideband radar signal,multi-carrier phase-coded OFDM signal(MCPC-OFDM)combines the advantages of low interception,anti-interference,and good imaging performance of phase-encoded signal and OFDM signal,which has aroused widespread concern.The MCPC-OFDM signal generator is an important part of the new system rad ar system.Its design performance determines the performance of the entire radar system to a certain extent.In this paper,the following research work is carried out for wideband radar multi-carrier phase-coded signal generation:(1)Multi-carrier phase-coded signal analysis.This paper studies the time-domain and frequency-domain forms of multi-carrier phase-encoded signals,verifies the orthogonal spectral structure of multi-carrier phase-encoded signals,deduces the ambiguity function of multi-carrier phase-encoded pulse signals,and summarizes the superiority of multi-carrier phase-encoded signals.(2)Analysis of MCPC-OFDM radar signal generation technology.Firstly,the principle of OFDM modulation and the implementation of Inverse Fast Fourier Transform(IFFT)are discussed.Secondly,the MCPC-OFDM signal generation technology based on DDS is derived.Finally,two kinds of generation techniques are analyzed and compared.(3)An engineering implementation scheme of the MCPC-OFDM radar signal generation system based on FPGA+DAC architecture is proposed.Firstly,FPGA Kintex-7 XC7K325 T and AD9129 chips are selected through the analysis of hardware resource consumption and performance requirements of the scheme.Secondly,a method of using multiple DDS IP cores to combine one subcarrier to generate the desired frequency signal is presented.Finally,a MCPC-OFDM radar signal generator based on FPGA+DAC architecture is developed.(4)System function simulation test and error analysis.The generation module is tested by setting the MCPC-OFDM signal parameters.The spectrum data generated by the test is analyzed with MATLAB.Then the system error is analyzed and the amplitude truncation error is tested.After functional simulation testing and verification,the M CPC-OFDM signal generation module designed in this paper can generate high-quality MCPC-OFDM signals,and the number of subcarriers can be arbitrarily changed.