The Research On IF Signal Generation Technology Of Wideband Radar

In the current radar countermeasures research,in order to simulate the radar signal in the complex and changeable electromagnetic environment,it is necessary to put forward higher requirements for the radar signal simulator,including: wide band,high stability,high agility and the ability of multi-mode output.In this thesis,the generation technology of wideband radar signal is studied against the background of various types of radar signal,which can satisfy the simulation of radar signal under different working modes,so as to provide research methods and functional verification for the development,test and production of wideband radar simulator in complex environment.First of all,aiming at the problem of how to generate radar signal,this thesis conducts modeling and analysis by means of radar if signal and antenna virtual polarization,and conducts simulation according to the signal type and polarization mode of radar signal.Aiming at the problem of how to realize the high-fidelity radar signal in the complex electromagnetic environment,the noise signal and the radar signal distortion model are introduced into the radar signal generation to simulate the radar signal received by the receiver.In distortion analysis of the causes for signal caused by the large broadband signal in the output through a DAC devices across the Nyquist dc distortion problem research,under the mode of zero order to maintain,the cross the Nyquist dc predistortion compensation filter of the former three Nyquist dc signal fading phenomenon,respectively,to compensate,realize sampling rate 0-1.5 times the size of the frequency signal fading compensation.Secondly,aiming at the problem of how to realize wideband radar signal under low sampling clock,the method of wideband radar generation under various modulation modes is realized by using the multi-phase structure to realize the radar signal generation model in parallel.In addition,the parallel mixing structure of the signal,the parallel convolution structure of the convolution modulation and the parallel filter structure of the high-fidelity radar signal are realized by means of the parallel convolution structure,which provides theoretical support and method research for the broadband radar signal generation technology.Then,aiming at the distortion of dual-channel polarization characteristic,the distortion channel signal is corrected by means of parallel filter.In order to solve the problem that the parallel filter consumes too much hardware resources,FFAs parallel convolution structure is used to optimize the design of the filter,and the 16-way parallel optimization filter is designed.The adjustment function of the parallel optimization filter to the channel output amplitude distortion is verified by forward and backward tests.Finally,the whole function of broadband radar signal is tested.Firstly,the hardware and software platform modules and the components of the test equipment are introduced.Secondly,the development environment and the required software chip are briefly introduced.Then the FPGA development is introduced.Finally through the oscilloscope and spectrum instrument of pulse current density,pulse radar signal,signal and linear frequency modulation continuous wave radar signal,phase coded radar signal,frequency agility radar signal and noise signal,polarization modulation characteristics and broadband frequency was tested,and can meet the test requirements,reflects the practical application effect of the broadband technology of radar signal.