Design And Implementation Of High Speed IF Vector Signal Generator

With the continuous development of radar technology,the signal source which provides test signal for radar has also been developed rapidly,and more and more test tasks are undertaken in the radar field.Because the functions of radar are different,the signals required for testing are also different.At this time,the traditional general signal source can no longer meet the actual needs,which requires us to design a dedicated signal source for radar.In this paper,a special high-speed IF vector signal source is designed,which is based on the actual test requirements of Aerospace X Institute,to generate standard signal,analog modulation signal and digital modulation signal.Firstly,the basic principle of signal modulation is introduced,the basic method of digital signal modulation is introduced in detail,and the generation of parallel carrier and the principle of polyphase decomposition filtering are deeply studied.The key components in the hardware platform of the system,such as the FPGA chip,D/A converter and clock chip,are selected,and the related circuits are designed.Then the scheme of digital signal modulation is designed,and the detailed simulation is carried out by MATLAB and Simulink.Then the functional modules of the system are designed and implemented on the FPGA,including clock generation,parallel carrier generation,polyphase filtering and so on.Finally,the whole system is tested,including the receiving and analysis of commands,the spectrum testing of various modulation signals,and the frequency shifting time testing of single frequency signals and so on.The test results show that the frequency shifting time of single frequency signal is less than 50 ns,the clutter suppression is greater than 65 d Bc,and the clutter suppression of vector modulation signal is greater than 50 d Bc.All other performance indicators can meet the test requirements of the project.