Research And Design Of The Multifunctional Radar Signal Source

In recent years, with the application of computer simulation technology and the digital technology, the design of radar waveform generator which is comleted by the combination of computer and programmable chips has been used in radar system tests and widely adopted in different radar systems.The coordination of software and hardware system design can realize the flexible digital signal processing. It makes the synthetic digital waveform has a strict stability and reconfigurability etc and can change waveform parameter of the input flexibilitily. So the research of the radar waveform digital synthesis technology has the very vital significance.The object of the radar signal simulation is the radar transmittion signal and radar echo signal. the radar transmitting signal is directed to radar target environmental characteristics produce a variety of waveforms form, and has a bandwidth and pulse width of the transmit waveform, radar echo signal is reproduced radar target and environment information signal, in the function not only can realize linear frequency modulation, nonlinear frequency modulation signal and other signals in the form of simulation, but also has a corresponding digital up converter (DUC) modulation and Doppler modulation.Acorrding to Radar signal simulation theory,this dissertation focuses on the simulation of the radar signals based on direct digital waveform synthesis technology (DDWS), that is to store data waveform baseband firstly and then the number frequency conversion chip to produce a desired intermediate frequency signal, and then the chip internal DAC simulate the signal output at the same time, in order to control alone waveform parameter, finish parameters of control interface by PC,also can take in the FPGA done inside the logic of data waveform design.This dissertation focuses on the simulation of the radar signal.In the logical development,the following several software solutions are used to meet the needs of the signal generator. According to the simulation theory of the radar signal, inside the FPGA to finish the compile of clutter baseband module and logical time-sequenced control and then use the subsequent digital frequency conversion chips to complete the output of intermediate frequency analog signal and complete the software simulation in the system design.At the same time, use the SOPC piece system to customize NIOS Ⅱ processor and peripheral equipment flexibly, use NIOS Ⅱ processor to complete the download of waveform data, the control of waveform parameter and the realization of the PC communication protocol.The primary work in this dissertation:1.The dissertation introduces the basic theory of the radar signal and the development of the technology of frequency synthesis.2. Analysis the principle and superiority of zero memory non-linearity(ZMNL) and Spherically Invariant Random Process (SIRP),introduces the different distribution clutter design,and completed the clutter simulation based on ZMNL.3.Complete the case design and logical design of multi function radar signal source,this dissertation based on direct digital waveform synthesis technology (DDWS) realize simulation of the radar signal and the radar signal based on FPGA complete clutter baseband module design.4.After completing the research and design of the system,we carried out the software testing and analysis of the system,and verifies the feasibility of the system design.