Pulse Compression chirp ranging system signal processing technology research
|School||Nanjing University of Technology and Engineering|
|Course||Communication and Information System|
|Keywords||Linear Frequency Modulation (LFM) Direct Digital Synthesizer (DDS) Complex programmable Logic Device (CPLD) quadrature demodulation|
LFM signal is a kind of big product of bandwidth and timewidth by nonlinear phasemodulation. It is a widely used technique in radar applications. The bandwidth andtimewidth LFM signal could be independent choose to obtain good distance resolution andspeed resolution. What’s more, LFM signal is insensitive to Doppler frequency shift, whichmeans the signal processing is easy.The Linear Frequency Modulation(LFM) pulse compression signal is analyzed, incombination with engineering application fact, this thesis researches the generation ofLFM signal as well as the engineering design.DDS has Micro-Hertz turning resolution, complete digital control, fast "hoppingspeed" and phase-continuous frequency hops advantages. Complex programmable LogicDevice (CPLD) has short period of design and exploitation, low cost of design and produce,good quality and real time’s checkout advantages. We can not only make the designproduct miniaturization, integration, tranquilization and trustiness, but also have the abilityof program directness on system or chip with CPLD. It makes the electric system on design,exploitation, update and maintenance easier.Lastly, system design is accomplished which based on the need of engineering, theLinear Frequency Modulation pulse signal generator is designed which based on Complexprogrammable Logic Device(CPLD) and Direct Digital Synthesizer(DDS), the digitalpulse compression signal processor is designed which based on quadrature demodulation.We can complete the ROM search table and the DDS module programming by usingISE6.2b software, and carry on the simulation to the program by using Modelsim software.It has confirmed the system design’s accuracy and feasibility. It indicates that system hasthe merit of excellent flexibility and high resolution.