基于DDS的LFMCW雷达波形发生器设计与实现

【作者】 雷晓华；

【导师】 杨建宇；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2005， 硕士

【摘要】 随着现代数字技术和超大规模集成电路技术的发展,数字波形合成方法已成为现代雷达系统普遍采用的波形合成方式。数字系统对环境因素不敏感,生成的波形具有严格的相干性和可重复性,尤其突出的是通过改变系统时钟和电路设置能够方便地实现波形的捷变,满足了现代电子战环境中对雷达抗干扰和强生存能力的迫切要求。在数字波形产生技术中,直接数字频率合成(DDS)技术凭其众多优点,已经在军事和民用领域得到了广泛应用,通过基于DDS 的各种波形产生技术,可以实现任意波形的雷达信号产生。本文首先介绍了传统的线性调频信号产生的方法,展示了DDS 技术的优越性。在对DDS 进行理论和性能分析之后,根据某雷达接收系统的总体要求,将现场可编程器件(FPGA)与DDS 技术相结合,成功研制出多波形、多功能的LFMCW雷达波形发生器。文章最后对该系统进行了测试和分析,各项技术指标完全达到了系统总体设计要求。本文完成的工作有:1. 对DDS工作原理、输出信号频谱及杂散分布规律进行了分析讨论,并介 绍了几种杂散抑制方法;2. 根据总体对波形发生器的功能要求、时序要求和接口要求,完成了对雷 达接收系统中波形发生器的方案设计;3. 完成基于FPGA的波形发生器控制模块的VHDL编程和设计仿真;4. 基于FPGA和DDS技术,完成了波形发生器硬件原理图设计、PCB设计制 作及PCB板的调试;5. 对线性调频连续波信号和目标回波模拟信号进行了全面的测试分析,完 成了波形发生器与整个雷达接收系统的联调。更多还原

【Abstract】 With the development of modern digital technology and the Very Large ScaleIntegration electrocircuit(VLSI), the method of digital waveform synthesis is widelyused in radar systems now. The waveform generation using digital system is of strictcoherence, repetitiveness, high stability and programmable capability, which can alsoeasily realize the waveform parameter’s agility and generate arbitrary complicatedwaveforms in order to meet the urgent requirement for anti-interference and strongsurvival ability of radars under modern electronic warfare environments. The DirectDigital Synthesis (DDS) technology is widely used in civil and military affairs.In the beginning of the paper, introducing the traditional radar waveformgeneration method, setting out the merit of DDS, then analyzing the principle andperformance of DDS method. According to project request, combining the FieldProgrammable Gate Array (FPGA) and DDS technologies, implementing a waveformgenerator of LFMCW radar system which can generate variable waveforms andmodes. At the end of the paper, waveform of output are shown and analyzed. The testresults completely meet the system requirements.The primary work in this dissertation:1. Analyzed the principle and distribution rule of spurious in DDS and some methods to reduce the spurious;2. According to project function request and interface request, accomplished the design of the waveform generator implement scheme;3. Accomplished the VHDL programming and simulation of FPGA control module;4. Based on FPGA and DDS technology, accomplished designing of principle circuit and PCB of the waveform generator, and debug the PCB;5. Measured fully and analyzed effectively CW, LFMCW and simulated echo of object signals, accomplished the debug with the radar system.更多还原