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Colpitts微波混沌及其雷达应用
Microwave Chaotic Colpitts Oscillation and Its RADAR Applications
【作者】 乔闪；
【导师】 陈抗生；
【作者基本信息】 浙江大学 ， 电子科学与技术， 2007， 博士
【摘要】 Colpitts电路是人们熟知的振荡器电路。作为典型的电容三点式反馈振荡电路，Colpitts电路非常广泛地应用于从极低频到毫米波频段的信号源中。在传统Colpitts电路的应用中，人们关注的是其简谐振荡特性，而尽力抑制其它的非线性效应，以期获得高质量的正弦信号输出。与之对应，本论文关注Colpitts电路更加复杂的非线性特性—混沌，尤其是其微波频段的混沌振荡，并试图利用微波Colpitts混沌电信号超宽带、类噪声的特性，构造一种新体制的混沌雷达系统。本论文首先回顾了电路混沌从低频电路到微波电路的发展历程，全面总结了Colpitts混沌振荡及混沌同步的机理、特点和实现方法；其次，针对微波Colpitts混沌信号所具有的超宽带、类噪声的特点，本文对其雷达信号特性，尤其是模糊函数进行了分析计算，其结果表明，微波Colpitts混沌信号具有类似“图钉形”的模糊函数响应，非常适合用于超宽带或随机信号雷达。最后，本文针对一种直接利用微波Colpitts混沌信号作为雷达信号、利用混沌同步进行雷达信号处理的“全混沌”的雷达信号体制进行了计算机仿真研究。其结果表明，该种体制的雷达可以工作于较低的信噪比环境中，并具有可“多用户”使用的优点。
【Abstract】 Colpitts circuit is a well-known oscillation circuit. As the traditionalcapacitance feed-back oscillator, Colpitts circuits are extremely widely usedin signal sources from very low frequency (VLF) to millimeter wave frequenyband. In traditional applications of Colpitts circuit, what people concerned isthe harmonic resonance, and other complex non-linear effects are purposelysurpressed to obtain high quality sine wave output.In contrast, in this dissertation, what is concerned is the morecomplicated non-linear property-chaos of Colpitts circuit, especiallymicrowave chaotic Colpitts circuit, and the possibility of utilizing theultra-wide band and noise-like spectrum in constructing a new scheme chaoticRADAR system.In this dissertation, the evolution of circuit chaos from low frequency tomicrowave frequency, as well as the principle, analysis and realization ofColpitts’ chaos are firstly summarized. Then, the RADAR signalcharacteristics, especially the ambiguity function of microwave Colpittssignals are analyzed, and the results turn out that such chaotic signal is with a"thumb nail" ambiguity function, implying the potential to be used as RADARsignal. At the last part of this dissertation, a system simulation to a "purechaotic" scheme RADAR, in which the wide band Colpitts chaotic signal isdirectly used as RADAR signal, and chaos synchronization is used in theRADAR signal processing, is performed. The results show that such RADARcan work in an environment of low signal-noise ratio, and has a advantage of"multi-user" property。