【作者】 李静霞；

【导师】 马福昌；

【作者基本信息】 太原理工大学 ， 电路与系统， 2013， 博士

【摘要】 宽带混沌由于具有宽频带、类噪声、δ型相关曲线等特性,在进行测距技术研究时,具有极高的空间分辨率和良好的抗干扰能力。宽带混沌信号主要有光、电两种产生方式,其中光混沌系统集成度低、价格昂贵、稳定性差,无法广泛的适用于测距领域。电混沌系统由于克服了上述缺点,在测距领域中显示出潜在的优势。本论文围绕微波混沌电路及在测距技术中的应用这一研究课题,完成了如下的研究工作：1.对Colpitts电路进行了数值研究,了解了电路的工作原理,以及各参数对电路混沌状态的影响,为进一步电路设计奠定了基础。2.设计了基于标准型的Colpitts混沌电路,得到了基频频率不同的微波混沌信号。同时,通过调节电路中电压值,观察到一系列丰富的非线性动力学现象。3.设计了改进型Colpitts混沌电路,利用BFG520XR和BFG425W微波三极管,实现了最高基频频率至2GHz的混沌信号。同时,对其非线性特性进行了实验和理论研究,得到了电路状态演变过程的分岔图,实验结果与数值模拟结果一致。4.利用改进型Colpitts电路产生的混沌信号作为探测源,基于混沌信号相关法进行了电缆故障的检测。实现了传输线开路点、阻抗失配以及实际破损等故障检测,并验证了该方法应用于电缆故障在线检测的可行性。实验中,我们采用多次平均和离散消除算法降低了背景噪声,改善了测量结果的信噪比。5.提出了基于改进型的Colpitts混沌电路的空间测距雷达系统的实验方案。将改进型Colpitts电路产生的混沌信号作为探测源,结合相关法测量技术,获得了最远探测距离为7.3m,测量空间分辨率为8cm的空间雷达测距的实验结果。更多还原

【Abstract】 In the ranging technology, wideband chaotic signal possess the advantages of high precision and good antijamming property for its broad spectrum, noise-like waveforms, and delt-like correlation properties. There have been two main methods of wideband chaotic signal generation:photonics or electronic technologies. However, these photonics-based methods are so costly, incompact, and sensitive to environmental fluctuations, which are not suitable for widely application in the ranging detection. Electronic chaotic systems can overcome these shortages above and thus more desirable in practice.Focusing on the research project of microwave chaotic circuit and its applications in ranging technology, this thesis is mainly summarized in the following:1. Numerical study of the principle and the dependence of chaotic oscillation on the circuit parameters are presented, which build the theoretical basis for designing the microwave chaotic circuit. 2. We implement the generation of chaos in a classical Colpitts chaotic oscillator. And Chaos with different fundamental frequencies are observed. Moreover, By tuning of the supply voltages, we observe a series of complex nonlinear dynamics.3. We report an experimental study of the ultrahigh frequency chaotic dynamics in an improved Colpitts oscillator. Reliable and reproducible chaos can be generated at the fundamental frequency up to2GHz using two types of broadband bipolar junction transistors, namely BFG520XR and BFG425W. Furthermore, we experimentally and numerically study the nonlinear dynamical characteristics of the circuit. The bifurcations diagram and some of the typical dynamic states are obtained. The simulation results are consistent well with the experimental results.4. Experimental study of the testing wire fault using electronic chaotic signal is performed. Using chaotic signal generated by the Colpitts oscillator as a probe signal, and the correlation technique as measurement method, we achieve detection of the cable faults such as open circuit, impedance mismatch and real damage. We also demonstrate the ability for testing live cable using this method. Background noise of the measure correlation trace is compressed by using the average method and discrete elimination method, and the signal to noise ratio is improved.5. A novel chaotic radar system based on improved Colpitts oscillator is proposed and studied. By using the chaotic signal as the probe signal, and correlation technique as the measurement method, we achieve a8cm range resolution and a7.3m detection range.更多还原