【作者】 王静雨；

【导师】 冉立新； 皇甫江涛；

【作者基本信息】 浙江大学 ， 电子科学与技术， 2013， 博士

【摘要】 非线性问题是连续波无线测量系统设计中的一个关键课题。本学位论文主要研究连续波无线测量系统中非线性问题的来源,分析其对系统应用的影响,并提出相应的抑制方法。论文首先从系统分析的角度,指出了连续波无线测量系统的线性测量需求,以及系统的非线性组成之间的矛盾。为解决这一矛盾,需要通过数学推导或者实验分析的方式,对系统的非线性子系统进行精确建模,并在此基础上构建严格的逆向子系统。论文进一步指出,系统软硬件设计中常见的非理想因素(如正交解调不平衡、基带信号中的直流偏移和反正切函数值域限制引入的相位截断等),会破坏逆向子系统的构建,并在系统输出中引入额外的非线性分量。为抑制上述典型非线性因素的影响,论文分别采用了数字中频接收机架构,基于最小二乘法的直流偏移补偿算法和扩展DACM算法。在此基础上,论文给出了基于射频仪表的连续波无线测量系统的实现方法。之后,论文介绍了连续波无线测量系统在不同领域中的应用。在介绍无线测量位移与振动的应用中,论文指出利用线性的连续波无线测量系统,不仅能够完成振动频率和速度的测量,还能完成振动幅度的测量,甚至可以实现对振动轨迹的测量。在人体心脏运动微波成像的探索性研究中,实验结果显示,待测者屏住呼吸的测量结果,和医学教科书上给出的理论心脏运动模式相符。为分离测量结果中的心跳与呼吸运动,论文还给出了基于多项式拟合技术的分离方法,并比较了从人体不同方向进行心跳运动成像的结果。在模拟量的近场非接触测量及其应用中,论文实现了对恒温箱内的待测电路进行无线供电和监测的技术。在介绍上述内容时,论文多次指出系统的非线性问题对测量结果具有不利影响。为了进一步拓展连续波无线测量系统的应用范围,有必要对系统线性度问题继续展开深入研究。更多还原

【Abstract】 Nonlinear problems are critical issues in the design of a continuous-wave (CW) wireless mea-surement system. In this dissertation, the source of the nonlinear problems, their impact on the system performance, and corresponding elimination methods have been studied.From a system point of view, it is observed that there is an inherent conflict between the system requirement for linearity and the nonlinear system composition. To solve this problem, it is highly desired to precisely model the nonlinear subsystem through theoretical or experimental analysis, and then construct an inverse subsystem to eliminate the nonlinear issues.However, it should be aware that the non-ideal issues in the system implementation, such as the quadrature channel imbalance, DC-offsets in the baseband signals, and the phase wrapping caused by codomain restriction of the arctangent functions, will do harm to the construction of the inverse subsystem, and introduce additional nonlinear components. Their bad effects have been eliminated or compensated with appropriate methods, with the aid of these methods, an instruments-based CW radar system has been constructed.Then, three promising applications of the CW wireless measurement systems have been in-troduced. In the case of noncontact displacement and vibration detection, it is shown that not only the frequency and velocity, but also the amplitude of vibration can be measured. In addition, the linear CW measurement system is also capable of tracking the displacement trajectory. In an ab-initio investigation of1-D microwave imaging of human cardiac motion, the detected time domain trajectory of cardiac motion fits the theoretical pattern in medical textbooks. A polynomial fitting technique has been proposed to eliminate the respiration motion. And the measurement results from different orientations have been reported. Last but not least, an example of CW measurement system used in near-field analog quantities monitoring has been reported. Not only the data trans-mission through impedance modulation, but also the power transfer via magnetic resonance can be achieved by this system. Be aware that the nonlinear problems will no doubt do harm to the measurement results. In order to extend the application of the CW wireless measurement system, it is essential to maintain its linearity.更多还原