【作者】 王军；

【作者基本信息】 电子科技大学 ， 通信与电子系统， 1999， 博士

【摘要】 本文从双端口网络等效噪声模型为依托，通过采用精密测量所得的全参数E_n—I_n模型描述有源器件的噪声，以有效地提高低噪声放大器的设计精度；并通过研究E_n—I_n模型与其它六种等效噪声模型的谱关系实现复杂噪声网络的模块化分析与设计，从而简化了噪声估算的过程。希望通过本文研究能开发出适用于复杂电路低噪声优化设计的CAD软件，并使它具有规范、通用性强、精度高和运算快速的优点。 全文共分四章。在第一章中，应用全参数E_n—I_n噪声模型精确计算了低噪声设计参数，如等效输入噪声电压E_ni、最佳源阻抗Z_sopt和最小噪声系数F_min，并指出忽略噪声相关系数γ的影响会造成最大30％的计算误差。在第三章中，介绍了基于E_n—I_n模型的模块化分析与设计理论，并着重解决了多级噪声网络的E_n—I_n模型的综合问题与晶体管放大器偏置电路的噪声计算问题。在第三章中，进行了实验分析，验证了本文方法在低、高频分立电路和集成运放电路噪声分析中应用的可行性，并得到了一些有益的结果。在第四章中，进行了全文总结。 最后，在本文附录中，通过比较两种具有不同雷达带宽和方位角扇区的雷达体制之信号采集与处理的特点，进而指出使用基于窄带宽和小方位角扇区所采集的雷达散射场数据，适于快速、简便的二维雷达目标成像和目标识别。在低分辨率雷达条件下，根据电磁散射理论和衍射身体理论，对二维雷达目标进行参数化建模。该模型系统地描述了目标的散射中心特征，它包括散射中心在距离向和方位向的定位、散射强度和表征散射中心几何形态的衍射系数，因此，它可用于高保真的雷达目标成像和识别。并通过研究该模型与Prony模型之间的关系，给出了一种提取该模型参数的高分辨率估计算法。Cramer—Rao限分析和仿真结果表明所给方法具有良好的统计性能。仿真分析还指出散射中心衍射系数的精确提取受到信噪比、雷达中心频率和雷达带宽等因素的限制。更多还原

【Abstract】 Based on the equivalent noise models of two port network, this report improves effectively the design accuracy of low-noise amplifier using the com- plete EI, noise model of active devices obtained by the precision measure- ment ; and the noise estimation process is simplified using the modularized anal- ysis and design of complex noise network achieved by researching into the spectral relations between the E model and the other six kinds of equiva- lent noise models. It is desired to exploit the CAD software for low-noise op.- timum design of complex circuits based on research here ,and to made it with the advantages such as standard ,high univaersality,high accuracy and fast cal- culation. This report Consists of four chapters. In the first chapter, the parameters for the low-noise design scuh as the equivalent input noise voltoge E~ ,the op- timum source impedance Z and the minimum noise figure F~ are calculated accurately by using the complete E noise model. And it is pointed out that it will cause the maximum 30 4 miscalculation error when neglecting the ef- fects of the correlation coefficient Y. Moreover, the relation of EL model and RG model is built. In the second chapter, the theory of modularized analysis and design based on the EL model is presented. And the main work is focused on the problem of the synthesis of E models of multistage noise network and of the noise calculation of bias circuit of transistor amplifier. In the third chapter , the feasibility of the method here in the application of the noise analysis of low and high frequencies discrete circuit as well as integrated operationl amplifier is verified via the experiment analysis. And some useful re- suits are obtained. In the fourth chapter,the conclusions of this report are sum- marized. At last ,through comparing the characteristics of signal collection and pro cessing of two kinds of radar systems with the different radar bandwidth and aspact angle sector, the appendix of this report points out that the scattering field data collected by using the radar with narrow bandwidth and small aspect angle sector is suitable to fast, handy two ?dimensional radar target imaging and recognition. On the conditions of lowesolution radar ,a parametric mod- el for twoimensional radar target is described according to the theory of el-ectrornagentic scattering and the geometrical theory of diffraction. This modelis sPecial to high precision radar target imaging and identification since it sys-tematically describes the scattering center attributes of target which include.high resolution distance and azimuth locations,scattering level and diffractioncoeffcient characterizing the geometry of scattering center. A high resolutionestirnation algorithm to extract the model parameters is also developed bybuilding the relation of the scattering model and Prony model. The analysis ofCramer--Rao bound and simulation show that the method here has better sta-tistical perforrnance. The simulated analysis also indicates that the accurate ex-traction of the diffraction coefficient of scattering center is restricted by signal--to--noise ration,radar center frequency and radar bandwidth.更多还原