定位预测方程的解析求解研究

研究了定位观测方程的解析求解方法，利用所得方法，在给定目标星座条件下，对定位观测方程的求解进行了仿真。结果表明：解析方法不能直接应用于定位观测方程的求解中，但将解析方法和数值方法相结合，可显著改善求解性能。     

定位观测方程的解析求解研究

研究了定位观测方程的解析求解方法,利用所得方法,在给定目标星座条件下,对定位观测方程的求解进行了仿真。结果表明:解析方法不能直接应用于定位观测方程的求解中,但将解析方法和数值方法相结合,可显著改善求解性能。     

基于MATLAB的换能器阵列指向性分析方法研究

针对复杂换能器阵列解析方法求解指向性较为困难的问题,提出一种基于MATLAB的三维指向性图快速确定定向面,以定向面内的二维指向性图确定指向性关键性能参数的求解方法,从而避免了复杂的解析求解过程,克服了解析方法无法求解时需制作换能器实物阵进行测试的难题。这种方法对于缩短产品研发周期、降低研发成本与研究难度具有实际意义。     

微加速度传感器气膜运动方程的求解

用解析法求解了微结构加速度传感器气膜运动方程，其结果可用于微传感器的结构设计和系统分析。     

异质结双极晶体管基区复合电流的解析模型

从求解异质结双极晶体管基区的二维电流连续性方程出发，推导出了基区少数载流子浓度的解析解，由此获得了基区各处复合电流的解析表达式。基于该模型完成了算法研究和软件编制，计算出了器件所能达到理论电流增益。     

一种基于载流子的双栅MOSFET解析模型

提出一种全新的基于载流子求解的双栅MOSFET解析模型. 针对无掺杂对称双栅MOSFET结构，该模型由求解泊松方程的载流子分布和Pao-Sah电流形式直接发展而来. 发展的解析模型完全基于MOSFET的基本器件物理进行直接推导,结果覆盖了双栅 MOSFET所有的工作区:从亚阈到强反型和从线性到饱和区,不需要任何额外假设和拟合参数. 模型的预言结果被2D数值模拟很好地验证，表明该解析模型是一个理想的双栅MOSFET建模架构.     

异质结双极晶体管基区复合电流的解析模型

从求解异质结双极晶体管基区的二维电流连续性方程出发，推导出了基区少数载流子浓度的解析解，由此获得了基区各种复合电流的解析表达式。基于该模型完成了算法研究和软件编制，计算出了器件所能达到的理论电流增益。     

5G上行TDOA定位算法的仿真和分析

3GPP 5G标准协议在R16版本制订了使用5G无线基站进行精确定位的需求和性能指标,并在R17版本进行了定位技术增强的描述。基于TDOA(Time Difference of Arrival)定位算法,归纳和推导直接解析方法和迭代方法求解双曲线构成的非线性方程组。同时面向5G室内和室外两个简化的应用场景,分别在二维平面和三维空间对算法的求解精度进行了仿真分析。仿真结果表明直接解析方法在二维平面上使用三个基站进行定位,三维空间上使用四个基站进行定位,室内和室外场景能够符合3GPP规定的性能指标。迭代方法在二维平面上室内和室外场景符合3GPP性能指标,但在三维空间上无法符合3GPP规定的性能指标。提出对三维空间上四基站定位算法的迭代方法的改进,引入初始统计的求解算法来设置迭代方法的初值,提升定位性能。进一步的仿真结果表明,改进后5G上行TDOA定位求解的迭代算法在三维空间的求解精度符合3GPP规定的性能指标。分析的多种TDOA求解算法也给5G基站的软件产品在x86或arm平台的实现提供了多样化选择,x86处理器和飞腾处理器上的性能测试表明,TDOA直接解析方法和迭代法实现为软件产品程序模块后,均可以在微秒级别完成计算。     

离散系统状态方程时域解中一个容易忽略的问题

本文讨论了离散系统动态方程求解中的k值范围，纠正了当前某些教材在应用中存在的问题，给出了确切的解析表示方法，以便澄清学生在学习中的模糊认识。     

变边界条件下的电磁场边值问题解析研究

对于变边界条件的电磁场边值问题求解,由于其相应解析解表达式中的系数确定较为困难,通常都是采用数值计算的方法。文中通过对一道变边界条件电磁场分布问题使用分离变量法求解析解,灵活使用了对应系数相等的思想,得到完善解析解。求解过程中具体应用了复数对应相等,实数指数对应相等,弦函数与其复变数间的切换等方法,为求解类似问题探索了一条途径。     

大功率毫米波行波管AM/PM转换特性大信号解析理论的研究

毫米波行波管是未来通信发展的重要方向,由于AM/PM转换是影响毫米波行波管通信的重要非线性特性指标,因此AM/PM转换的研究对实现毫米波行波管线性化具有重要意义．本文基于相位展开的毫米波行波管欧拉大信号注波互作用理论模型,忽略高于二阶的非线性项,建立简化的欧拉大信号注波互作用理论模型．采用逐次逼近法推导其解析解,建立二阶逼近的欧拉大信号解析理论模型．利用欧拉大信号解析理论模型推导AM/PM转换的解析解,并发现AM/PM转换的产生与电子相位直流分量的激励成正比．应用建立的欧拉大信号解析理论和AM/PM转换解析模型对一支Q波段毫米波行波管进行大信号分析,并与拉格朗日理论模型以及传统的欧拉非线性理论模型进行对比．结果表明：欧拉大信号解析解的功率、增益和相移以及AM/PM转换与拉格朗日理论在线性区和中度互作用区十分吻合,饱和增益最大误差小于8.5%．同时,相较于传统的欧拉非线性模型,欧拉大信号解析解对非线性区增益和相移非线性特性的描述更具优势,即不但具有更高的精度,而且表现出传统欧拉非线性模型无法描述的增益压缩和相位失真现象．仿真结果验证了欧拉大信号解析解和AM/PM转换解析模型在线性区到中度互作用区的正确性和有效性．该AM/PM转换解析模型为后续研究毫米波行波管AM/PM转换非线性特性的物理机制与抑制方法奠定了基础．     

Microbending loss in monomode fibres: solution of petermann's auxiliary function

The spot sizes and auxiliary function that determine the microbending sensitivity of monomode fibres are shown to have analytic solutions for step-index profiles. Although a numerical solution is necessary in the core when the profile is inhomogeneous, the derivation is simplified by matching to the analytic solution within the cladding. Previously, analytic solutions had only been given for Gaussian fields.     

Median-prefiltering-based robust acquisition of direct-sequencespread-spectrum signals in wide-band pulse jamming

We propose robust acquisition schemes for chip time-synchronous direct-sequence spread-spectrum (DS/SS) signals in wide-band pulse jamming. To mitigate the performance degradation due to the impulse-like wide-band jamming signal, the received signal is preprocessed by employing simple order statistic filters. We consider the use of two types of median filtering schemes: a running median filter operating at a chip rate and a block median filter processing the received signal sampled at an oversampling rate. For analytic design, the partial correlation of median filtered pseudonoise (PN) signals is approximated by a piecewise linear model using an upper bound. The analytic design is verified by computer simulation. Finally, the acquisition performance of the proposed schemes is compared to that of conventional schemes     

基于符号检测器的修正双模融合检测算法

针对双模复合制导中的融合检测问题,提出了一种修正的符号检测器融合检测算法。通过对两局部统计量增加一个修正系数并使用修正的检验统计量进行判决,融合后系统的检测性能比传统符号检测器融合检测算法有明显提高。文中给出了修正系数和融合检测器的虚警概率表达式,仿真结果表明,文中提出的算法使检测概率比传统符号检测器略有下降,但虚警概率却大大降低,修正算法检测性能有很大改善,仿真结果还验证了修正系数和虚警概率关系的正确性。     

Sample cumulants of stationary processes: asymptotic results

In this paper, we present the formulas of the covariances of the second-, third-, and fourth-order sample cumulants of stationary processes. These expressions are then used to obtain the analytic performance of FIR system identification methods as a function of the coefficients and the statistics of the input sequence. The lower bound in the variance is also compared for different sets of sample statistics to provide insight about the information carried by each sample statistic. Finally, the effect that the presence of noise has on the accuracy of the estimates is studied analytically. The results are illustrated graphically with plots of the variance of the estimates as a function of the parameters or the signal-to-noise ratio. Monte Carlo simulations are also included to compare their results with the predicted analytic performance     

On the detection of known binary signals in Gaussian noise of exponential covariance

The optimum test statistic for the detection of binary sure signals in stationary Gaussian noise takes a particularly simple form, that of a correlation integral, when the solution, denoted byq(t), of a given integral equation is well behaved(L_{2}). For the case of a rational noise spectrum, a solution of the integral equation can always be obtained if delta functions are admitted. However, it cannot be argued that the test statistic obtained by formally correlating the receiver input with aq(t)which is notL_{2}is optimum. In this paper, a rigorous derivation of the optimum test statistic for the case of exponentially correlated Gaussian noiseR(tau) = sigma^{2} e^{-alpha|tau|}is obtained. It is proved that for the correlation integral solution to yield the optimum test statistic whenq(t)is notL_{2}, it is sufficient that the binary signals have continuous third derivatives. Consideration is then given to the case where a, the bandwidth parameter of the exponentially correlated noise, is described statistically. The test statistic which is optimum in the Neyman-Pearson sense is formulated. Except for the fact that the receiver employsalpha_{infty}(which in general depends on the observed sample function) in place ofalpha, the operations of the optimum detector are unchanged by the uncertainty inalpha. It is then shown that almost all sample functions can be used to yield a perfect estimate ofalpha. Using this estimate ofalpha, a test statistic equivalent to the Neyman-Pearson statistic is obtained.     

面向IP化的传送网接入层解决方案

本文通过对城域传送网网络层次和业务特点的分析,提出适合城域网接入层的拓扑结构和统计复用控制方式。在此基础上,对采用集中控制统计复用的PON技术,如何在接入层环加链的拓扑结构下实现业务保护分析了实现方案。提出PON通过简单的改进并结合波分技术后,不仅具备了业务保护能力,而且具有大容量低成本的特点,能较好的满足面向IP化的传送网接入层的业务发展需求。     

MapInfo软件应用于传输网规划及资源管理的探讨

在介绍MapInfo软件功能和传统传输网规划及资源统计方法缺陷的基础上,从在电子地图上显示传输节点信息、基于MapInfo的管线网络资源库的建立、资源库资源数据的导出等方面阐述了MapInfo软件在传输网络规划中的应用,为传输网络规划中的网络资源统计和分析提供了很好的解决方案。     

An Analytic Model to Account for Quantum–Mechanical Effects of MOSFETs Using a Parabolic Potential Well Approximation

An analytic model to account for the quantum–mechanical effects (QMEs) of the MOSFETs using a parabolic potential well approximation is presented in this paper. Based on the solution of the coupled SchrÖdinger and Poisson equations following the Wentzel–Kramer–Brillouin method, a transcendental equation of the subband energy level has been rigorously derived to obtain an approximate analytic solution for the subband energy levels and the inversion charge centroid. Calculated results from the obtained analytical solution are compared with the previous approximate solutions reported in the literature and the numerically simulated data. A good agreement between the analytical and numerical is obtained, proving the validity of the analytic modeling of QMEs.     

Modeling of distributed parasitics in power FETs

A distributed circuit analysis of power FETs accounting for the lateral source parasitic impedance in addition to the lateral drain and gate parasitic impedances is presented. Both a numerical solution and an exact analytic solution are derived. Using the exact analytic solution, approximate equivalent circuits are derived for FETs of short gate width for two common types of boundary conditions. When the gate and drain terminals are located on opposite sides of the distributed FET, the lateral source parasitic impedance can be represented for short gate width FETs by an equivalent circuit with a negative series impedance in series with the source terminal. The practical consequences on parameter extraction for device modeling are discussed. The availability of an exact analytic solution for the distributed FET should also assist with the synthesis of traveling wave FETs.