利用偶极子组或磁环组估计信号到达角

从描述电磁场基本规律的麦克斯韦方程组出发，分析了现有的利用空间任意分布的偶极子组或磁环组构成的阵列估计信号二维到达角和极化状态方法存在的象限不确定问题，并提出了一种解决方法，借助偶极子组或磁环组构成的等距线阵提供的方向余弦信息解决了上述象限不确定问题。数值仿真结果表明文中方法是简单、有效的。     

“北斗”信号重构的导向矢量实时校正

针对导航应用中阵列天线导向矢量误差导致波束合成器性能恶化甚至失效的问题,提出了一种“北斗”信号重构的导向矢量实时校正算法。该算法利用重构的本地“北斗”参考信号与阵列天线接收信号进行相关解扩处理,然后利用信号子空间与信号正交补空间正交的特性,构造代价函数对各卫星方向的阵列导向矢量进行校正。仿真结果表明,经过校正的导向矢量相位误差从-100°~100°降低到-10°~10°范围内,幅度误差从-10~10 dB降低到-4~2 dB范围内;另外,导向矢量校正后,卫星信号波达方向估计误差在0.2°以内,估计精度大大提高。     

分布式阵列雷达基线位置和相位误差的卫星标校方法

在采用相位干涉测角的分布式阵列雷达系统中,系统阵面相位中心位置误差和相位误差对测角精度影响很大,且阵面相位中心位置与物理中心位置通常不一致,因此需要对其进行精细标准补偿。传统的雷达系统误差校正方法通常采用远场辐射源来对雷达进行校正,但是对于单元间距很大的分布式阵列空间目标监视雷达而言,要实现远场辐射校准往往很难。该文提出一种利用多弧段的精轨卫星精密星历对阵面相位中心位置误差引起的相位误差进行白化,然后搜索相位中心坐标和相位差使匹配方差最小的校正方法,无需使用特定仪器测量,且能很好地标定误差;计算机仿真以及实测数据验证了使用该文校正方法后,测角精度得到了显著提升。     

矢量传感器误差校正与补偿

当阵列模型存在误差时,子空间类方法的高分辨性能会显著下降,因此必须进行有效的校正。由于矢量天线本身的复杂性,其相位误差很难精确校准且原有的基于标量天线相位误差的估计方法已经不再适应于矢量天线。该文在到达角已知情况下,给出了一种估计矢量天线阵列相位误差的新方法,并导出了各通道相位误差的计算公式。最后的数值模拟结果说明了本文方法是简单有效的。     

电磁矢量传感器原位误差校正方法

 现有基于电磁矢量传感器阵列的信号DOA和极化参数联合估计算法,大都假设电磁矢量传感器的三个电偶极子和三个磁偶极子严格指向参考坐标系的三个坐标轴,即不存在原位误差.然而在实际应用场合,电磁矢量传感器是存在原位误差的,因此其实际极化-角度域导向矢量与理想情况下的极化-角度域导向矢量有一定的偏差,导致现有方法的估计性能显著下降,因此必须对原位误差进行校正.通过对存在偏差的极化-角度域导向矢量进行一阶Taylor近似展开,并利用一个辅助校正源,提出了电磁矢量传感器原位误差校正方法,给出了原位误差估计的CRB界.仿真结果验证了该方法的有效性.     

一种新的天线阵列位置误差校正算法

天线阵元的位置误差会影响天线阵元所接收到信号的相位.基于特征值分解的波达方向算法对信号的相位误差非常敏感,因此有必要对阵元的位置误差所带来的接收信号相位误差进行校正.提出了一种基于噪声子空间的最优化算法能有效的校正直线阵列的位置误差.与原方法相比,该算法的优化参数仅为原来的一半,提高了梯度优化算法的收敛速度.数值计算结果表明该算法是有效的.     

阵列天线因随机振动引起的测向误差分析及校准

针对阵列天线受舰船甲板低频机械随机振动引发振子位移变化导致的测向误差问题,建立了天线振子随机振动误差模型,仿真分析了天线阵列3个轴向随机振动模式对测角接收信号的影响,提出了一种基于多个接收机在不同位置同时测量的测角误差校正方法.该方法采用最小二乘法得到多个误差校准矢量,通过调用天线波束指向扇区内校准矢量的方法进行误差补偿,解决了低频随机振动模式下阵列天线测角误差的校准问题.该方法已应用到舰载微波着舰引导系统数据解算中.     

彩色电视接收机测量方法指南(三)

七、色度信号解调误差1.定义色度信号解调误差包括下列三个方面:1)解调角误差系指各同步解调器用的本机副载波相位与被解调色度信号副载波相位的偏差。2)相位配合误差     

一种新的圆环全域校相方法

阐述了多模馈源单脉冲跟踪雷达测角系统相位测量校正方法中校相值不确定度与测量子样数量的关系。给出了该类型测角系统任意象限位置空间偏角相位计算公式,并基于此公式提出一种新的圆环全域校相方法。通过对参考信标进行环绕一整周的多点测量,能够克服传统四点相位测量校正方法校相值不确定度大、置信率低、校相结果受零点对不准影响大和多径干扰误差严重的问题,同时给出了该方法的实际测试验证结果数据。     

基于VSA的微波着陆模拟器角精度校准方法研究

随着矢量信号研究的不断深入和矢量信号分析仪器的广泛使用,基于微波着陆信号包括数字信号和模拟信号的特性,提出了矢量幅度误差与信噪比、相位噪声的数学关系,在微波着陆角精度分析基础上,通过测量模拟器输出信号相位噪声和数据信号 EVM 性能,计算扫描波束信噪比,实现模拟器不同输出信号角精度的标校。试验表明该方法简便、易行,满足微波着陆模拟器输出信号角精度的标校。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks