信号相关杂波背景中极化雷达发射波形优化

波形优化可有效抑制干扰,显著改善雷达探测性能。针对全极化雷达,考虑发射波形满足能量和相似性双重约束,以最大化信杂噪比为准则,对发射波形和接收滤波器进行联合优化。该文设计了一种波形和滤波器的迭代优化算法,该方法序贯提高输出信杂噪比。算法的每一次迭代需要分别解决一个凸问题和隐凸问题,整个算法的计算量与迭代次数和接收滤波器长度分别呈线性和多项式关系。最后,通过仿真实验分析了算法的收敛性、优化波形的模糊度函数方面的性质,与其他算法进行了对比,结果表明:与现有方法相比,该文方法可实现信杂噪比的有效提升。     

信号相关杂波背景中极化雷达发射波形优化

波形优化可有效抑制干扰,显著改善雷达探测性能.针对全极化雷达,考虑发射波形满足能量和相似性双重约束,以最大化信杂噪比为准则,对发射波形和接收滤波器进行联合优化.该文设计了一种波形和滤波器的迭代优化算法,该方法序贯提高输出信杂噪比.算法的每一次迭代需要分别解决一个凸问题和隐凸问题,整个算法的计算量与迭代次数和接收滤波器长度分别呈线性和多项式关系.最后,通过仿真实验分析了算法的收敛性、优化波形的模糊度函数方面的性质,与其他算法进行了对比,结果表明:与现有方法相比,该文方法可实现信杂噪比的有效提升.     

极化雷达输出信杂噪比优化算法研究

通过优化发射波形,可降低各种干扰和噪声对雷达场景信息的影响,从而提高雷达性能,以极化雷达为研究对象,在给定目标特性矩阵Ｔ(θ)、杂波参数和系统噪声υ条件下,采用最大化滤波器输出信杂噪比(Signal Clutter plus Noise Ratio, SCNR)为目标函数,通过优化设计发射波形与接收滤波器?实现了一种迭代优化方法。实验表明,相比现有的Pillai方法,该算法确保了极化雷达最大化输出SCNR的单调收敛性,提高了雷达的输出信杂噪比。     

可用于DSSS系统时变干扰抑制的IIR滤波器设计

在理想的干扰瞬时频率估计条件下,推导Kwan-Martin结构IIR干扰抑制滤波器相关输出信干噪比改善因子的闭合表达式。与五系数时变FIR滤波器干扰抑制性能比较表明,IIR滤波器对DSSS信号的失真远小于FIR滤波器,信干噪比改善因子与干扰瞬时频率及系统扩展比无关,干扰抑制性能优于时变FIR滤波结构。     

卫星导航接收机时域窄带干扰抑制滤波器设计与性能分析

针对卫星导航接收机时域窄带干扰的有效抑制问题,本文首先给出二阶格型IIR陷波器参数设计方法,通过陷波带宽的定量调整,既可以有效抑制窄带干扰,又可以降低卫星信号的失真;其次推导了二阶IIR格型陷波器相关输出信干噪比改善因子的闭合表达式,该表达式相比干扰抑制后信干噪比的改善,更为直观地反映了陷波器对卫星导航信号的影响。理论分析和仿真实验,二阶格型IIR陷波器相关输出信干噪比改善因子与陷波器的带宽参数有关,而与陷波频率无关,且二阶格型IIR陷波器的性能优于最优线性预测Wiener滤波器、最优线性插值Wiener滤波器、五系数FIR滤波器以及二阶直接型IIR陷波器。      

一种基于对角加载的降维多级维纳滤波实现方法

文章以GPS信号抗干扰为背景,应用多级维纳滤波的抗干扰方式。首先分析了经过多级维纳滤波前向迭代后的降维数据矢量的协方差矩阵,给出以特征值和特征矢量表示的最优权值。最优权值的表示式表明在滤波器维数超过最优时高阶的特征值对最优权值影响较大。随后通过仿真试验证明了在滤波器维数超过最优时输出信干噪比会下降。通过引入对角加载量并适当选择加载量功率的大小可以抵消滤波器维数过估计带来的影响,试验表明在对角加载量与白噪声方差相等时可以获得较好的输出信干噪比。文章从空频响应的角度试验了对角加载对于多级维纳滤波算法的意义。最后仿真试验了基于对角加载多级维纳滤波实现方法的抗干扰性能。      

迭代自适应收缩加权融合的波束形成方法

自适应数字波束形成是通过对阵列接收数据进行加权处理来获得最大的输出信干噪比,对采样协方差矩阵的依赖性较大。针对小样本条件下采样协方差矩阵求逆算法性能下降问题,提出迭代自适应加权融合样本协方差矩阵与先验协方差矩阵的波束形成算法。在估计协方差矩阵时,依据最小均方误差准则计算加权系数,并采用迭代自适应的方式更新先验协方差矩阵。仿真结果表明,所提方法能显著提高小样本条件下的协方差矩阵估计精度,能获得更大的输出信干噪比。      

距离多普勒域多雷达信号融合

传统的单雷达目标检测算法在低信杂噪比(SCNR)场景下,其检测性能较差,对低空微弱目标检测时,由于杂波信号很强,目标回波信号可能在单个雷达的回波中被杂波淹没,导致不能检测到目标。所以,文中提出一种多雷达信号融合算法检测动目标,在距离多普勒域对多个雷达回波信号进行融合,增强目标信杂噪比。最后,通过仿真来验证提出的算法的有效性。     

UDN中基于上下行对偶性的分布式干扰协调

针对超密集网络（UDN,Ultra-Dense Networks）中的小区间干扰问题,提出一种基于上下行对偶性的分布式干扰协调方法。首先设计了新的TDD帧格式,在原有LTE标准的基础上加入了信道估计部分与上下行迭代部分;接着利用网络的对偶原理,设计了新的迭代干扰处理算法,将最大化信干噪比和最小化残留干扰相综合,实现最大全网和数据的优化目标。理论分析和仿真结果表明,基于最大信漏噪比准则选取迭代初值时,可在一次迭代后达到较好的和数据率性能;并且该方法能在较短的时间内完成干扰协调,只需要已知局部信道信息,在UDN中易于实现,性能上优于其它分布式迭代干扰处理算法。      

系数矩阵分解二维谱估值

本文提出了一种二维线性预测谱估值的改进方案,在这方案巾,对预测误差滤波器的系数矩阵进行了奇异值分解(SVD),从而可以分析出该矩阵隐函的有效秩,按照这一隐秩可以构成一个近似矩阵来代替原矩阵,这样所获得的谱估值可以抑制峰裂、压缩伪峰,从而使分辨率获得明显的改善,这些改善被实验研证实,此方法可用于因果、半因果、非因果等各类不同的线性预测系统,并且有运算量小及信/噪比要求低等突出优点。     

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