基于稀疏超指数盲均衡的高频外辐射源雷达发射信号提取

基于天波雷达发射信号的外辐射源雷达需要在接收站提取发射信号用于匹配滤波处理, 而到达接收站的发射信号往往受到电离层反射与折射多径污染的问题, 提出了一种基于超指数与常数模盲均衡算法的发射信号混合盲反卷积方法.利用电离层折射与反射等多径杂波的稀疏性, 采用稀疏处理降低混合算法中超指数盲均衡算法的计算量, 从而实现发射信号的恢复.针对发射信号恢复质量对检测性能的影响进行了分析评估.计算机仿真表明, 所提出的盲均衡算法保持了超指数算法快速收敛的优点, 同时, 在性能损失很小的情况下计算量显著下降, 具有良好的工程应用前景.     

基于正交小波变换的变步长盲均衡算法研究

针对常数模算法(CMA)剩余误差大与收敛速度慢的问题,将变步长思想和正交小波变换引入到常数模盲均衡算法中,提出了基于正交小波变换的指数型变步长常数模盲均衡算法(WT-VCMA)。水声信道仿真结果表明:与基于剩余误差的指数型变步长常数模盲均衡算法(VCMA)及常规常数模算法(CMA)相比,新算法具有更快的收敛速度和更小的剩余误差。     

一种无源双基地雷达直达波恢复方法研究

在山地及城市附近的应用中,严重的多径杂波造成基于调频广播的无源双基地雷达直达波信号恢复困难。文中提出了采用基于空间分集的常数模盲均衡算法,利用空间分集的多通道,实现信号衰落的补偿,而利用常数模盲均衡算法,实现恒模的调频广播信号的反卷积运算,从而完成了对多径的抑制,获得高质量的直达波信号。计算机仿真表明：与无分集的常数模盲均衡算法相比,所提算法获得了更好的目标检测性能。     

适用于水声信道的快速判决反馈盲均衡算法研究

基于对常数模判决反馈算法(CMDFE)进行分析,提出了一种能够快速收敛的判决反馈盲均衡算法。该算法中构造了一种与常数模算法不同的、能够快速收敛的误差函数,并利用该误差函数对前向权进行调整,而反馈权的调整仍使用常数模误差项。前向权和反馈权系数的更新取不同的步长值。最后通过水声信道模型仿真,对这几种算法进行了数值分析研究。结果表明：所提出的算法可有效地实现对多途水声信道的均衡,并且其收敛速度高于常数模算法和常模判决反馈算法。     

一种快速收敛的水声信道分数间隔盲均衡算法

为了加快常数模盲均衡算法(CMA)的收敛速度并降低剩余均方误差,提出了一种快速收敛的分数间隔常数模算法。新算法采用T/2分数间隔均衡器,针对水声通信中常用的BPSK信号,设计了一个新的误差函数,取代常数模算法中的误差函数。最后,采用浅海水声信道进行了仿真,结果表明,新算法性能稳定;收敛速度高于常数模算法和分数间隔常数模算法;剩余均方误差与分数间隔常数模算法处于同一水平。     

瑞利衰落电离层信道的自适应盲均衡

研究通过具有加性高斯白噪声的瑞利慢衰落电离层信道的恒模盲均衡技术。著名的恒模算法(CMA)是一种重要的盲信道均衡方法。但是，普通恒模算法存在收敛速度慢和相位旋转等不足。采用一种修正恒模算法(MCMA)，该算法使修正的误差函数最小并且自适应学习率由接收序列即时调整。两种算法用8—PSK信号进行了盲均衡比较，模拟结果显示修正恒模算法比普通恒模算法的收敛速度快，符号间干扰(ISI)小，另外该算法均衡器输出具有既无相位旋转也无延迟等优点。     

基于坐标变换的常数模盲均衡新算法

结合信号星座图特点,对常数模算法的代价函数进行修正,提出了基于坐标变换的常数模盲均衡新算法.该算法通过坐标变换将发射信号的模值转换成零,从而克服了常数模算法在对非常模信号进行均衡时,输出误差无法收敛至零的缺点;并且该算法可以在未知发射信号调制类型的情况下完成均衡.理论分析和仿真结果证明了新算法的优良性能.     

基于预测原理的回声状态网络在线盲均衡算法

针对非线性信道,基于预测原理提出了回声状态网络(ESN)在线盲均衡算法,首先将具有良好非线性映射能力的ESN代替传统的线性预测误差滤波器,并采用递归最小二乘(RLS)算法计算网络的输出权值,使网络预测误差达到最小;然后进行幅值和相位的调整。仿真实验表明,对于16QAM信号,所提算法可以有效降低非线性信道对发送信号产生的畸变。与其他基于预测原理的盲均衡算法相比,所提算法有更低的均方误差值和更快的收敛速度。     

多径衰落环境中具有调制识别能力的盲均衡新算法

常数模盲均衡算法在对非常模信号进行均衡时稳态均方误差不能收敛至零,且不具备信号调制识别能力.因此,依照常数模算法代价函数的构造方法定义了一种余弦代价函数,提出了基于该代价函数的盲均衡新算法.该余弦代价函数可将BPSK、M-PAM、M-QAM信号的不同星座点映射至原点,从而使新算法在对上述常模或非常模信号进行均衡时稳态均方误差均能收敛至零,更重要的是新算法能够在多径衰落环境下实现对上述信号的调制识别.理论分析和仿真结果证明了新算法的优良性能.     

基于RENYI熵的水声信道判决反馈盲均衡算法研究

在水下通信系统中,为了抑制由多径效应产生的严重码间干扰,必须进行信道均衡。针对传统的常数模判决反馈盲均衡(CMA-DFE)收敛速度较慢的问题,该文提出了一种基于RENYI熵的判决反馈盲均衡算法(RENYI-DFE)。该算法使用RENYI熵算法调节均衡器前向权向量,用CMA算法调节均衡器反馈权向量,与CMA-DFE相比,该算法在计算量增加很小的情况下,使得盲均衡算法的收敛速度显著增加。仿真结果证明了该算法的优越性。     

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.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

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.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.