一种基于梳状滤波器原理的重频跟踪方法

面对现代电子战复杂的电磁环境以及不断涌现的新体制雷达,如何快速建立重频跟踪成为一个紧迫问题。利用雷达脉冲的相参性,提出了一种基于梳状滤波器原理的快速跟踪算法,利用重频信息产生梳状预测波门,对缓存的脉冲作同时匹配,解决了丢脉冲情况下的跟踪建立问题。为了将算法效能最优化,提出了一种双数字信号处理（DSP）＋现场可编程门阵列（FPGA ）的并行数据流硬件解决方案。实验结果表明该方法能极大地提高重频跟踪的成功率和降低虚警率。     

一种基于脉冲重频跟踪的信号分选方法

脉冲重频是雷达信号的重要特征之一,能否充分利用雷达信号的脉冲重频信息,直接影响雷达信号分选质量.采用由CPU给出的分选结果,包括最后一个用于分选的脉冲的到达时间,装订现场可编程门阵列(FPGA)关联比较器,利用雷达信号到达时间的相参性,将前后脉冲的到达时间差取余,根据余数判断两脉冲的相参关系,快速建立跟踪,由硬件实现对关联信号的脉冲重频跟踪,提高了速度,实现了信号跟踪的稳定性.     

基于脉冲关联的雷达信号重频分选算法

在重频直方图分析方法基础上，根据时差脉冲对之间的相关性，提出并分析了一种新的雷达脉冲重频分选算法。该算法在统计脉冲时差直方图的同时记录脉冲序号信息，改进了传统重频直方图只能用作重频分选前的辅助分析方法的缺点。与传统的重频分选方法相比，本文提出的方法实现简单、分选效率高、可靠性好，能够适应复杂信号环境和复杂重频体制雷达脉冲的分选要求。通过计算机仿真验证了该算法的性能。     

基于滑动时间窗的雷达脉冲列分选方法

电磁空间中大量存在着相互交错的固定重频雷达脉冲列,例如海面大量舰船发射的导航雷达信号、机载脉冲多普勒雷达在不同时段发射的相干脉冲列等。这些脉冲列以时间片段的形式存在,电子侦察分析系统无法事先确定其起止时刻,给这类雷达的重频参数估计和脉冲分选造成了较大困难。该文首先分析脉冲列的短持续时间特性给传统脉冲分选方法性能造成的负面影响,然后引入滑动时间窗思想来削弱这一影响,并据此提出脉冲重频间隔(PRI)高精度估计和脉冲分选方法。仿真结果验证了新方法的重频参数估计和脉冲分选性能。     

基于最小张树判决域法的雷达重频模式识别

通过简单的序列误差和线性误差判决函数对雷达脉冲重频模式进行初步分析,再将聚类方法中的最小张树算法应用于判决函数中去对雷达信号的重频特征进行分析,从而得到了信号的重频模式,为雷达脉冲重频模式识别提供一种新的分析思路,仿真实验验证了算法的有效性。     

电磁环境复杂度等级评估模型

综合考虑靶场复杂电磁环境适应性试验的特点和实际需求,研究了电磁环境复杂度等级分类和评估方法。首先分析了电子装备类型及电磁环境适应性特点。其次提出基于电子装备类型的电磁环境复杂度等级评定方法,即对于雷达类和通信类设备基于信噪比、侦察类设备基于信号脉冲流分别制定复杂电磁环境等级。第三考虑用频装备天线扫描,给出了电磁环境复杂度等级动态统计分析表达式。该研究可为电磁环境适应性试验和作战指挥研究提供重要支撑。     

基于脉冲神经网络的雷达辐射源调制类型识别

面对日益复杂的电磁环境和层出不穷的新体制雷达,基于人工方式提取雷达辐射源特征难以满足现代认知电子战的需求.为提升雷达辐射源识别的智能化水平,提出一种新的基于脉冲神经网络(Spiking Neuron Network,SNN)进行雷达辐射源调制类型识别的算法.首先利用时频分析的方法,将5种常见雷达时域信号转换为二维灰度图...     

一种对脉冲信号的快速测频测向方法

传统无线电监测对象通常是以通信信号为主的连续信号,而对短时猝发的雷达脉冲信号监测能力有限。本文阐述了一种对脉冲信号的快速测频测向方法,该方法提升了无线电监测设备的电磁环境感知及对象认知能力,可满足现代电磁频谱精细化监测的需求。     

基于DSP和FPGA的多雷达脉冲信号模拟器设计

主要介绍了一种基于PC＋DSP＋FPGA体系结构的多雷达脉冲信号模拟器,能够模拟1—4部常规雷达、重频抖动雷达、重频参差雷达、重频参差抖动雷达、频率捷变雷达等多种体制雷达的混叠脉冲信号,并提供对应的载频编码输出,仿真度高。雷达的部数及每部雷达的参数可通过主控计算机中的主控软件进行设置,使用方便灵活,信号通用性强。该系统可在电子战设备前端微波分系统不参与的条件下,为后级数据处理分系统调试提供逼真的雷达测试信号。     

基于集对分析聚类的雷达信号分选算法

现代电子战场的电磁环境日趋复杂,传统的雷达信号分选方法已经很难完成高密集信号环境下的分选任务.提出一种基于集对分析聚类的雷达信号分选算法,该算法融合集对分析中的同异反模式识别的择近原则和聚类分析的思想,将雷达侦察接收机接收的雷达脉冲信号与知识库中已知雷达脉冲信号组成集对,利用信息熵确定分选参数的权重,通过计算集对之间的同异反联系度实现雷达信号分选.仿真实验证明了算法的有效性和可行性,为解决复杂电磁环境下雷达信号分选问题提供了新途径.     

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.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

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.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

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.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.