基于FPGA可配置m序列发生器的设计与实现

针对某些设计场合对可变m序列的需求,提出并验证了一种基于FPGA的m序列发生器方案。该方案采用线性反馈移位寄存器的结构,可通过外设对发生器的初始状态进行配置来改变所产生的m序列。使用Model Sim仿真软件对此设计进行了仿真,并将该m序列发生器应用于某光跳频保密通信系统中完成了实验验证。结果表明,使用该方案实现的m序列发生器结构简单、易于集成,可产生大量不同的m序列,且具有可动态配置的特点。     

基于FPGA的M序列的设计与实现

扩频序列的设计与实现是CDMA通信中的核心,具有重要的理论价值和广阔的应用前景.文中对伪序列的特性及对m序列发生器进行了分析,并在此基础上给出了M序列发生器的设计结构,同时给出了用VHDL实现M序列的程序流程和仿真波形.     

基于FPGA的多路伪随机序列发生器的设计与实现

传统伪随机序列构成优选对的数目较少，在码分多址系统中的应用受到限制。利用GW48实验平台和QuartusⅡ软件，采用有限域法寻找m序列优选对，以及采用自顶向下的设计方法，设计了一种基于FPGA的多路伪随机序列发生器，即G0LD序列发生器。实验测试结果表明该GOLD序列发生器具有良好的自相关性和互相关性，可广泛应用于通信、密码学、雷达、流媒体处理等领域。     

基于FPGA的简易m序列信号发生器

本系统基于FPGA为控制核心,采用EXCD-XC3S500E开发板及模拟电路,完成了简易数字m序列信号发生器的设计,实现对数字m序列信号的生成与发送。     

基于FPGA的m序列发生器实现

讨论了应用移位寄存器理论实现基于FPGA的伪随机序列发生器的方法,通过理论分析给出了m序列本原多项式与m序列移位寄存器反馈多项式间的关系。同时给出了运用VHDL语言编程,并以Altera的QuartusⅡ软件为开发平台的m序列的仿真波形。     

基于VHDL可编程m序列发生器的研制

提出一种可实现周期／初相位编程控制的m序列发生器逻辑电路的设计方案。给出了VHDL与CPLD的实现方案。程序经编译、仿真、测试后，可以实现设计要求。该器件在MCS51的控制下，实现m序列的周期、初相位的编程变化．     

基于虚拟仪器的任意m序列设计

论述了伪随机m序列的产生原理、特性以及构成方法,利用LabWindows/CVI为开发平台,设计了一种2~22级m序列发生器。仿真结果表明,该系统具有远程通信、界面友好、易于集成和扩展等优点,可实现无线激光通信系统误码率的自动化测试。     

基于FPGA的m序列信号发生器设计

m序列是一种伪随机序列CPN码）,广泛用于数据白噪化、去白噪化、数据传输加密、解密等通信、控制领域。基于FPGA与Verilog硬件描述语言设计并实现了一种数据率按步进可调、低数据误码率、反馈多项式为f（x）=1＋x^3＋x^3＋x^4＋x^8的m序列信号发生器。系统时钟为20MHz,m序列信号发生器输出的数据率为20～100kbps,通过2个按键实现20kbps步进可调与系统复位,输出误码率小于1％。     

基于FPGA的高斯白噪声发生器设计

高斯白噪声发生器用于雷达系统和通信信道的测试,采用现场可编程门阵列（FPGA）实现噪声发生器的设计,在Altera公司的QuartusⅡ软件环境下,进行模块化设计方案,将FPGA实现的功能分为m序列产生模块、FIR数字滤波器模块、DDS模块和合成模块四个主要功能性模块,详细分析了m序列发生算法、FIR滤波算法和DDS算法。应用VHDL语言实现模块功能性设计。该系统采用CycloneⅡ芯片EP2C8N,输出噪声带宽可调,计算量小,可重复性好。     

一种非线性最大长度伪随机序列发生器的设计

伪随机序列在众多领域得到应用,研究伪随机序列的产生具有重要意义.基于m序列,首次提出采用特征函数构造非线性最大长度移位寄存器反馈函数.运用这种方法,构造了一类非线性反馈函数.根据该类反馈函数,设计了非线性伪随机序列发生器,并在FPGA(EPF10K)上得到实现.结果表明,该序列发生器生成的伪随机序列,周期长度,平衡特性、游程特性与m序列相同,非线性度较之得到提高,是难得的序列.     

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.