基于DDR SDRAM的CTM算法与实现

高分辨率SAR实时成像的大数据量使得矩阵转置运算量激增,成为算法研究中的重要问题。本文结合DDR SDRAM的内部运行机制和读写时序,提出面向DDR SDRAM的最快列读取CTM(corner turning memory,矩阵转置)和读写均衡CTM算法,在无冗余存储器DDR SDRAM体系中获得满意的效果。     

基于SDRAM的星载SAR星上实时成像转置存储器

论述了合成孔径雷达(Synthetic Aperture Radar,SAR)实时成像处理转置存储器(Corner Turning Memory,CTM)的功能和原理,提出了一种基于SDRAM的星载SAR星上实时成像处理CTM系统实现方案。考虑到星上环境对器件的抗辐照要求,系统选用一片XQB2V500 FPGA做控制器,主存储器选用三片Micron公司的MT48LC16A2 SDRAM。系统采用三页式结构,输入输出并行处理。文章分析了系统输入、输出接口时序,给出了详细的硬件实现和测试结果。实验结果表明该CTM系统方案可行,能够应用在星上实时成像处理器中。     

基于FPGA的DDR控制器的实现

目前,DDR SDRAM因其拥有比SDRAM双倍的数据速率,已经成为存储器的主流,得到了广泛应用。使用Altera公司的Cyclone FPGA芯片设计实现了一个DDR控制器,为微控制器或数字信号处理器与DDR SDRAM之间连接提供了一种方案。详细叙述了其基本结构和设计思想,并给出了DDR控制器的状态转换图和在设计与实现中应注意的几个问题。     

DDR2 SDRAM控制器的设计与实现

本文介绍了DDR2 SDRAM的基本特征,并给出了一种DDR2 SDRAM控制器的设计方法,详述了其基本结构和设计思想,并使用Altera公司的FPGA器件Stratix EP2S30F672C3进行了实现和验证,同时给出了设计与实现中应注意的若干问题.     

基于FPGA的DRR2 SDRAM控制器接口的简化设计方法及实现

DDR2 SDRAM是由DDR SDRAM发展而来的一种新型大容量存储器,正在被越来越多的应用在高速存储系统中。文中介绍了利用MIG软件工具在Xilinx Spartan-3A系列FPGA中实现DDR2 SDRAM控制器的设计方法,详细叙述了其基本原理,并给出了硬件测试结果。     

基于DDR2 SDRAM乒乓双缓冲的高速数据收发系统设计

在高速数据收发系统设计中,首先需要解决的问题是实时数据的高速缓存,然而FPGA内部有限的存储资源无法满足海量数据缓存的要求。为了解决系统中海量数据的缓存问题,系统创新提出了一种基于DDR2 SDRAM的乒乓双缓冲设计方案。方案设计了两路基于DDR2 SDRAM的大容量异步FIFO,通过FPGA内部选择逻辑实现两条通路间的乒乓操作,从而实现数据的高速缓存。实验结果表明,基于DDR2 SDRAM的数据收发系统实现了每路512 Mbit的缓存空间和200 MHz的总线速率,解决了海量数据的高速缓存问题。     

基于FPGA的DDR SDRAM控制器在高速数据采集系统中的应用

实现数据的高速大容量存储是数据采集系统中的一项关键技术。本设计采用Altera公司Cyclone系列的FPGA完成了对DDR SDRAM的控制，以状态机来描述对DDR SDRAM的各种时序操作，设计了DDR SDRAM的数据与命令接口。用控制核来简化对DDR SDRAM的操作，并采用自顶至下模块化的设计方法，将控制核嵌入到整个数据采集系统的控制模块中，完成了数据的高速采集、存储及上传。使用开发软件QuartusⅡ中内嵌的逻辑分析仪Signal TapⅡ对控制器的工作流程进行了验证和调试。最终采集到的数据波形表明，完成了对DDR SDRAM的突发读写操作，达到了预期设计的目标。     

卫星导航接收机中FPGA实现的DDR控制器

DDR SDRAM高容量和高速度的特点使它在需要大量数据累积的卫星导航长周期码直接捕获中具有广阔的应用前景,但是其接口与目前应用的大多数处理器都不兼容。在分析了DDR SDRAM的基本操作原理的基础上,提出了一种基于Virtex4系列FPGA的DDR SDRAM控制器的设计,解决了DDR SDRAM和处理器接口不兼容的问题,并给出了仿真波形和实现结果。     

基于FPGA的SDRAM控制器的设计和实现

为扩展TS-101处理器的外部SDRAM存储空间,提出一种基于FPGA的SDRAM控制器的实现方法。分析了所用SDRAM的特点、原理,介绍了SDRAM控制器的组成框图及各模块功能,给出了读写SDRAM的时序图以及SDRAM存储板的性能参数。FPGA中采用了模块化设计方式,该设计将TS-101处理器的外部SDRAM存储空间扩展至512Mbyte。     

基于FPGA的DDR2 SDRAM接口信号完整性设计与验证

对高速DDR2 SDRAM接口信号进行完整性仿真分析,并根据仿真结果得到相应PCB设计规则,最终通过使用FPGA实现了对大容量DDR2 SDRAM的读写控制,板卡验证测试,达到了预期的效果。     

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