基于Verilog的多路相干DDS信号源设计

传统的多路同步信号源常采用单片机搭载多片专用DDS芯片配合实现。该技术实现复杂,且在要求各路同步相干可控时难以实现。本文在介绍了DDS原理的基础上,给出了用Verilog_HDl语言实现相干多路DDS的工作原理、设计思路、电路结构。利用Modelsim仿真验证了该设计的正确性,本设计具有调相方便,相位连续,频率稳定度高等优点。     

基于AD9959的多路同步雷达回波信号源设计

提出了一种基于直接数字频率合成器芯片的相位差可调节多路雷达回波信号模拟信号源的设计方法,整个设计以AD9959芯片为核心,采用FPGA器件实现对系统的控制,并最多可同时产生4路中频信号,且每路的频率、相位、幅值均可调。该方案具有设计简单、低成本和便于升级等特点。     

基于调相谱技术的谐振式光纤陀螺检测电路数字化研究

谐振式光纤陀螺(R-FOG)是基于Sagnac效应产生的谐振频率差来测量旋转角速度的一种新型光学传感器.针对调相(PM)谱技术的R-FOG系统方案,研究了基于坐标旋转数字计算机(CORDIC)算法的数字同步检测电路.通过单片可编程逻辑器件(FPGA)可同时实现调制信号产生、同步解调以及信号处理,从而使R-FOG检测系统更加稳定、灵活.对基于CORDIC算法的频率合成技术和同步检测电路做了分析和测试.将设计的数字检测电路应用于R-FOG系统,完成了陀螺转动信号的观测.     

基于FPGA的多路光纤数据同步技术

针对当前相控阵雷达数字TR组件的设计,提出了一种基于光纤信号的同步方法,使得数据传输和雷达主触发同步集成在同一根光纤中,从而省去了传统采用专用触发进行同步控制的大量触发线,简化了相控阵系统有源面阵设计。经在实验板FPGA验证,该光纤同步技术能有效实现多板多片FPGA间的信号同步控制及处理,为后续的数字相控阵有源面阵的同步设计提供了更多的选择空间。     

基于FPGA和AD5628多通道信号源的设计与实现

针对以往多路信号源数模转换模块及后续调理电路的复杂性问题,提出了一种基于FPGA和PCI总线技术的信号源系统设计。以FPGA作为中央控制核心,采用D/A转换器AD5628,围绕其展开系统硬件电路与FPGA逻辑时序设计,实现了多路幅值为-6~6 V可调模拟量信号源的并行输出。测试结果表明,系统输出信号精度高,稳定性强,满足设计要求。     

基于AD5504的多路信号源的设计与实现

针对目前多路信号源DA通道切换及其调理电路的复杂性问题,结合测试系统对于模拟高压信号源的要求,设计了一种基于AD5504的多路模拟信号源。该板卡以FPGA作为系统控制器,PCI9054作为PCI总线协议芯片,信号源包含32路0-28V波形、幅值、占空比可调模拟电压,通过8片四通道DA转换芯片AD5504进行DA转换。经多次测试,该板卡可可靠输出所需模拟电压且达到输出电压误差小于满量程的0.2%,各通道的功率小于0.4W,稳定性高,对于高压模拟信号源的设计有一定的参考价值     

多路同步串口的FPGA传输实现

为适应多路数据接收的需要,设计了一种基于FPGA的多路同步串行数据采集及发送系统.详细讨论了FPGA数据采集部分及发送部分的控制逻辑;FPGA与DSP的通讯,FPGA与ARM的通讯的设计和实现.本系统已成功用硬件实现,其性能和指标均达到应用要求.     

数字化电容层析成像系统没计

基于Xilinx Spartan-3型FPGA芯片,设计了一套数字化电容层析成像数据采集系统.该系统南FPGA构建片内DDS模块,与外部D/A配合,产生激励型号,嵌入于FPGA内部的MCU模块控制多路选通、调节PGA增益并与PC及通讯,FPGA硬线逻辑控制A/D采集并实现数字相敏解调.该系统具有结构灵活、测量精度高以及测量速度快等特点.     

基于Flash型FPGA的信号源卡设计

介绍了一种基于Flash型FPGA的多路模拟量信号源设计方法,该系统以ACTEL公司的A3P125-VQ100芯片为核心,实现了系统的软硬件结合。它包括数模转换单元、电源模块、多路模拟开关模块以及运算放大单元等,实现了电源独立的、频率可调的、不同波形的多路模拟量信号源。该系统通过编写程序可以产生正弦波、三角波、方波以及直流波并实现1～500 Hz频率可调。研究的核心内容主要是通过FPGA控制D/A和多路模拟开关,通过D/A产生波形从多路模拟开关中送出,通过拨码开关在1～500 Hz的频率范围内控制选择,并且能够通过示波器观测到相应的频率的波形。     

基于ＦＰＧＡ的高精度多通道信号源设计与实现

针对航天领域遥测系统设备地面测试阶段需要模拟多种信号,以完成地面模拟试验,设计了一种基于FPGA和千兆以太网的高精度多通道模拟信号源。该信号源以FPGA作为系统的核心控制器,通过千兆以太网接收上位机传输的指令来控制信号的输出,实现了65路0~5V、10路0~28V、8路-15~0V可调直流模拟电压输出、2路TTE网口信号输出和16路RS422数字信号输出。该信号源结构设计简单合理,配套上位机能够对直流电压信号进行幅值设定和精度补偿,能够达到输出幅值精度优于0.01％,同时能够配置数字信号的帧格式和数据内容,能够兼容HDLC、PCM等多种数字协议。试验表明,系统能够实现所需信号的高精度可靠输出,并且具备极高的兼容性,目前,该信号源已经成功应用于某数据采编存储器的地面联试实验。     

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