基于C8051F350的多路高精度数据采集系统及应用

为针对一般的数据采集系统精度较低、价格较高的问题,设计了一种低成本、高精度的多路数据采集系统.系统由上、下位机两部分组成,上、下位机通过RS-485总线进行通信.下位机选用C8051F350作为主控制器,A/D转换采用C8051F350内部24位∑-△型ADC,并设计了RS-485总线接口,便于接入RS-485总线网络.上位机软件使用LabVIEW编写,具有较好的人机交互界面.实际使用表明,该系统能够满足高精度数据采集的要求.     

基于单片机的多路数据采集系统设计

数据采集系统在石油化工行业广泛应用,文章给出一种ATmega16单片机控制的多路数据采集系统的设计方案。单片机将现场采集的多路模拟信号转换为数字量,通过LCD12864将其在现场显示,通过AT24C64将数据进行存储,现场采集的信号还可以通过485总线传输至上位机。     

基于RS 485总线的ADS1258数据采集网络系统设计与实现

针对在航天测试领域中对多个地点处多路模拟信号进行精确采集的需求,设计了相距1 m的6个传感器节点,每个节点10路模拟信号的采集系统。该系统以Spartan-6 FPGA为核心芯片,控制24位精度的模数转换模块、40 Mb/s传输速率的RS 485总线传输模块和USB接口模块的工作,大大简化了以前的测试系统,并提高了采集数据的可靠性和系统工作的稳定性,可广泛应用于对精度要求较高的航天测试系统。     

多冗余输出的数据采集处理单元设计与实现

为解决多通道数据的远程采集和多路冗余输出问题,介绍基于RS 485总线的多冗余数据采集处理单元设计方法,给出4-20 mA采集模块、多路冗余输出处理模块的设计实现,该单元具有通用性、可扩展性强,冗余度高的特点。     

基于RS485的大气数据前端传输系统设计与实现

为了在工农业生产中获取大气数据的详细信息,设计了一种利用RS 485总线把数据采集前端机、子站与中心站互连构成的数据前端传输系统,该系统的前端机对现场大气数据的采集与处理,并通过串口实现与子站、中心站的信息传输,有效完成大气数据的获取与传输.实际测试可见,系统实现了大气数据的采集与传输,可以满足实际工农业生产中获取大气数据的需要.     

基于LXI总线的数据采集系统数据同步方法研究

对于大型的航空发动机数据采集系统而言,需要采集的信号众多.其不仅仅是不同设备信号的简单叠加,还要求不同设备信号间具有更高精度数据同步能力.LXI总线是新一代的仪器总线,其基于开放的工业网络标准,具有分布式的架构、高速的数据传输、高精度的系统同步等优势.某型航空发动机数据采集系统基于LXI总线设备进行设计和组建,充分利用了LXI总线的优点,有效解决了大型数据采集系统数据同步的问题,提高了系统的精度和测试效率.     

基于FPGA的多通道高速信号采集器的设计

采用FPGA技术设计的高速数据采集器可实现采集高速信号并实现实时上报的功能。利用FPGA,外部只需添加简单的电平转化电路即可灵活实现多通道、多主机、多路径实时数据传递。该系统信号采集速度快,接口类型多样,当应用到工业现场后还可以通过RS485总线进行远程升级来满足后续工程的需要而不需要对硬件做任何更改,比传统的数据采集系统有更强的竞争优势。     

基于RS 485总线的数据采集处理系统

为了解决多通道数据的远程采集和处理问题,介绍基于RS 485总线的串行通信数据采集处理系统的方案设计。给出RS 485通信接口的具体硬件电路,应用VC 6.0编写PC机软件,完成了PC机与数据采集模块的串行通信及数据处理的软件系统设计,实现了对多通道现场数据的实时采集和处理,系统具有较强的实用性和扩展性。     

基于RS485通信的远程数据采集与控制系统设计

文章设计了基于RS485通信的远程数据采集与控制系统。系统采用1个主机和3个从机的总线型主从式结构,主从机都采用STC89C52单片机为主控制器,主从机之间的通信电路通过1对双绞线连接,3个从机把温度、湿度、压力信号通过RS485总线传输给主机,主机对数据进行相应的处理。各从机都有唯一的地址字节,主机可通过寻址的方式查询从机设备并发送相应的命令,实现了对多路现场数据的实时采集和现场设备的控制,系统具有较强的拓展性和实用性,且造价较低。     

基于CAN总线的数据采集节点的设计

CAN总线以其自身的技术特点和良好的性能在现代测控领域得到了广泛的应用,本文介绍了一种基于CAN总线的数据采集节点的设计方案,给出了系统总体设计和节点的基本结构,详细说明了以MSP430F449单片机、SJA1000为核心的节点的硬件及软件设计。可在CAN总线上挂载多个数据采集节点,解决了多个节点之间的通信问题。研究表明该方案具有硬件结构简单、成本低廉、采集精度高、抗干扰能力强等优点,实现了数据采集系统的网络化。     

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.     

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.     

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.     

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.     

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.     

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.