基于MSP430单片机的直流电子负载设计

直流电子负载具有使用方便、灵活,功能强大等特点,能够很好的检测直流稳压电源.因此人们对电子负载的需求越来越多,对其性能要求也越来越高.设计了一种高精度的电子负载,其主要由电子模块、电子负载模块、频率切换模块、采样模块、显示模块和电源模块构成.它是以MSP430单片机为控制中心,通过D/A的控制达到恒流值在一定范围内的控制,通过内含A/D的采集模块将实际的端电压、端电流送回单片机控制模块,还采用了PID控制算法,通过显示模块加以显示电子负载参数.该直流电子负载具有精度达到±1％、分辨率高、实时测量、自动测试等特点.     

基于PXI的高速数字化仪模块

设计了一种基于PXI接口、双通道12位、采样速率250 Msps的高速数字化仪模块,给出该系统的工作原理、设计思想和实现方案,系统采用双通道A/D转换器进行采样,使用高性能FPGA器件进行通道控制、数据处理和接口设计,具有功能强大的前端调理电路,可以选择匹配阻抗和耦合方式、具有增益自动调整功能,满足大范围信号的测量要求.从硬件和软件两个方面对高速数据采集、传输和存储的关键问题进行了深入探讨.该数字化仪模块可方便的与其他PXI仪器组成测试系统,实现对信号的高速采样和长时间记录.     

基于TMS320F2812的数据采集和处理的系统设计

本文阐述了一种基于DSP的数据采集和处理系统的设计和实现,该系统主要采用TI的32位定点数字信号处理芯片TMS320F2812作为信号采集和处理的核心,充分利用该芯片内部的12位的A/D模块对数据进行不同采样频率采集,并且通过事件管理器来启动A/D采样,变频采样速率主要是通过在程序中设置两个变量来控制。数据处理模块充分...     

SC—01型机电系统控制板的设计与实验研究

设计了一种基于AT89C51单片机的SC-01型机电系统控制板。该控制板由AT89C51单片机、程序存储器模块、A/D模块、D/A模块和串行通信模块组成。这里详细介绍了各扩展模块电路的工作特性,并分别对该控制板的CPU模块、D/A模块、A/D模块、串口通信模块进行了实验研究,结果显示该控制板能稳定地实现预期功能。该控制板功能齐全、结构紧凑、经济实用,可以应用于工控领域,也可以用于培训和教学实验。     

在机车横向振动信号模数转化中的应用

基于TMS320LF2407 DSP模数转换模块(ADC)直接应用于机车横向振动信号A/D转化、实现串行高速采样的目的,采用对ADC模数转化进行软件编程的方法,通过合理安排转换通道、设计系统要求的采样频率和A/D转化,通过分析计算和误差分析,DSP ADC能够最大限度缩小串行采样与并行采样之间误差,能够满足DSP控制系统的需要,在设计硬件电路中,完全可以利用DSP集成的DAC模块。     

高精度宽范围数控电流源模块设计

文章设计并制作了一个高精度宽范围数控电流源模块,该模块由逻辑控制电路、D/A转换电路、压控恒流源电路和电压监测保护电路组成,采用可编程逻辑解析处理器的控制字,经过D/A转换控制压控恒流源电路输出电流,同时输出电流通过采样电阻转换成电压送至A/D转换,并与预设值进行比较,以实现高精度、高量程的电流输出。设计的该电流源模块能够满足高精度航空电机的控制需求,具有控制精度高、输出范围宽,降低了设备的重量和体积等优点。     

基于ADS1255的地震信息采集模块设计

为满足地震数据采集系统高精度信息采集的需求,设计一种以24住△-∑型A/D模数转换器ADS1255为核心,高性能数字信号处理器TMS320F2812为主采集控制器的地震信息采集模块,详细给出该模块的硬件电路及其软件设计.该地震信息采集模块具有宽范围的采样输出速率和可靠的采样精度,可广泛应用于高精度采集系统.     

高速任意波形发生器的设计

基于数字频率合成技术给出一种高速任意波形发生器的设计方案,详细介绍各个模块的硬件电路设计以及MCU部分的软件设计.该方案采用高速波形数据存储器、高速D/A转换器以及奇偶数据选择电路,任意波形采样速率可达200 MS/s,任意波形的最高输出频率可以达到50 MHz.针对不同的输出波形,波形输出电路采用七阶椭圆滤波器以及高斯滤波器以减小波形失真.该方案具有输出波形数据不丢失、输出波形稳定等特点.     

一种提高SAR ADC的D/A转换精度的方法

为进一步提高R-C型SAR ADC的转换精度,在传统R-C型D/A转换结构的基础上,增加了一个偏移量模块,引入了小的偏移量。在采样过程中,当输入转换电压发生低于1个有效位的变化时,D/A转换结构能更精确地采样。该改进方法不改变传统电路的基本结构,只需增加很少的元件,就可改善ADC的精度和对零点采样的准确性。对10位R-C型SAR ADC进行了D/A转换和静态参数仿真。结果表明,INL、DNL均在±1 LSB内,证明了改进方法的有效性。该方法可适用于其他位的R-C型D/A采样网络。     

振动环境下建筑工程抗震性检测系统的设计与实现

针对建筑工程抗震性检测系统输出误差较大,功耗高的问题,设计了一种振动环境下的建筑工程抗震性检测系统。该检测系统包括振动信号传感器模块、基线恢复模块、振动数据的时钟采样模块、A/D模块和程序加载模块,对各功能模块进行电路设计,实现振动检测系统的集成设计和软件开发,并应用到工程实践中。分析结果表明,该检测系统对建筑工程的振动数据采样与检测的实时性较好,具有较高的精度,有效指导了建筑工程的抗震设计。     

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.