基于多周期极限采样法的极限检测器设计

为解决极限检测器单周期数据采样精确度低的问题,提出了多周期极限采样法。利用多周期极限采样法对极限检测器进行了设计,该极限检测器对周期信号进行5个周期的数据采样,通过极限检测器的FIFO模块、最大最小值寄存器模块、数值比较模块最终得到精确的极限值。最后,利用QUARTUS技术对设计进行了验证,该方法能够准确实现偏移量为3 ns的极限检测。     

高清视频光纤传输技术

为了将一种基于通道链路(Channel Link)技术的专用接口格式的相机高清视频图像进行高速无压缩光纤传输,采用了对相机信号直接高速采样、数据无损处理和编码传输的设计方法.通过自制相机信号源进行传输验证和使用实物相机进行高清视频图像实时传输实验,获得了监视器视频图像显示正常、信号时序无变化的结果,从而表明传输系统满足高清视频图像传输要求,具有高速、无视频丢帧和链路同步快的特点.     

高分辨率全帧CCD高速驱动设计

目前采用高分辨率全帧CCD作为图像传感器的航空遥感相机输出帧频低、驱动设计灵活性低,应用受到限制.为提高全帧CCD相机应用水平,通过FTF5066M驱动电路结构和时序关系分析,采用分离器件设计了全帧CCD的稳压变换电路、偏置电压电路和水平垂直驱动电路.利用FPGA设计了四通道高速并行输出的时序脉冲产生电路,克服了传统单通道输出方法的速度限制.试验中,该驱动电路利用MVC3000F镜头成功采集到高速图像.实验表明,本驱动设计配置灵活,输出帧频从0.7fps提高到2.16fps,充分满足了航空遥感相机的高帧频要求.     

基于CPLD的C8051F单片机高速数据采集系统设计

设计了以CPLD为采集控制单元的高速数据采集系统。此系统采用CPLD对串行AD和串行铁电存储器的进行时序控制,协助芯片单片机C8051F020进行逻辑控制和时序协调。系统可实现采样频率2 MHz、采样精度12-bits、体积小和功耗低。该设计已经成功应用在测试中,其性能和指标均优于应用要求。     

一种频率自适应欠采样电路的设计及FPGA实现

针对数字式锁相环前端A/D单元中,采样时钟在锁相环锁定前存在动态变化的问题,利用16位ADC器件AD7626的特点设计了一种基于FPGA的频率自适应欠采样电路,提出了频率自适应的时序控制策略,解决了FPGA时序控制驱动程序对输入采样信号频率变化的自适应问题。动态欠采样频率下对时基信号进行采样的实验测试结果表明,采集信号频率与理论一致,设计采样电路具有频率自适应特性。     

高速拼接CCD相机时序设计

高速拼接CCD相机是目前我国空间目标监控领域中急需的CCD相机之一,相机的研制对提高我国高速拼接CCD相机的研制能力有很大的推动作用。本文重点介绍了16通道高速拼接CCD相机的时序设计,以及相机的实测结果,并对相机的实际应用前景进行了展望。     

一种高灵敏度制冷型科学级CCD相机的设计

介绍了一种高灵敏度制冷型科学级CCD相机的设计方法.相机利用FPGA芯片实现时序驱动、相机控制及传输数据;设计了相关双采样电路来降低相机的复位噪声;数据由以太网接口芯片W5300通过TCP/IP协议发送到图像采集软件显示和处理.相机采用半导体制冷器结合水冷的方法进行制冷.实验结果表明,在相机制冷到-20℃时,最低照度可达到0.005 Lx,具有灵敏度高的特点,能够满足弱光环境中的使用需求.     

高速高机动弱小目标检测方法研究

本文针对高速高机动弱小目标检测中的距离走动和多普勒走动问题,提出一种多普勒频率补偿加尺度变换的目标检测方法.首先通过多普勒频率估计构建多普勒频率补偿函数,消除速度引起距离走动的影响,其次采用尺度变换方法消除多普勒调频率的影响,从而使积累时间不再受目标运动的限制.该方法无需多普勒调频率估计,解决了传统弱小目标检测方法中多普勒调频率估计准确性问题.在进行多普勒频率估计时,提出一种无模糊多普勒频率估计方法,该方法避免了模糊因子估计,大大减小了计算量,同时降低了对输入信噪比的要求,且有利于多目标情况.仿真结果验证了所提方法大大提高了高速高机动弱小目标的检测性能.     

回波越距离单元走动的MTD研究

针对高速目标回波脉冲信号产生越距离单元走动,动目标检测的MTD方法积累脉冲减少导致检测性能下降的问题,提出一种校正存在多普勒模糊的越距离走动的方法.利用回波信号快时间频率域的积累以及一个CPI内同一距离单元对存在模糊的多普勒的采样特性,结合孙子定理,给出解模糊多普勒的新方法.对CPI每重复周期采样点进行采样补偿,再实现采样数据矩阵沿多普勒斜线的包络对齐.然后利用MTD,实现动目标检测.给出算法框图,通过仿真实验证明该方法的有效性.     

多通道ADC的高速接口设计

针对多通道高速采样器ADS6445的高速串行数据接口特点,提出了一种高速接口的实现方法.使用Xilinx Vertex5系列FPGA接收采样串行数据,利用FPGA的片同步技术通过在线时序调整实现了高速解串;对高速接口的组成及工作原理、片同步技术的特点、设计规则进行了简要介绍,描述了高速接口的时序调整过程;对高速接口的适应能力进行了分析,最后通过仿真及试验验证了接口工作的正确性.     

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.