一种快速CRC 算法①的硬件实现方法

介绍了CRC校验算法的硬件电路实现方法。CRC校验广泛应用于通信、存储系统，在串行CRC实现的基础上，对电路结构提出了改进的方案，并实现了CRC的并行计算，由此进一步可以适用于任意位数据宽度的数据输入情况。     

Xmodem协议中CRC算法的FPAG实现

基于解决Xmodem协议中CRC校验的目的,以经典的LFSR硬件电路为基础,采用了按字节并行运算CRC校验码,以及多字节CRC算法的方法。在Quartus II环境下,通过以VHDL语言仿真试验,得出Xmodem协议中CRC校验,以多字节循环并行CRC算法能够满足高速实时性要求的结论。     

基于FPGA的16bit CRC校验查表法设计

针对串行通信过程中常用的CRC校验,在Xilinx ISE 10.1中采用IP核建立RAM,用以存入16 bit CRC校验余式表中的CRC校验码,采用VHDL语言完成了16 bit CRC校验查表法的设计。基于Xilinx公司ChipScope Pro Analyzer虚拟逻辑分析仪,对其进行在线逻辑分析,验证了设计的可行性,并在实际应用中得以实现,且表现出良好的稳定性和准确性。     

一种并行CRC校验算法的IP设计与实现

CRC是Cyclic Redundancy Check的简称,即:循环冗余校验。传统CRC编码,由于采用移位寄存器进行串行处理,数据吞吐量已无法适应新的速率要求,所以需要采用并行结构CRC编码器。并行CRC的核心思想就是把一个码块中的数据分成多组,每组数据同时进行处理,最终得到本码块的CRC校验序列。     

CRC算法在以太网数据帧中的应用及其硬件实现

文章介绍了CRC校验算法的原理,在串行CRC实现的基础上,对电路结构提出了改进,提出了CRC的并行计算,并基于Verilog HDL语言以CRC8为例说明了硬件电路实现方法。CRC校验广泛应用于数据通信、数据存储领域,结合IEEE802．3标准,说明了CRC算法在以太网帧FCS字段中的应用,并给出了CRC32_D16仿真结果。     

基于FPGA的循环冗余校验实验系统的实现

文章首先分析了循环冗余校验码的功能,在此基础上提出了基于FPGA的实现方法,详细阐述了CRC校验编解码的实现方法,并提出了基于现有的实验箱设备实现小型的CRC校验系统的总体设计框架和设计思路,完成了CRC校验实验系统的设计,充分提高了设备的使用效率.     

基于FPGA的16位CRC校验查表法设计

针对串行通信过程中常用的CRC校验,在Xilinx ISE 10.1中采用IP核建立RAM,用以存入16位CRC校验余式表中的CRC校验码,采用VHDL语言完成了16位CRC校验查表法的设计。基于Xilinx公司ChipScope Pro Analyzer虚拟逻辑分析仪,对其进行在线逻辑分析,验证了设计的可行性,并在实际应用中得以实现,且表现出良好的稳定性和准确性。     

CRC生成与同构逆序校验方法

循环冗余校验码(CRC)被广泛应用于通信领域,CRC生成有两种电路:I型、II型.现有的逆序校验方法是基于II型电路生成、I型电路逆序校验,存在CRC生成与逆序校验电路不同构的问题,不便于模块化设计.根据I、II型电路特性,基于全状态转移矩阵,给出一般情况下,即CRC生成电路寄存器为非零初态时,CRC生成为I型或II型对应的同构I型或II型逆序校验方法.生成与逆序校验同构后,中间处理电路结构不变,参数不同,可以根据需要对其进行优化,提高处理速率.最后,通过实例计算,验证了同构逆序校验方法的正确性.     

短波ARQ通信中的CRC校验算法研究

在对CRC码生成原理进行分析的基础上,针对短波通信中数据串行输出的特点,给出了短波ARQ通信中CRC码的快速校验算法及其编程实现方法。与常用校验算法比较的结果表明,该算法不仅能够充分满足对串行数据CRC校验实时处理的需要,而且思路简单,易于编程实现。     

USB3．0中的CRC校验原理及实现

循环冗余码（CRC）是USB协议中重要的错误检测措施。在此分析了USB3．0数据包的基本格式以及USB3．0协议中CRC校验的特点,针对USB3．0数据高速传输的要求,设计实现并行发送端CRC产生和接收端CRC校验电路,功能仿真结果证明了其有效性。     

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.     

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.     

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.     

避免MOS管在测试时受EOS损坏的方法

由于MOS管是浅结系列产品,极有可能在测试时遭到静电击穿或过压过流而损坏。文中主要介绍MOS管在测试过程中,会造成实际测试时器件加上了允许的最大电压、电流或功率而导致器件损坏的情况。例如,在测试过程中电源连接不良,测试片与器件接触不良,管脚接错,在测试程序中未设置正确的电压和电流钳位或DUT板损坏等。然后,针对此类现象的发生,提出了在测试过程中应采取的相应措施,从而有效地保证产品质量。     

一种改善LED背光亮度均匀性的新型反射膜研究

在LCD的LED背光腔体的底面设计了新型曲面形状及性能的反光膜,将扩散膜反射回灯腔底部的光重新反射回出光口以改善亮度均匀性能;在侧面设计了镜面反射膜,将位于LED矩阵边缘区域由LED射向灯腔侧壁的光反射重新射向出光口,增加了LED背光边缘区域的亮度,从而改善了背光边缘区域较暗的亮度不均匀状况.根据此类反射膜的设计完成了反射膜的制备,并应用于38 cm LED背光源样品.测试结果显示,设置反射膜的LED背光的亮度均匀性值为10.2%,明显优于未设置反射膜的值16.8%,亮度提高了29%左右,表明该种新型反射膜可以提高亮度并改善亮度均匀性.     

Design and nonlinearity compensation of Fabry-Perot type tunable optical filters for dynamic strain sensing systems

The collected spectrum of the fiber Bragg grating （FBG） and the loss of the detected optical power are discussed with respect to the 3-dB bandwidth of a Fabry-Perot （F-P） type tunable optical filter （TOF）, respectively. And the optimized parameters of the TOF are obtained consequently. It is demonstrated that the relationship between the transmission wave- length of the TOF and its drive voltage is nonlinear. A new method to compensate the nonlinearity of the TOF is proposed. The linear sweeping of the transmission wavelength of the TOF is achieved through modifying the drive voltage using interpolation algorithm. It is observed that the average error and the maximum error of the transmission wavelength are reduced sharply under linear fit. The dynamic strain sensing is realized by use of a reference FBG and moving averaging algorithm in this system.     

圆球微腔对水蒸汽的敏感特性仿真实验研究

研究了圆球微腔在水蒸汽传感中应用的可行性。通过测试在有/无水蒸汽的气室环境下,圆球微腔透射光谱的变化来对气室水蒸汽浓度情况进行传感测试。仿真实验结果显示:在有无水蒸汽干扰的条件下系统输出光强有明显的变化,即研制基于圆球微腔的传感器是可行的。     

位屏蔽多叉树搜索射频识别防碰撞算法

针对RFID树型防碰撞算法中时隙数多、数据通行量大等问题,提出了一种改进的多叉树防碰撞算法,阅读器准确检测碰撞位并向标签反馈碰撞位信息,标签对阅读器已知的ID位进行屏蔽,把ID号转换成连续碰撞的序列号.阅读器利用屏蔽位信息和标签返回的碰撞位编码信息,对标签进行分层分类搜索.通过对标签ID进行屏蔽,阅读器和标签间仅发送对方不知道的碰撞位信息.该算法减少了碰撞时隙和识别时隙,避免了空闲时隙,减少了阅读器和标签间的数据通信量.理论分析和仿真结果表明,该算法减少了系统的时隙总数和数据通信量,提高了阅读器的识别效率.     

Analysis of impurity concentration distributions in pulled semiconductor crystals

InSb and GaSb single crystals were grown by the Czochralski method. The impurity concentration distribution in the melt and crystal was investigated experimentally and computationally as a function of the interface segregation coefficient, the shape of the solid-liquid interface and the growth rate. It was found that the impurity concentration distribution in the melt was largely influenced by the interface segregation coefficient; the impurity concentration in the crystal increased as the shape of the solid-liquid interface became more planar and also as the growth rate increased; the impurity concentration was more markedly influenced by the growth rate than by the shape of the solid-liquid interface. When the growth rate was large, the impurity concentration increased and the shape of the solid-liquid interface was concave toward the melt near the crystal periphery. When the growth rate was small, the impurity concentration decreased and the shape of the solid-liquid interface was convex toward the melt.