基于流水线CORDIC算法的数控振荡器

数控振荡器(NCO)的实现通常都是基于查表的方法,为了达到高精度要求,常常需要耗费大量的ROM资源去建立庞大的查找表。提出了一种基于坐标旋转算法(Coordinate Rotation Digital Compute,CORDIC)的流水线型数控振荡器的实现方法。硬件描述语言的仿真与综合结果表明,采用这种方法设计的数控振荡器精度高、误差小、结构简单,与基于查找表的数控振荡器相比,更易于ASIC实现,最后给出了该方案的仿真结果。     

基于CORDIC算法的数控振荡器的FPGA设计

数控振荡器在数字信号处理中有着广泛的应用。本文研究并实现了基于CORDIC算法的流水线型数控振荡器。仿真和验证结果表明,该方法较之查找表法精度高,且结构简单、耗费资源少,非常易于FPGA实现。     

软件无线电系统中NCO的设计与实现

介绍了软件无线电系统中基于FPGA的数控振荡器(NCO)的实现方法，详细讨论了查找表和CORDIC算法的原理。通过软件仿真和测试，所设计的数控振荡器可以根据系统输出精度和硬件资源的不同，通过选择不同算法和参数来满足系统设计的要求。     

基于Taylor级数近似补偿的改进数控振荡器实现

本文通过对传统CORDIC算法实现数控振荡器存在的问题进行分析,提出一种适用于软件无线电通信系统的数控振荡器改进实现方法:采用流水线结构采实现数控振荡器,可满足高速数据处理的需求;用二阶泰勒(Taylor)级数近似、残余相角补偿等措施来补偿传统CORDIC算法实现在精度方面的不足;设计引入的抖动模块改善角度周期性截断误差所引起的杂散,进一步提高了数控振荡器的精度.     

基于FPGA和SRAM的数控振荡器的设计与实现

介绍数控振荡器的工作原理,重点阐述用现场可编程门阵列(FPGA)和静态随机存储器(SRAM)实现数控振荡器的方法,同时给出采用此结构设计的数控振荡器的特点和性能.     

基于CORDIC算法的数字下变频技术设计与实现

传统的基于查表法的数控振荡器耗费大量的FPGA片内资源。为了解决这一问题，提出了一种基于CORDIC（coordinate rotation digital compute，坐标旋转数值计算）算法的数控振荡器的设计方法，而且该算法使数控本振和数字混频两个功能合在一起完成，省去了两个乘法器。最后通过仿真证明了其有效性，具有较高的工程应用价值。     

数字控制振荡器（NCO）的FPGA实现

介绍了NCO数字控制振荡器的工作原理,详细分析了数控振荡器的性能指标和其在FPGA中的实现方法,最后给出了新设计的数控振荡器在QUARTUSII中的仿真结果。     

基于DSP的数字式多路正弦波发生器设计

详细论述了数控振荡器的工作原理,介绍了使用DSP实现数控振荡器的功能和产生多路正弦波的方法。该方法基于DSP中断,以中断发生的频率代替数控振荡器的相位累加时钟频率,采用多个相位累加器,在中断服务程序中多次查表输出正弦值,以产生多路正弦波。文中给出了源代码,并分析了在使用DSP产生正弦波时需要设置的一些参数,以及这些参数如何影响该系统的工作情况。     

基于查找表和CORDIC算法的数控振荡器的设计

研究了一种基于查找表和CORDIC (Coordinate Rotation Digital Computer)算法相结合的数控振荡器(NCO)的实现方法,与仅基于查找表的方法相比,该方法结构简单、精度高、耗费资源少.仿真和验证结果表明,该设计是可行的,并易于FPGA实现.     

基于FPGA的正交数字混频器中数控振荡器的设计与实现

本文介绍了一种利用矢量旋转CORDIC(COordination Rotation Digital Computer）算法实现正交数字混频器中的数控振荡器(NCO)的方法。首先推导了CORDIC算法产生正／余弦信号的实现过程，然后给出了在FPGA中设计数控振荡器的顶层电路结构，并根据算法特点在设计中引入流水线结构设计。     

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.     

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