SDH光缆网络保护机构(I)

介绍了光缆通信网络可靠性与有效性的基本概念及为提高可靠性采用的标准保护网络，对保护网络的核心问题—网络主备保护切换功能、技术参数、保护信道协议以及性能参数的测量方法等等进行了重点论述。指出，由于ＳＤＨ体系结构的不同，决定了主备保护切换系统有统一的标准，与ＰＤＨ系统相比，不但可靠性高，而且因信道的冗余，为网络的智能化创造了条件。     

1:1方式带备纤监控的光路检测系统研制

1:1方式带备纤监控的光路检测系统采用ARM核的32位低功耗微处理器作为系统控制核心,系统采用嵌入式μCOS-II2操作系统,可实现主备光纤信道状态同时检测,发现故障时瞬时切换到备用信道,切换时间小于15ms,大大低于ITU-TG.841标准所规定的50ms,确保光路通信畅通无阻,具有实时性强、动态性能良好,运行稳定可...     

一种实现堆叠网络交换机快速切换控制的方法

随着测控通信技术和计算机网络技术的发展,卫星地面站都不同程度地使用千兆网核心交换机建立系统监控及业务数据网络传输,实现了测控终端设备的无人值守和远程监控,设备控制的可靠性与稳定性大大提高。但是,当主用交换机出现故障时,即使备用交换机是堆叠放置且处于热备份,交换机网络端口的物理通路仍需人工进行插拔完成切换操作,当交换机网络端口数量较多时,人工切换操作时间较长,时效性不高,在任务用时占用比例较大,制约了卫星地面站系统的应用效率。针对以上问题,提出了一种采用继电器机电设备实现主备交换机网络端口的物理切换控制方法,进行了网络切换器的设计和可靠性分析,给出了应用实例。实验测试结果表明,这种物理切换控制方法使得主备交换机网络端口的切换效率提高百倍。     

嵌入式系统主备电源的自动切换方法与实现

本文介绍了嵌入式系统主备电源自动切换的两种方法,对电压不相等的主备电源系统进行自动切换,具有功耗低,成本低,可靠性高等特点。文中给出了一种由 5V 电源适配器作为主电源供电、9V 电池作为备用电源的主备电源自动切换的具体实现电路,该电路在实际应用中得到了良好的效果。     

给SDH设备加装保护系统

传输网络的安全可靠运行是为用户提供优质服务的基础。由于种种原因 ,我国一级干线的ＳＤＨ传输网基本采用链状结构 ,系统的安全性得不到有效保障 ,当系统发生阻断时不仅会给用户带来巨大经济损失 ,而且会严重影响企业形象。近年来 ,国内先后有多条ＤＷＤＭ干线投入运行 ,如果能利用ＤＷＤＭ系统中的空余资源来给重要的ＳＤＨ系统设置保护系统 ,不仅可以充分利用空余资源 ,还可大大提高ＳＤＨ系统运行的可靠性和稳定性。西门子、爱立信的ＳＤＨ系统已在国内长途干线网上大量使用 ,基本未作保护 ,本文介绍了用朗讯、北电ＤＷＤＭ的相关信道构…     

网管软件主备切换协议的设计和验证

软件系统的主备切换功能可以保证系统的高可靠性。该文设计了一种简单的主备切换协议,提供了主备切换协议中的帧设计,描述了该协议在启动监控和执行监控切换时的状态,以及自动切换和手动切换的情况。并将这一功能应用于网络管理软件,有效降低了丢包率,提高了系统的可靠性。最后对该协议进行了验证。     

电源切换对系统工作影响分析与解决方案

为提高系统工作可靠性,尤其是系统供电的可靠性,经常需要提供两路稳定可靠性的工作电源,在一路电源出现故障时可以迅速切换到备路电源,但是切换电路的设计需要和系统进行适当的匹配设计,否则在电源主备路切换继电器在进行切换时,有可能导致系统工作异常,本文对故障产生原因进行了分析,对切换电路提出了优化改进方案,并通过试验验证了优化方案的正确性和可行性。     

中波天线主备调配网络切换系统设计

为了防止中波调配网络因故障而无法正常播出,系统设计了一款中波天线调配网络主备切换系统。利用该系统,值班人员可对主备调配网络进行手动切换,有效保障了广播电视的安全播出,可辅助从事广播电视播出工作的人员更好地完成相关工作。     

降低摩托罗拉GSM系统中SDCCH拥塞的方法

移动通信用户的迅猛增长对ＧＳＭ网络的运行提出了更高的要求。摆在ＧＳＭ系统工程师面前的首要任务就是在保持现有网络的稳定性、可靠性的同时,不断提高ＧＳＭ网络的各项运行指标。本文对摩托罗拉ＧＳＭ网络中独立专用控制信道（ＳＤＣＣＨ）进行了介绍,着重分析了解决ＳＤＣＣＨ拥塞的若干常见方法,希望能给同行们提供参考。     

OFDM与数字HDTV的单频网广播

介绍地面数字ＨＤＴＶ的单频网广播技术，并与单载波主发射机方案进行比较，提出ＯＦＤＭ系统中的一种信道估值新方案，它能显著地改善ＯＦＤＭ系统的频谱利用率。数字ＨＤＴＶ的单频网广播被长时延多径干扰所困扰，给出了克服长时延多径干扰的一种方法。     

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.