新型城域光纤网络的规划设计

介绍了新型多芯数城域光纤网络，包括光纤骨干环网及接入网络的规划及具体设计，明确了光纤布放芯数及用途，并着重对接入网光纤进行详细分析及设计。     

有线数字电视市县联网光纤环网系统的设计与实践

通过对基于DVB—C1550nm长距离模拟单向光纤传输系统改造为自愈性环网的实践。解决了1550nm光纤环网工程中遇到的接收点主路与备路信号源QAM频点不一致，接收点光功率变化的控制及接收点主路、备路信号切换控制3个主要问题，说明了1550nm光纤环网在有线数字电视市县联网中的广泛应用前景。     

浅析自愈环网构成光纤保护的优点

文中首先对自愈环网光纤保护进行了简要分析,接着就自愈环网构成光纤保护阐述了其规模、优点等方面的内容。     

优化南通电力市县中兴SDH光纤环网系统

本文针对南通电力市县SDH光纤环网系统目前运行的现状,阐述了光纤环网系统有待进一步的改善,并提出了切实可行的结构及配置调整方案。     

大容量光通信系统及其适用的光纤

介绍了大容量光通信系统的商用与科研开发现状，高速率、多信道系统对光纤的性能要求及大容量光纤通信系统所适用的光纤。     

振幅采样结合相位采样的线性啁啾光纤光栅理论与实验研究

为了增加可调谐光纤激光器的调谐带宽,需要一种具有大信道间隔、大的总带宽、各信道的峰值反射率在带内保持均匀而在带外迅速下降的多信道滤波器.提出了一种基于光纤光栅大信道间隔的多信道滤波器实现方法,采用了振幅采样结合相位采样的线性啁啾光纤光栅,基于矩形函数的采样形式,不需要作单个采样的切趾.用所提出方法可以实现一块模板设计任意信道间隔的光纤光栅.通过理论和实验结果的对比,该设计方法得到很好的验证.     

光纤光栅多信道滤波器反射谱的分析

计算了光强均匀分布、高斯分布、升余弦分布下多信道光纤光栅滤波器的反射谱,并分析了模耦合方程中直流耦合分量以及不同光栅参数对光纤光栅多信道滤波器相应谱特性的影响。     

高带宽梯度折射率塑料光纤的数据传输试验

本文首先介绍了高带宽梯度折射率塑料光纤的制造方法和性能;其次阐述了在高带宽梯度折射率塑料光纤上进行的单信道和多信道的数据传输试验.     

光纤旋转连接器

本文简单介绍了光纤旋转连接器的种类、特点、用途。重点叙述了在“单信道多模光纤旋转连接器”研制过程中遇到的技术问题和研究结果。为在双信道、多信道器件预研中提供一些参考经验。     

OFDM-ROF下行链路的性能研究

OFDM技术与ROF技术结合为实现低成本、高速数据传输的移动网络提供了可能,但光纤链路的非线性以及无线信道的多径衰落降低了系统性能。在建立ROF下行链路的传输函数模型基础上,分析ROF下行链路对OFDM信号性能的影响。传输模型包括激光器,光纤链路以及无线信道。分析在不同光调制指数、光纤长度及无线多径信道下接收信号的误差矢量、三阶非线性失真和互调失真。仿真结果显示：随着调制指数、光纤长度的增加,以及无线信道的多径衰落使得接收信号性能下降。此分析为OFDM-ROF下行链路的线性化以及无线信道均衡方案选择提供了理论基础。     

信源数目过估计和欠估计下MUSIC算法分析

分析了信源数目过估计与欠估计情况下的MUSIC算法性能，仿真实验发现信源数目过估计下MUSIC谱出现伪峰，并且随着过估计程度的加重伪峰的数目增多，DOA估计的均方根误差增大；而欠估计情况下某些谱峰消失，并且随着欠估计程度的加重谱峰数减少，均方根误差增大。提出一种改进算法，在信源数目有误差的情况下，该算法的性能好于MUSIC算法的性能。     

PCFICH配置对用户终端吞吐率影响研究

在LTE系统中,PCFICH信道配置主要作用是指示PDCCH控制信道在一个子帧内占用OFDM符号的个数,PDCCH控制信道数量直接影响小区可调度用户数和峰值速率.为了找出不同场景下最优的PCFICH信道配置,以达到最高的用户终端吞吐率,本文通过计算不同PCFICH配置数下的理论峰值速率,对用户数分段进行试验,并结合实际...     

基于椭圆曲线数字签名算法的序列号软件保护方案

结合身份的认证,提出了一种基于椭圆曲线数字签名算法的序列号保护方案,该方案包括序列号的生成和验证两部分。软件代理商利用序列号生成方案生成序列号,并利用加壳机制将序列号验证部分嵌入到软件中,用户输入的序列号经过验证后才能安装该软件。由于序列号的安全性寓于私钥而不是算法本身的安全性,只要私钥不被泄漏,破解者无法根据序列号和公钥生成新的序列号。因此,该方案具有很好的安全性和有效性。     

移动用户号码携带对我国码号资源管理的影响

电信网中的用户号码资源和运营企业之间有着一定的对应关系,不同号段的号码归属于不同的运营商。移动号码携带业务的提供,剥离了号码和运营商之间的对应关系,这对原有码号管理和各类码号应用都产生了一定的影响。本文结合我国当前对码号的管理规定和政策,分析了移动用户号码携带对我国码号管理以及管制政策可能带来的影响。     

A study on energy optimized 4 dot 2 electron two dimensional quantum dot cellular automata logical reversible flip-flops

In the present scope, new design methodologies for reversible flip flops are proposed and the results are analyzed by the QCADesigner tool. To the best of our knowledge such methodologies are reported for the first time in the literature. In this paper, we provide few formalisms also. The first one is for the system energy derived using Hamiltonian paradigm and provides internal energy of cell electrons. The second formalism provides the minimum energy requirement for execution of a QCA architecture. This procedure reduces wastage of clock energy. Two very interesting parameters are identified playing crucial role in this context: (i) The electron quantum number n which indicates quantum energy level and (ii) intermediate quantum number for an electron lying between 1 and (n−1). It is established that the incident energy frequency is directly proportional to the number of cells and quadratic function of electron quantum number and intermediate quantum number. The dissipated energy frequency is also directly proportional to the product of number of cells and quadratic function of electron quantum number. This paper, reports some remarkable results. The relaxation time is observed being inversely proportional to the product of number of cells in the architecture and quadratic function of quantum number as well as intermediate quantum number. Apart from these, differential frequency is found directly proportional to the number of cells in the architecture and quadratic function of intermediate quantum number. Few major observations are also indicated: (i) There is always a probability of reflection even if the system energy exceeds barrier energy. (ii) On the contrary, there is always a probability of transmission even though system energy is dominated by the barrier energy.     

Efficiency of the GSM-GPRS Air Interface for Real-Time IP Traffic Flows With and Without Packet Dropping

One IP terminal can occupy a single slot or a multiple number of slots within time frames in the GSM and GPRS, respectively. A limited number of radio resources (slots) are allocated in a base station for such IP terminals. If one IP terminal can occupy only one slot discontinuously in a time frame, there is one possibility resorting to all IP terminals to preserve active mode at a time. Thus, the number of accepted call in the GSM is the same as that of the radio resource. Similarly, if one terminal can occupy a multiple number of slots discontinuously/dynamically in a time frame, the number of accepted calls is obtained by dividing the number of radio resources during that time by the maximum allowed number of slots per IP terminal. A burstiness factor is defined for the IP traffic over GSM-GPRS air interface. Traffic channel efficiency with a bursty real-time IP traffic is unacceptably low, especially with the range of acceptable call loss probabilities pertaining to a lower burstiness factor. The channel efficiency can be enhanced and the call loss probability can be suppressed significantly if a higher maximum number of calls is accepted. Allocated radio resources are less than the maximum number of packet transmissions at a time. Therefore, some packets could be dropped from the real-time transmission system. A complete analysis for the real-time IP packet transmission over the single slot GSM and dynamically variable multislot GPRS air interface without packet dropping, and with packet dropping that increases the channel efficiency is executed. Results show that the channel efficiency as well as the packet dropping probability increases with increasing call intensity, maximum number of admitted IP calls and the burstiness factor.     

用PB和ORACLE方法实现身份证号升位

在对人员的管理工作中 ,需经常使用姓名和身份证号来进行人员检索。身份证号所具有的唯一性 ,决定了它成为表征一个人信息的准确特征。原有的 15位身份证号存在着“2 0 0 0年”问题 ,需升至 18位。本文分别用PB和ORACLE两种语言方式 ,讲述了实现身份证号升位的方法。     

A chip-based multiuser detector for the downlink of a DS-CDMAsystem using a folded state-transition trellis

The maximum-likelihood sequence estimation (MLSE) multiuser detector has very good performance but at the expense of high computational complexity. The Viterbi algorithm is employed to implement the MLSE in the asynchronous uplink. In this scheme, the various bit-combinations are taken to be the different states in the decoding trellis. However, the number of states increases exponentially with the number of active users. We propose a scheme that exploits the feature of power-equality in the downlink to reduce the number of states involved. Each transmitted chip value can only take a certain number of possible discrete values. Using these discrete values as the states in the transition trellis diagram and operating the Viterbi algorithm at the chip level, the number of states is reduced from 4^K to (K+1) ^L where K is the number of users and L is the number of paths in the multipath channel     

一维光子晶体偏振滤波器通道数的影响因素研究

光子晶体偏振滤波器是利用光子晶体带隙特性来控制信号光偏振状态的一种新型滤波器, 在光纤通信、光学传感测量、光学信息处理等领域均有重要应用。通道数多少是偏振滤波器设计的重要指标, 通道越多则信息容量越大, 越有利于系统的小型化微型化。利用光学传输矩阵法研究了影响一维光子晶体偏振滤波器通道数目的因素, 研究表明：(1）光子晶体缺陷层厚度是影响滤波器通道数目的关键因素, 通道数N与厚度D近似满足线性关系, 在500 ～650 nm波段函数关系为N=0.0035D+0.159; (2）缺陷层折射率nc的变化也会导致通道数改变, 折射率越大通道数越多;( 3）光子晶体单元层数和单元厚度改变不会影响滤波通道数, 但可以调节通道中心波长位置, 同时对偏振度和分离度也有影响。     

纸币号码识别技术研究

研究了纸币号码识别技术.针对水平冠字号和垂直冠字号的特点,分别对号码数字图像进行了预处理、去噪、分割等处理,然后利用区域模板矩阵作为特征参数,进行模板匹配实现号码识别,并对一些易混淆的字符进行特殊区域信息比较.在实践中水平冠字号的识别率达98%,垂直冠字号的识别率达93%.