采用协处理器解决方案的TD-SCDMA手机

在ＴＤ -ＳＣＤＭＡ网络建设的初期 ,对ＴＤ -ＳＣＤＭＡ终端的基本要求是它必须是ＧＳＭ／ＴＤ -ＳＣＤＭＡ双模的。ＲＴＸ的解决方案将ＴＤ -ＳＣＤＭＡ的功能模块加入到ＧＳＭ基带芯片集里。通过使用到ＴＤ -ＳＣＤＭＡ协处理器的通用接口 ,有可能将协处理器集成到任何一个现存的ＧＳＭ基带芯片集和终端设计中。从硬件的的角度看 ,协处理器包括 :ＴＤ -ＳＣＤＭＡ基带编解码和ＴＤ -ＳＣＤＭＡ射频 ;ＴＤ -ＳＣＤＭＡ信号处理器 ;ＴＤ -ＳＣＤＭＡ基带模块。为了能够获得一个商用产品 ,ＲＴＸ也考虑到相应的开发环境和工具。其第一（物理…     

热成像温差分辨率与微分光谱匹配因数的关系

由近距离低温面目标热成像系统的信号方程和噪声等效温差ＮＥＴＤ的定义，导出了ＮＥＴＤｏｃ１／Ｍ，并由此得到ＭＲＴＤｏｃ１／Ｍ，ＭＤＴＤｏｃ１／Ｍ，从而证明了热成像系统的温差分辨率；ＮＥＴＤ、ＭＲＴＤ、ＭＤＴＤ均要求微发光谱匹配因数Ｍ要大，这为选用光谱区配因数Ｍ和Ｍ作为热成像系统的综合评价参数奠定了理论基础。     

通用性和经济性于一体的TDS1000／2000系列数字存储示波器

ＴＤＳ１０００和ＴＤＳ２０００系列数字存储示波器集强大的功能、通用性和经济性于一体,以实时性能帮助您快而准地完成各项测试和测量工作。对设计师和技术人员而言,ＴＤＳ１０００和ＴＤＳ２０００系列以其高带宽、取样速率、高级触发、彩色显示屏     

光时分复用技术

时分复用（ＯＴＤＭ）技术是实现超高速传输的很有交的技术。本文论述了ＯＴＤＭ的主要技术及其前景，通过对ＯＴＤＭ技术在点对点通信系统对网络系统中的应用介绍，提出了ＯＴＤＭ和ＷＤＭ的结合是将来网络发展的方向。     

要闻

ＴＤ -ＳＣＤＭＡ首次通话４月１１日 ,世界瞩目的全球ＴＤ -ＳＣＤＭＡ系统首次开通演示在京进行 ,表明自主开发的ＴＤ -ＳＣＤ ＭＡ系统商用迈出了成功的一步。这次由大唐集团中央研究院和西门子信息与移动通讯集团合作进行的首次系统间通话演示 ,是在两台通过ＴＤ -ＳＣＤＭＡ基站和测试终端设备、以无线通信方式连接的ＰＣ机上进行的。据介绍 ,目前ＴＤ -ＳＣＤＭＡ产品的软硬件开发工作已基本完成 ,随着系统集成与实验的进一步深入 ,ＴＤ -ＳＣＤＭＡ系统将陆续实现数据、多媒体图像等高速数据传输功能。ＴＤ -ＳＣＤＭＡ最大的优点在…     

信息产业部公开第三代移动通信标准

近日 ,信息产业部科技司在北京主持召开专门会议 ,由信息产业部电信科学技术研究院公开第三代移动通信ＴＤ—ＳＣＤＭＡ标准部分技术 ,包括ＴＤ—ＳＣＤＭＡ标准的组成和基本思路、ＴＤ—ＳＣＤＭＡ无线系统的基本设计原理、智能天线、联合检测技术的算法以及用此算法的仿真结果。信息产业部电信科学技术研究院作为ＴＤ—ＳＣＤＭＡ技术标准的主要提出者 ,拥有ＴＤ—ＳＣＤＭＡ相关专利并掌握核心技术 ,通过本次公开ＴＤ—ＳＣＤＭＡ部分技术 ,旨在使国内的运营商、制造商能够更加深入地了解ＴＤ—ＳＣＤＭＡ的技术优势 ,从而在政府相关部门…     

简述我国的TDMA网

简述我国的ＴＤＭＡ网陈肇基为了满足我国中心城市间数字通信迅速增长的需要．邮电部于１９９０年建成了ＴＤＭＡ（时分多址）网，首期开通了北京、广州、乌鲁木齐ＴＤＭＡ电路．１９９３年又开通了上海的ＴＤＭＡ电路。我国邮电部的ＴＤ．ＭＡ网络如图；所示。ＴＤＭＡ网...     

论坛指南

ＴＤ－ＳＣＤＭＡ技术论坛 ＴＤ－ＳＣＤＭＡ技术论坛由中国移动通信集团、中国联合通信有限公司、中国电信集团公司、华为技术有限公司、摩托罗拉公司、北电网络公司、大唐电信科技产业集团和西门子公司联合发起,论坛成立大会将于今年１１月下旬在北京举行。论坛的宗旨是宣传ＴＤ－ＳＣＤＭＡ技术,促进ＴＤ－ＳＣＤＭＡ技术的进步和完善,积极促进 ３ＧＰＰ／ ＴＤＤ的融合,推动未来３ＧＰＰ 融合后的ＴＤＤ技术规范在全球范围内广泛应用。论坛将为全球范围内的运营商、设备制造商、研究机构、教育机构、标准化组织以及其它相关公司或团…     

光时域反射仪选购中应注意的问题

光时域反射仪（ＯＴＤＲ）是光纤通信中常用仪表之一。近几年，ＯＴＤＲ生产厂家越来越多，功能也有较大差异。如何从诸多厂家的不同型号、不同技术指标的ＯＴＤＲ中选购自己所需的仪表，是工程技术人员较困域的问题。现地ＯＴＤＲ的部分技术指标做一简单介绍和分析，以便人们在选购ＯＴＤＲ时，均衡考虑各项指标，购置合适的仪表。     

超高速OTDM进展及Tbit/s级可行性分析

介绍了高速光时分复用（ＯＴＤＭ）的关键技术,总结了ＯＴＤＭ光传输的最新进展,对实现Ｔｂｉｔ／ｓ　ＯＴＤＭ光纤 通信的可行性和关键技术做了分析。     

语音时域分割研究

在语音时域挑选剩余可懂度低的可用置换集合,置换集合是语音TDS系统中不可缺少的重要环节,本文给出了可用置换选取的条件、客观评价标准和方法。     

宽带光交换技术

光交换是一种宽带交换技术。本文简述了空分、时分、波分、码分光交换技术的原理、结构、特点，并阐述了目前光交换技术的发展水平和研究进展。     

快速高精度全数字锁相环研究

为解决全数字锁相环快速捕获和过滤噪声之间的矛盾,本文提出了一种应用于位同步的具有自动变阶特性的快速高精度超前/滞后全数字销相环(从-DPLL),文中介绍了新的设计思想,重点进行了理论分析,最后给出了有关实验结果。     

时分双工方式下的F-PRMA协议及其性能分析

本文提出了一个适合微蜂窝移动通信的时分双工方式下的分组预约多址协议－Ｆ－ＰＲＭＡ（Ｆｒａｍｅ－ｂａｓｅｄＰａｃｋｅｔＲｅｓｅｒｖａｉｔｏｎＭｕｌｔｉｐｌｅＡｃｃｅｓｓ）利用马尔夫过程理论为Ｆ－ＰＲＭＡ协议系统建立了三状态简化模型，应用Ｔａｓａｋａ提出的平衡点分析方法（ＥＰＡ）对该协议进行了性能分析，推导出分组丢弃概率和系统吞吐率等重要性能参数的解析式，通过数值分析和系统仿真全面考察了允许概率Ｐ帧长     

CCD时序与基于时分复用的实时数据处理系统设计

分析并设计了e2v公司的CCD42-80 Back Illuminated AIMO型CCD器件驱动时序,完成了一种既节省硬件资源,又能实时、准确输出图像数据的CCD数据处理系统.采用了曝光时间可调节设计来适应相机观测目标的多变性,使用时分复用技术结合乒乓操作、后进先出(LiFo)等技术,保证了图像的质量和实时性.应用一片可编程门阵列FPGA作为硬件设计载体,使用Verilog-HDL硬件描述语言并采用自上而下的模块化设计对整个系统进行硬件描述.在系统时钟64 MHz、图像输出速率200 kHz条件下,测试结果表明,时序电路工作正常,可以满足CCD相机的驱动要求,相机系统输出的图像实时、稳定.基本满足了观测系统对CCD相机在成像和数据传输方面的要求.     

A GMSK Receiver with Beamformer Weight Refinement

We present an adaptive antenna algorithm for Gaussian minimum-shift keying (GMSK)-based cellular systems with beamformer weights that are iteratively computed using re-encoded data to suppress cochannel interference (CCI). Filtered training sequences are proposed in order to compensate for the effects of timing offsets that occur for asynchronous cochannel signals. Also, we extend the receiver to include a linear equalizer that mitigates intersymbol interference (ISI). Various multistage receivers incorporating the proposed beamformer and equalizer algorithms are presented. Their performance is evaluated using simulated and real time-division multiple-access (TDMA) data, demonstrating that the proposed beamforming algorithms suppress CCI and significantly improve the performance compared to a conventional GMSK receiver.

Novel Distributed Fiber Bragg Grating Sensing System Based on M-Z Interferometer

One of the problems in using grating sensors is how to measure a small Bragg wavelength shift accurately. Nowadays demodulation techniques are mainly based on the edge filter, tunable filter, or interferometric scanning methods. Interferometric demodulation is widely accepted as the technology which can provide the high sensitivity. An interrogation system using the interferometric scanning method is presented, in which an unbalanced fiber M-Z interferometer is used as the wavelength scanner for temperature measurement. A novel fiber Bragg grating sensor system based on M-Z interferometric demodulation technique is presented in this paper. The temperature sensitivity measured in the experiment is almost consistent with that obtained from the theoretic calculation.     

Frequency synchronization for TD-LTE-A downlink receiver

A high accuracy frequency synchronization method is proposed for the 3rd generation partnership project (3GPP) long term evolution advanced (LTE-A) downlink receiver in time division duplexing (TDD) mo...     

Time Agility Optimization for Dual-stage Collaborative Spectrum Sensing

Cooperative spectrum sensing has been shown to be an effective method to mitigate the impact of hidden terminal and shadow fading in cognitive radio networks. Currently most works focused on either coop- erative sensing or sensing scheduling as a viable means to improve the detection performance without studying their interactions. This paper proposed a dynamic and variable time-division multiple-access scheduling mechanism that was incorporated into a Dual-stage collaborative spectrum sensing （DCSS） model in a less ideal radio environment. Moreover, this paper derived closed-form expressions of sensing time for DCSS, and addressed the critical range of timeslot length. An optimized algorithm to minimize sens- ing time was deduced and verified. The simulation results indicate that average sensing time with DCSS is shortened by 11.5~V0 when compared with that of the Single collabora- tive spectrum sensing （SCSS） while guaranteeing detection error rate requirement of less than 1%.     

Interfacial reaction and shear strength of SnAgCu-xNi/Ni solder joints during aging at 150 °C

The interfacial microstructure and shear strength of Sn3.8Ag0.7Cu-xNi (SAC-xNi, x = 0.5, 1, and 2) composite solders on Ni/Au finished Cu pads were investigated in detail after aging at 150 °C for up to 1000 h. The interfacial characteristics of composite solder joints were affected significantly by the weight percentages of added Ni micro-particles and aging time. After aging for 200 h, the solder joints of SAC, SAC-0.5Ni and -1Ni presented duplex intermetallic compound (IMC) layers regardless of the initial interfacial structure on as-reflowed joints, whose upper and lower IMC layers were comprised of (CuNi)₆Sn₅ and (NiCu)₃Sn₄, respectively. Only a single (NiCu)₃Sn₄ IMC layer was ever observed at the SAC-2Ni/Ni interface on whole aging process. Based on the compositional analysis, the amount of Ni within the IMC regions increased as the proportion of Ni addition increased. The IMC (NiCu)₃Sn₄ layer thickness on the interface of SAC and SAC-0.5Ni grew more slowly when compared to that of SAC-1Ni and -2Ni, while for the (CuNi)₆Sn₅ layer the reverse is true. Except the IMCs sizes are increased with increased aging time, the interfacial IMCs tended to transfer their morphologies to polyhedra. In all composite joints testing, the shear strengths were approximately equal to non-composite joints. The fracturing observed during shear testing of composite joints occurred in the bulk solder, indicating that the SAC-xNi/Ni solder joints had a desirable joint reliability.