固移无线网络融合实现技术浅析

FMC是当前运营商应对市场竞争的有效手段,是电信网络未来的发展方向,也是备受业界关注的热点话题。本文介绍了业内普遍认可的两种FMC实现方式UMA(Unlicensed Mobile Access,非授权移动接入)和IMS(IP Multimedia Subsystem,IP多媒体子系统),特别提到了SIP(Session Initiation Protocol,初始会话协议)信令协议,对每种实现方式架构、原理、优缺点进行探讨,并总结了FMC实现方式未来的技术发展趋势。     

激光二极管端泵平板Nd:GdVO4晶体热效应

以解析热分析理论为基础,建立了平板Nd:GdVO<,4>激光晶体在激光二极管阵列端面抽运时的导热微分方程.通过对方程的求解,得到了Nd:GdVO<,4>晶体内部温度场解析式和热透镜焦距随抽运光半径和功率变化的分布关系.温度场的数值模拟表明:当泵浦光功率P=30W、泵浦区域为1 mm×1 mm时,晶体在x,y,z方向的最...     

拉曼-纳斯衍射声光Q开关的实验研究

实验研究了拉曼-纳斯(R-N)衍射的声光相瓦作用长度与声波光波参数之间的关系,确定了最佳声光相互作用长度.在此基础上,分别设计以水和TeO2晶体为声光介质的R-N衍射Q开关器件,测量了器件的衍射效率、衍射角和插入损耗等参数.应用TeO2晶体开关器件调制长脉冲Nd:YAG/KTP激光器,当重复频率为10 kHz时得到了脉...     

定长光突发交换节点的QoS性能分析

分析了光突发交换网络中基于附加偏移时间(EOT,extra offset time)的业务优先等级区分服务的变长突发方案的不足，提出了一种定长光突发方案。它能在较小附加延迟的情况下保证高优先级的业务完全不受低优先级业务的阻塞，即使每个优先级的附加等待时间都减小到变长突发方案的1/3，同时使最高优先级业务的阻塞率更小，而且具有现实可行性。     

像面位置可调定焦距标星电视系统结构设计

为了标定试验设备空间位置,研制了一种像面位置可调的定焦距标星电视系统.星光经主镜和次镜反射后通过透镜组聚焦,成像在CCD靶面上;采用直线位移平台改变CCD靶面沿光轴方向的位置,直线位移误差不大于0.002 mm,解决了由于温度变形使星像偏离CCD靶面产生成像不清晰的问题.通过可见光探测标星试验验证,定焦距标星电视系统的...     

基于低码率线性分组码的分组交织长度识别

交织长度的识别是交织器识别过程中重要的步骤,关系到纠错码识别和信息的获取,具有重要的研究价值。文中简要介绍矩阵分析法,针对矩阵分析法容错能力不强的缺点,借助码重分布的概念,提出利用块重分布识别低码率二进制线性分组码序列交织长度的方法。最后,对两种方法进行仿真对比,分析了各自的适用范围和容错能力。     

Investigation of geometry dependence on MOSFET linearity in the impact ionization region using Volterra series

In this paper, investigation of device geometry on intermodulation distortion (IMD) of metal–oxide–semiconductor field-effect transistors (MOSFETs) is presented in the impact ionization region based on the Volterra analysis. As the gate length or gate width decreases, observed linearity improvement of the MOSFET in the breakdown regime is attributed to the more obvious breakdown inductance nonlinearity which cancels the transconductance nonlinearity. Linearity of the MOSFETs can be improved by choosing suitable device geometry in the breakdown region. It is believed the presented analysis results can benefit the reliability investigation for MOSFET linearity in the breakdown region.     

Channel length influenced contribution of hole and electron trapping effect to threshold voltage stability in organic field effect transistors

Effect of channel length on hysteresis and threshold voltage shift in copper phthalocyanine (CuPc) based organic field effect transistors was studied. Contrary to expectation, longer channel length devices exhibited minimum threshold voltage shift. Influence of channel length on the contribution of hole and electron trapping to threshold voltage stability was determined. Shortest channel length devices exhibited highest electron trapping effect while longest channel devices exhibited minimum hole as well as electron trapping. Lower hole trap effect for longer channel length devices was suggested to be due to reduced longitudinal field between source and drain electrodes while minimum electron trapping was attributed to suppression of drain current by increased hole trap centres.     

Minimal cost one-dimensional linear hybrid cellular automata of degree through 500

This letter is a supplement of the table of the minimal cost one-dimensional linear hybrid cellular automata with the maximum length cycle by Zhang, Miller, and Muzio [IEE Electronics Letters, 27(18):1625–1627, August 1991].This work was supported in part by Research Grants and Postgraduate Scholarships from the Natural Sciences and Engineering Research Council of Canada and by an equipment loan from the Canadian Microelectronics Corporation.     

长约束度卷积码译码器神经网络结构

给出的神经网络译码器是为长约束度（Ｋ≥１１）卷积码译码而设计的。Ｖｉｔｅｒｂｉ译码和序列译码是两种最大似然译码方法,虽然这两种技术能有效地提高误比特率性能,但它们都丰在局限性。另外,只要在神经元和数字异或门单元之间建立局部连接,就能非常容易地直接超大规模集成电路（ＶＬＳＩ）实现硬件。