系统芯片中低功耗测试的几种方法

在系统芯片可测试性设计中考虑功耗优化问题是当前国际上新出现的研究领域。在可测试性设计中考虑功耗的主要原因是数字电路在测试方式下的功耗比系统在正常工作方式下高很多。测试期间的功耗会引发系统成本上升，可靠性降低，成品率下降。本文介绍低功耗测试技术中的一些基本概念，对已有的几种主要的降低测试功耗方法进行分析，最后给出一种高性能微处理器的真速低功耗自测试方法。     

Arsenic/phosphorus LDD optimization by taking advantage ofphosphorus transient enhanced diffusion for high voltage input/outputCMOS devices

Optimization of a LDD doping profile to enhance hot carrier resistance in 3.3 V input/output CMOS devices has been performed by utilizing phosphorus transient enhanced diffusion (TED). Hot carrier effects in hybrid arsenic/phosphorus LDD nMOSFET's with and without TED are characterized comprehensively. Our result shows that the substrate current in a nMOSFET with phosphorus TED can be substantially reduced, as compared to the one without TED. The reason is that the TED effect can yield a more graded n^- LDD doping profile and thus a smaller lateral electric field. Further improvement of hot carrier reliability can be achieved by optimizing arsenic implant energy. Secondary ion mass spectrometry analysis for TED effect and two-dimensional (2-D) device simulation for electric field and current flow distributions have been conducted. The phosphorus TED effects on transistor driving current and off-state leakage current are also investigated     

移动通信网与因特网的桥梁——WAP

本文首先介绍了无线应用协议(WAP)的基本原理、协议结构和技术实现方式 ,然后介绍了WAP的技术发展和应用前景 ,最后简介了中国移动通信的WAP业务开放情况。     

基于HFC的数据广播系统的设计与实现

我们针对缺乏回传通道的传统有线电视网络,设计了一个基于ＨＦＣ的数据广播系统。本文将具体讨论该系统的设计思想。并结合前端和用户端设备,详细描述其软、硬件实现     

MIM隧道发光二极管的电子输运研究

本文报道了MIM隧道二极管的发光和负阻现象,用梯形势垒计算了电流-电压特性。结果显示,由于SPP波对电子的阻挡和束缚作用引起的势垒平均宽度的增加所导致的负阻现象与实验结果相符合。     

改性KTP晶体、三镜折叠腔内倍频研究

本文利用改性ＫＴＰ晶体,进行了纯连续激光倍频实验。根据光束传输矩阵,用计算机数值法计算了三镜折叠腔不同谐振腔参数所对应的稳定区,对Ｎｄ：ＹＡＧ／ＫＴＰ进行腔内倍频,实验获得了３－５Ｗ 纯连续绿色激光输出。其实验结果与理论计算值基本相符。     

多tau光子相关器中自相关函数的归一化方法

提出了采用每个线性相关通道组共享一个监视通道的简化对称归一化方法,并对标准归一化、对称归一化和简化对称归一化的估计偏差进行了理论分析.理论分析表明,对称归一化和简化对称归一化有相近的估计偏差,标准归一化方法的估计偏差较大.采用三种归一化方法,对90 nm,1000 nm及90 nm与1000 nm混合的标准聚苯乙烯乳胶颗粒进行了实验.实验结果表明,标准归一化自相关函数平均估计偏差和最大估计偏差分别是对称归一化和简化对称归一化的2.5～3.5倍和4.5～8.5倍;与对称归一化方法相比,简化对称归一化方法只需增加少量的附加通道资源,即可有效解决在多tau相关结构中存在的大延迟时间的归一化光强自相关函数偏差增大问题.     

MOCVD生长的GaN 薄膜中缺陷团引起的X射线漫散射研究

采用高分辨X射线衍射对在蓝宝石(0001)面生长的GaN外延膜的漫散射进行了研究.结果表明,GaN薄膜中存在缺陷团,其浓度随着穿透位错密度的增加而增加,其平均半径呈相反趋势.基于位错是点缺陷的聚集区,缺陷团优先在位错附近形成的效应对结果进行了解释.同时发现电子迁移率随缺陷团浓度的增加而减少.     

极化干涉合成孔径雷达图像信息提取技术的进展及未来

作为雷达成像遥感一个崭新的研究领域,上世纪90年代末出现的极化干涉合成孔径雷达信息提取技术已日益引起广泛的关注,在未来若干年内必将成为遥感领域的一个趋势和研究热点。该文对目前国内外该技术的进展现状及其应用领域进行了全面的阐述和分析,并在此基础上对该技术的未来发展进行了预测。     

A novel interference suppression scheme for global navigation satellite systems using antenna array

This paper considers interference suppression and multipath mitigation in Global Navigation Satellite Systems (GNSSs). In particular, a self-coherence anti-jamming scheme is introduced which relies on the unique structure of the coarse/acquisition (C/A) code of the satellite signals. Because of the repetition of the C/A-code within each navigation symbol, the satellite signals exhibit strong self-coherence between chip-rate samples separated by integer multiples of the spreading gain. The proposed scheme utilizes this inherent self-coherence property to excise interferers that have different temporal structures from that of the satellite signals. Using a multiantenna navigation receiver, the proposed approach obtains the optimal set of beamforming coefficients by maximizing the cross correlation between the output signal and a reference signal, which is generated from the received data. It is demonstrated that the proposed scheme can provide high gains toward all satellites in the field of view, while suppressing strong interferers. By imposing constraints on the beamformer, the proposed method is also capable of mitigating multipath that enters the receiver from or near the horizon. No knowledge of either the transmitted navigation symbols or the satellite positions is required.