集成电源噪声抑制的时钟源简化FPGA系统的电源设计

本文对高性能应用的FPGA设计中的电源噪声情况进行了说明,并由此指出FPGA设计对时钟源的特殊要求,进而对目前通用的小数分频式晶体振荡器(XO)结构以Silicon Labs DSPLL XO/VCXO结构进行了分析和对比.     

基于迫零检测的分布式发射天线V-BLAST OFDM系统中的载波频偏补偿

 在采用分布式发射天线的垂直贝尔实验室分层空时结构(V-BLAST)正交频分复用(OFDM)系统中,由于各发射天线与接收机之间的载波频偏(CFO)均可能不同,传统系统中针对单个频偏的简单补偿方法不再适用。不同于已有的使用高复杂度矩阵求逆运算的线性频域均衡方法,本文利用迫零(ZF)检测的固有特性,提出一种适用于低时延扩展多径信道的无需矩阵求逆运算的载波频偏补偿方法。仿真结果表明,在ITU-R M.1225信道模型的三种低时延扩展测试环境下,使用本文所提频偏补偿方法进行频偏补偿能有效改善系统误符号率(SER)性能。     

高集成度可编程车载收音机接收方案

全球金融风暴正在对汽车产业造成深刻影响,不论是出于成本考虑还是环境保护和燃料效率等,在以美、欧、日本为主的汽车市场,越来越多     

风河诠释其三大基础技术优势

前不久,风河(Wind River)在国内重要城市举办的2010开发者区域大会,仍延续前三年的多核与虚拟化主题,不仅技术应用更为广泛,而且以其在网络与通信、航空航天与国防以及工业控制等应用领域的丰硕成果向与会者展现了多核技术为各个应用领域注入的创新动力。     

新的V-BLAST系统次优天线选择

该文提出新的基于ZF SIC检测的V-BLAST系统次优天线选择准则:最小化信道矩阵伪逆的最大行范数。基于贪婪选择思想,发射天线选择采用使得该范数增加最小的递增选择策略,接收天线选择采用使得该范数减少最大的递减选择策略。仿真表明所提出的新准则明显优于已有的最大第1检测层后处理信噪比准则,且相应的快速选择算法可以获得最优的基于最大最小准则的全搜索选择的大部分分集增益,而复杂度很低。     

贝尔实验室丰硕的诺贝尔奖成果及其启示——纪念贝尔实验室成立75周年

将美国的工业实验研究分为四个发展阶段,贝尔实验室开创了后两个阶段,在简单介绍了该室的主要成就和获得的１１次诺贝尔物理奖之后,理分析了它获得诺贝尔奖的经验,提出了五点启示,特别就通向诺贝尔奖的道路分为基础研究和技术推动科技创新两方面作了说明,以供我国实现诺贝尔奖零点突破和科技转化为生产力决策时作为启示和借鉴。     

Coadsorption of cesium and oxygen on Ni(100): I. Cesium probing of NiO bonding

Low energy electron diffraction (LEED) and work function measurements have been used to study the interaction of Cs and O on (100) surfaces of Ni. Deposition of Cs on oxygen-chemisorbed Ni(100) changed the structure of the O array. The work function of this surface showed a minimum at 0.14 monolayer of Cs coverage and a maximum at 0.29 monolayer. On the other hand, Cs on oxidized Ni(100) could not change the oxygen arrangement at all, and the work function remained constant after reaching a minimum value. These two types of behavior of Cs can be used to probe the bonding states of O on metal surfaces. Our results suggest that the c(2×2) structure of O on Ni(100) is simple chemisorption rather than reconstruction and that the c(2×2) coexists with regions of disordered NiO on Ni(100). While LEED intensity variations detect primarily the chemisorbed c(2×2), other measurements like work function, ion neutralization and sticking coefficient should detect both kinds of NiO bonding.     

V-BLAST系统中一种基于噪声分析的简化最大似然检测算法

该文基于对贝尔实验室垂直分层空时系统中的噪声分析,提出了一种简化的最大似然检测算法。该算法选取多维空间中参考直线附近的若干信号点构成候选子集,并利用最大似然准则在该子集中选取合适的向量作为对发射信号的最终估计。性能分析和仿真表明,该算法在保证接近最优误码性能的前提下,具有更低的计算复杂度,并且解决了噪声增强问题。     

The performance of uplink LDPC‐coded multirelay cooperation based on virtual V‐BLAST processing

This paper proposes an efficient uplink low‐density parity‐check (LDPC)‐coded multirelay cooperation architecture based on virtual Vertical‐Bell Labs Layered Space–Time (V‐BLAST) processing over a Rayleigh fading channel, where minimum mean square error in combination with a successive interference canceller and belief propagation‐based joint iterative decoder based on the introduced multilayer Tanner graph are effectively designed to detect and decode the corrupted received sequence at the destination. By introducing V‐BLAST transmission to coded multirelay cooperation, relays send their symbol streams simultaneously, which significantly reduce the transmission delay and provide higher transmission efficiency. The theoretical analysis and numerical results show that the proposed LDPC‐coded cooperation scheme outperforms the coded noncooperation under the same code rate and achieves a better compromise, with respect to the performance, signal delay, and encoding complexity associated to the number of relays, than the conventional LDPC‐coded cooperations without V‐BLAST transmission. This performance gain can be credited to the proposed V‐BLAST processing architecture and belief propagation‐based joint iterative decoding by the introduced multilayer Tanner graph at a receiver side. Copyright © 2013 John Wiley & Sons, Ltd.     

印制线路板CAF失效研究

阳极导电丝(CAF)是PCB业内近十年来较为热门的可靠性问题之一,当PCBA工作在高温高湿的环境下时,有可能产生沿玻璃纤维生长的阳极导电丝CAF。本文主要以某种典型板材为例,从某板材在不同孔壁间距、不同外加偏压下的CAF性能考察入手,研究CAF产生的机理,并通过模型推算板材在不同外加偏压下的平均失效寿命(MTF),为后续其他板材耐CAF性能的考察提供了理论依据和试验基础。