微处理器与DSP

高性能低成本的新型TMS320C64×DSP 德州仪器(TI)宣布推出TMS320C6412数字信号处理器(DSP),这项价格低廉并具高性能的数字处理技术进一步推动了创新应用的发展.     

软件无线电关键技术的新趋势（下）

DSP是限制软件无线电发展的瓶颈问题，其数据处理速度和精度直接关系到软件无线电台能否实现。目前采用的技术方案主要是数字信号处理技术(DSP)、专用集成电路(ASIC)、现场可编程门阵列(FPGA)以及这几种技术的结合。高速DSP芯片是软件无线电的核心部分。     

一种高效节能移动终端DSP与ARM数据通路实现方法

文章主要是基于第三代移动通信技术,结合移动通信的发展状况,提出了一种在时分同步码分多址系统(简称TD-SCDMA)的高速数据业务下和空闲省电模式下DSP和ARM数据通信实现方法.ARM与DSP之间数据通信采用共享内存方式进行.文章主要有两个创新点:一是由MCU主控变为由DSP主控;二是UE_ID的匹配工作由DSP来完成     

宽带多媒体数字信号处理器--MAP-CA

近年来,高速DSP(Digital SignalProcessor)发展很快,尤其是VLIW(超长指令字)结构成为高端DSP的主流技术,除了传统的通用DSP产品采用VLIW技术外,针对多媒体应用的专门化通用可编程DSP也有了长足进展,例如Philips的Tri-Media系列和Equa-tor的MAP_CA系列等,在我国都已经开始应用于多媒体系统设计中,本文以MAP_CA为例,分析一下这类多媒体处理器的特点和应用。     

DSP运算方法研究

数字信号处理(DSP)相对于模拟信号处理有很大的优越性,主要表现在精度高、灵活性强、可靠性好、易于大规模集成等方面.DSP技术已成为目前电子工业领域发展最为迅速的技术,在各行各业的应用越来越广泛,在我国市场的前景也越来越广阔.简要介绍了DSP的发展历程、技术应用、基本特点以及在我国市场的前景情况,并详细阐述了DSP结构...     

利用多个DSP来设计6声道杜比数字编码

今天的高档音频系统正在增加其复杂性,以促使DSP(数字信号处理器)基本系统向杜比数字发展。这里介绍的用多DSP(一个主DSP,两个或三个从DSP)设计的杜比数字(杜比AC-3)系统不仅适合于今天6声道,而且也考虑了未来8声道的发展;系统的价格和性能都比以前的好;系统看起来硬件较复杂,但用户主要是把精力集中在应用上,而不是了解DSP的处理过程。因此,无论对国内用户和杜比数字处理器板开发者都有参考价值。     

DSP在多媒体移动通信中的应用

随着多媒体移动通信技术的不断发展。数字信号处理(DSP)技术得到了广泛的应用。本文着重阐述了DSP在当今移动通信领域的应用情况。并对其在未来通信技术中的前景进行了展望。     

一种基于FPGA+DSP的处理机硬件架构

为了解决在实时处理中多数合成孔径雷达(SAR)算法存在的运算量大、耗时长等问题,提出基于多核数字信号处理器(DSP)以及串行高速互联接口(SRIO)的一种新硬件解决方法。主要讨论了现场可编程门阵列(FPGA)+DSP架构下采用多核DSP和SRIO实现SAR算法的主要流程,并在多核DSP中使用流水线技术优化快速傅里叶变换(FFT)算法。通过使用多核DSP和流水线技术以及SRIO技术,使数据运算、传输速率更快,达到缩短运算时间的目的。     

可编程DSP加速推进因特网时代的通信步伐

德州仪器(TI)最近宣布三个创记录的DSP,并把它们作为面向通信业下一代产品的发展,如3G无线通信、宽带和影像应用,提供最快的数字信号处理器(DSP)技术。这些最新器件,是前所未有的速度和超低功耗的完美结合,也实现了TI在去年发布高性能TMS320C64x~(TM)DSP内核时的承诺。这些可编程DSP可以使制造厂商通过无线和宽带基础设施首次提供实时、高分辨率的影像和视频信号。     

高速实时数字信号处理技术探析（下）

当前，高速实时数字信号处理(DSP)技术已经取得了飞速的发展；目前单片DSP芯片的速度已经可以达到每秒16亿次定点运算(1600MIPs)。高速实时DSP芯片的主要特点就是采用了各种并行处理技术，包括片内并行和片间并行等。其中，主要的并行DSP芯片包括美国TI公司的TMS320C8x和TMS320C6x，以及美国AD公司的AD-     

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.     

有机发光二极管中ADN掺杂ErQ的1.54μm电致发光

自行设计了基于8-羟基喹啉铒(ErQ)为发射层(EMLs)和二硝酰胺铵(ADN)为蓝光主体材料的近红外有机发光二级管.器件的基本结构为(p-Si/NPB/EML/Bphen/Bphen:Cs2CO3/Sm/Au),设计并比较了三套不同发射层结构(ErQ/ADN为双层结构器件,(ErQ/ADN)×3为多层结构器件,ErQ:ADN为掺杂结构器件)的器件.三组器件在一定的偏压下,均可发出1.54μm的光,对应三价铒离子4I13/2→4I15/2的跃迁.其中,ADN:ErQ(1∶1)掺杂结构的近红外电致发光强度是ADN/ErQ双层结构中的三倍.此外,不同掺杂浓度的ADN:ErQ复合膜做了以下表征:吸收谱、光致发光谱和荧光寿命谱.实验结果证实了在近红外电致发光过程中存在从ADN主体分子到ErQ发射分子的高效率的能量转移.     

Emerging interconnects: a state-of-the-art review and emerging solutions

Aluminium was a primary material for interconnection in integrated circuits (ICs) since their inception. Later, copper was introduced as interconnect material which has better metallic conductivity and resistance to electromigration. As the aggressive technology scaling continues, the copper resistivity increased because of size effects, which causes increase in delay, power dissipation and electromigration. The need to reduce the resistor-capacitor??????? delay, dynamic power utilisation and the crosstalk commotion is as of now the fundamental main impetus behind the presentation of new materials. The purpose of this paper is to do a survey of interconnect material used in IC from introduction of ICs to till date. This paper studies and reviews new materials available for interconnect application which are optical interconnects, carbon nanotube (CNT), graphene nanoribbons (GNRs) and silicon nanowires which are alternatives to copper. While doing a survey of interconnect material, it is found that multiwalled CNTs, multilayer GNR and mixed CNT bundles are promising candidates and are ultimate choice that can strongly address the problems faced by copper but on integration basis copper would last for coming years.     

钠离子对poly(dT).poly(dA).poly(dT)三螺旋DNA分子呼吸模式的影响

利用分子结构的螺旋对称性,建立了一个包括钠离子的三链DNA分子poly(dT)*poly(dA)*poly(dT)的晶格动力学模型,计算了poly(dT)*poly(dA)*poly(dT)的氢键呼吸模式.结果发现钠离子的加入明显地淬灭了位于较低频率的几个最为强烈的Hoogensteen氢键呼吸模式,而对Watson-Crick氢键呼吸模式影响不明显,这说明钠离子能提高poly(dT)*poly(dA)*poly(dT)三螺旋结构的稳定性.该计算结果很好地解释了poly(dT)*poly(dA)*poly(dT)的热融化实验.     

人小肠粘膜免疫酶的定位研究—光镜和电镜免疫组织化学染色法

本文对免疫酶组织化学的样品制备程序和染色方法做了详细的阐述。用直接法、间接法和ABC法,对人小肠免疫酶的定位,进行了光镜和电镜的观察,染色阳性反应显著,获得了满意的效果。并对染色技巧做了分析和探讨。     

聚对苯撑苯并双(口恶)唑发光及其器件制备

采用光谱技术,研究了聚对苯撑苯并双(口恶)唑(PBO)溶液的光敏发光特性,并用相对法估算出溶液发光效率在50%范围.结合光谱技术、半导体电学和电化学等研究手段,具体研究了以PBO为发光层的单层电致发光器件,研究结果显示,电致发光与薄膜的光致发光有具有相同的发光中心,峰值位于510 nm左右.同时发现,由于存制备过程中不同处理条件使得不同厚度薄膜残留的掺杂物质浓度不同,从而引起薄膜的导电性的不同.使得器件的阈值场强随PBO厚度的减小而逐渐增加.     

BNBST无铅压电陶瓷的制备工艺研究

设计了（Bi0.55Na0.5）1-X（BaaSrb）xTiO3（BNBST[100x-100a／100b]）无铅压电陶瓷新体系。该体系压电陶瓷具有工艺特性及压电响应好，压电常数高的特点，且有实际应用前景的新型压电陶瓷材料体系。采用传统的陶瓷工艺制备了（Bi0.55Na0.5）1-X（BaaSrb）xTiO3无铅压电陶瓷，研究了制备工艺参数对其物化结构性能的影响。生料的热重-差热（TGA-DTA）分析表明，粉料合成过程中，先是SrTiO3、BaTiO3的形成，然后是（Bi0．5Na0．5）Tio，的形成，同时三者形成固溶体；密度测试表明，陶瓷的体积密度随烧结温度的升高而增大，可较易获得理论密度94％的陶瓷；X-射线能谱分析（EDAX）研究表明，陶瓷的Bi、Na的挥发随着烧结温度的升高而加剧。研究结果表明，要制备性能优良的无铅压电陶瓷，需要精确控制制备工艺。     

Arsenic deposition as a precursor layer on silicon (211) and (311) surfaces

We investigate the properties of arsenic (As) covered Si(211) and Si(311) surfaces by analyzing data from x-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED) images. We then create a model using total surface energy calculations. It was found that both Si(211) and Si(311) had 0.68±0.08 surface As coverage. Si(211) had 0.28±0.04 Te coverage and Si(311) had 0.24±0.04 Te coverage. The Si(211) surface replaces the terrace and trench Si atoms with As for a lower surface energy, while the Si edge atoms form dimers. The Si(311) surface replaces all terrace atoms and adsorbs an As dimer every other edge site. These configurations imply an improvement in the mean migration path from the bare silicon surface by allowing the impinging atoms for the next epitaxial layer, tellurium (Te), to bind at every other pair of edge atoms, and not the step terrace sites. This would ensure a nonpolar, B-face growth.     

Joint estimation of TOA and DOA in IR-UWB system using a successive propagator method

Impulse radio ultra-wideband (IR-UWB) ranging and positioning require accurate estimation of time-of-arrival (TOA) and direction-of-arrival (DOA). With receiver of two antennas, both of the TOA and DOA parameters can be estimated via two-dimensional (2D) propagator method (PM), in which the 2D spectral peak searching, however, renders much higher computational complexity. This paper proposes a successive PM algorithm for joint TOA and DOA estimation in IR-UWB system to avoid 2D spectral peak searching. The proposed algorithm firstly gets the initial TOA estimates in the two antennas from the propagation matrix, then utilises successively one-dimensional (1D) local searches to achieve the estimation of TOAs in the two antennas, and finally obtains the DOA estimates via the difference in the TOAs between the two antennas. The proposed algorithm, which only requires 1D local searches, can avoid the high computational cost in 2D-PM algorithm. Furthermore, the proposed algorithm can obtain automatically paired parameters and has better joint TOA and DOA estimation performance than conventional PM algorithm, estimation of signal parameters via rotational invariance techniques algorithm and matrix pencil algorithm. Meanwhile, it has very close parameter estimation to that of 2D-PM algorithm. We have also derived the mean square error of TOA and DOA estimation of the proposed algorithm and the Cramer-Rao bound of TOA and DOA estimation in this paper. The simulation results verify the usefulness of the proposed algorithm.     

系统级封装新型埋入式电源滤波结构的研究

在高密度小尺寸的系统级封装(SiP)中,对供电系统的完整性要求越来越高,多芯片共用一个电源网路所产生的电压抖动除了会影响到芯片的正常工作,还会通过供电网路干扰到临近电路和其他敏感电路,导致芯片误动作,以及信号完整性和其他电磁干扰问题.这种电压抖动所占频带相当宽,几百MHz到几个GHz的中频电源噪声普通方法很难去除.结合埋入式电容和电源分割方法的特点,提出一种新型高性能埋入式电源低通滤波结构直接替代电源/地平面.研究表明,在0.65～4GHz的频带内隔离深度可达-40～75 dB,电源阻抗均在0.25ohm以下,实现了宽频高隔离度的高性能滤波作用.分别用电磁场和广义传输线两种仿真器模拟,高频等效电路模型分析这种低通滤波器的工作原理以及结构对隔离性能的影响,并进行了实验验证.