电源变压器噪声干扰的抑制

本文从分析电源变压器的结构入手，提出了采用静电屏蔽、隔离变压器及初次级平衡式绕组新工艺等方法，以解决电源变压器的噪声干扰问题。     

低压降CMOS稳压器的电源噪声抑制分析

通过对低压降CMOS稳压器工作原理的分析,给出了一种频域分析模型。基于此模型,对低压降稳压器的电源噪声抑制进行了分析和研究,得到了低压降稳压器在频域的传递函数;依据此传递函数,给出了改善电源噪声抑制的方法。此外,给出了几种有效提高电源噪声抑制的方法和电路。     

高速数字电路电源分配网络设计优点与噪声抑制分析研究

高速数字电路电源分配网络设计改变了传统的人工控制芯片模式，实现了智能管理控制系统的新突破，为人们随时随地的远程管理提供了优良的服务。本文主要结合电路电源分配网络系统的产品特点、技术优点、噪声原因分析和有效抑制噪声的措施，来说明高速数字电路技术的应用，通过其查询、联通、监控和故障报警等功能，完成人们所见即所得的控制管理，节省了人力、物力和经济成本的开支，行之有效的为生活带来了方便和实惠。     

曲率补偿基准源设计及其电源噪声抑制分析

基于传统基准源的研究和分析,利用低压差调整器的原理和结构,通过插入失调电压对基准进行曲率补偿,得到一种新型曲率补偿CMOS带隙基准电压源.对基准源的低频电源噪声抑制和系统稳定性进行了推导和分析.测试结果表明,在20～100 ℃的温度范围内,基准电压在1.31235～1.31241 V,温度系数约为1 ppm/℃,低频下PSRR提高到90 dB;电路功耗为2.18 mW,版图面积为0.09 mm2.     

门级电源噪声分析

SPICE仿真器采用的是在晶体管级进行分析的方法,最近又出现了采用其它方法对芯片内电源噪声进行动态分析的趋势。其中,最为引人注目的是将分析抽象度提高到门电路级的电源噪声分析方法,而且,E D A 工具供应商—美国的Apache　Design　Solutions 和Sequence　Design等公司已经开始提供相应的产品。据Apache公司称,该产品将在一天内完成2000万门LSI电路芯片的动态电源噪声分析”(见图A-1)。目前,瑞萨等半导体生产厂家正在对这些产品进行评估。要进行门级动态电源噪声分析,大致需要具备三种信息。第一,静态的定时信号信息--哪个逻辑单…     

高速嵌入式系统中电源噪声抑制方法

根据平面腔体谐振模型理论推导出高速嵌入式电路电源平面对阻抗函数关系式,分 析了电源平面对的谐振特性与PCB板材、介质层厚度以及导体平面的电导率之间的关系,得 出可通过减小介质层厚度、使用高介电常数的介质材料以及增加介质损耗等3种方法来抑制 电源平面对的谐振效应,并使用全波仿真方法验证了可行性。从时域仿真了高速电路中的噪 声传播与电源平面谐振的相互关系,结果表明,通过抑制电源平面对谐振阻抗可将电源噪声 减 小至原有结构的15%,从而有效提高系统的电源完整性。     

噪声与噪声抑制滤波器

本文对电磁噪声的传播途径,避免噪声干扰的方法,用于吸收及滤除电磁噪声的各类噪声抑制滤波器的结构、特性、应用范围和选用此类滤波器应予注意的事项作了扼要的介绍。     

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.     

腾飞的触摸技术——2010年显示周

由于去年显示周上大量的有关触摸技术的研究报告及参展商,因此在2010年信息显示学会专门为触摸技术成立了研讨会。该会议的主要内容是:触摸技术的发展,多点触摸系统及其发展,嵌入式显示触摸技术的解决方案。此外,还有9个关于触摸技术介绍性的海报会议。     

腾飞的触摸技术——2010年显示周

由于去年显示周上大量的有关触摸技术的研究报告及参展商,因此在2010年信息显示学会专门为触摸技术成立了研讨会。该会议的主要内容是：触摸技术的发展,多点触摸系统及其发展,嵌入式显示触摸技术的解决方案。此外,还有9个关于触摸技术介绍性的海报会议。     

Overcoming the Cut‐Off Charge Transfer Bandgaps at the PbS Quantum Dot Interface

Light harvesting from large size of semiconductor PbS quantum dots (QDs) with a bandgap of less than 1 eV is one of the greatest challenges precluding the development of PbS QD‐based solar cells because the interfacial charge transfer (CT) from such QDs to the most commonly used electron acceptor materials is very inefficient, if it occurs at all. Thus, an alternative electron‐accepting unit with a new driving force for CT is urgently needed to harvest the light from large‐sized PbS QDs. Here, a cationic porphyrin is utilized as a new electron acceptor unit with unique features that bring the donor–acceptor components into close molecular proximity, allowing ultrafast and efficient electron transfer for QDs of all sizes, as inferred from the drastic photoluminescence quenching and the ultrafast formation of the porphyrin anionic species. The time‐resolved results clearly demonstrate the possibility of modulating the electron transfer process between PbS QDs and porphyrin moieties not only by the size quantization effect but also by the interfacial electrostatic interaction between the positively charged porphyrin and the negatively charged QDs. This approach provides a new pathway for engineering QD‐based solar cells that make the best use of the diverse photons making up the Sun's broad irradiance spectrum.     

Source Coding With Limited-Look-Ahead Side Information at the Decoder

We characterize the rate distortion function for the source coding with decoder side information setting when the ith reconstruction symbol is allowed to depend only on the first i+lscr side information symbols, for some finite look-ahead lscr, in addition to the index from the encoder. For the case of causal side information, i.e., lscr=0, we find that the penalty of causality is the omission of the subtracted mutual information term in the Wyner-Ziv rate distortion function. For lscr>0, we derive a computable "infinite-letter" expression for the rate distortion function. When specialized to the near-lossless case, our results characterize the best achievable rate for the Slepian-Wolf source coding problem with finite side information looka-head, and have some surprising implications. We find that side information is useless for any fixed lscr when the joint probability mass function (PMF) of the source and side information satisfies the positivity condition P(x,y)>0 for all (x,y). More generally, the optimal rate depends on the distribution of the pair X,Y only through the distribution of X and the bipartite graph whose edges represent the pairs x,y for which P(x,y)>0. On the other hand, if side information look-ahead is allowed to grow faster than logarithmic in the block length, then H(X|Y) is achievable. Finally, we apply our approach to derive a computable expression for channel capacity when state information is available at the encoder with limited look-ahead     

“视”不可挡

自从"高清"步入人们的生活之后,影院般的享受逐渐成为人们的一项追求的目标。将电影院搬回家的梦想已经使许许多多人为这而奋斗。电影院里大画面、高清晰度和震撼的音响令人宛如入画、身临其境。如果要在家中取得电影院般的冲击力、视觉满足将是首要重点,因此大屏幕Full HD全高清的平板电视自然成为人们选择的目标。因为只有够大,"视"上才能获得满足,此为不可阻挡的观赏理由。     

Source coding with cross observations at the encoders (Corresp.)

A source coding problem is considered which generalizes the Slepian-Wolf-Cover theorem on noiseless coding of correlated sources so as to include the case of arbitrary cross observations at the encoders. The achievable rate region is established by using Cover's result. Also a co-polymatroidal property of the relevant polytope is pointed out.     

Source coding with side information at several decoders

A source coding problem is considered which generalizes source coding with side information [1], [2]. Three correlated information sourcesX,YandZ, are block-encoded:Yis to be reconstructed by two different decoders, one having access to the encoded version ofXand the other having access to the encoded version ofZ. The region of achievable rates is determined, assuming that thc sources are discrete, memoryless, and stationary. The resuit is generalized to an arbitrary finite number of decoders.     

灰名单将垃圾邮件挥之而去——CP Secure内容安全网关成功解决方案

网络安全已不再是IT行业的专有名词,它遍及了所有领域,只要与互联网相连的地方就存在安全问题,与此同时,网络安全的地位也在急速上升,得到企业及个人用户越来越多的关注。