凌力尔特推出16位低功率125 Msps ADC

凌力尔特公司(Linear Technology Corporation)推出3个低功率16位、25~125 Msps模数转换器(ADC)系列。LTC2165和LTC2185系列分别为单通道和双通道同时采样并行ADC,可提供全速率CMOS或双数据速率(DDR)CMOS/LVDS数字输出选项,并具有可编程数字输出定时、可编程LVDS输出电流和任选的LVDS输出终端。LTC2195系列包括具串行LVDS输出的双通道、同步采样ADC。每个ADC系列都提供了一种引脚兼容的转换器选择,采样速率最高可达125 Msps,并专为在额定速度条件下实现极低功耗而优化。凌力尔特推出16位低功率125 Msps A     

用于高速CMOS图像传感器的电容复用型循环ADC

设计了一种用于高速CMOS图像传感器的列并行标志冗余位(RSD)循环式模/数转换器(ADC)。该ADC在每次循环中采样和量化输入信号同步进行,速度比传统的循环式ADC提高了1倍。利用电容复用技术,对于像素输出信号的相关双采样(CDS)操作和精确乘2运算,将仅使用1个运放和4组电容来实现,减小了芯片面积。通过0.18μm标准CMOS工艺完成了ADC电路设计和仿真。SPICE仿真结果表明,在4 MS/s的采样速度和1.8 V电源电压下,ADC的SNDR达到55.61 dB,有效位数为8.94 bit,功耗为1.34 mW,满足10 bit精度高速CMOS图像传感器系统的应用要求。     

降低高速,高分辨率ADC复杂性的一种设计

本文介绍了一种能降低高分辨率闪烁模／数转换器（ADC）电路复杂性的一种设计．这种高速、高分辨率ADC采用低分辨率的标准闪烁ADC板块组成，只需串联K个n位的标准闪烁ADC模块就可以构成一个k·n位高速ADC．使用本文提出的方法，可以很容易地用低分辨率的标准闪烁ADC模块实现4位和32位高速ADC．     

凌力尔特推出16位低功率125MspsADO

凌力尔特公司（LinearTechnologyCorporation）推出3个低功率16位、25～125Msps模数转换器（ADC）系列。LTC2165和LTC2185系列分别为单通道和双通道同时采样并行ADC,可提供全速率CMOS或双数据速率（DDR）CMOS／LVDS数字输出选项,并具有可编程数字输出定时、可编程LVDS输出电流和任选的LVDS输出终端。LTC2195系列包括具串行LVDS输出的双通道、同步采样ADC。     

一种改进的流水线ADC开关电容电路

为降低流水线模数转换器(ADC)中跨导运算放大器(OTA)设计要求,在分析已有开关电容电路(SC)误差消除技术和流水线ADC误差源的基础上,提出一种改进的流水线ADC开关电容电路及与其匹配的OTA设计方案.采用交又差分结构,对虚地电容进行了修正,并将电容失配参数在系统传输函数中消去,使开关电容电路对OTA的增益误差要求降低,并使其瞬态功耗下降.采用CMOS 0.18üm工艺设计了一个分辨率为8位、取样速率200 MHz的ADC作为验证原型,仿真结果表明,该优化结构符合ADC电路高速低功耗要求,可作为信号前端处理模块应用到模数转换电路中.     

12位电容电阻混合式SAR ADC IP核的设计

在深入分析逐次逼近型的模数转换器SAR ADC的基础上,对内置DAC和比较器的设计进行了优化,实现了一款适用于工业控制器的SAR ADC IP核的设计.芯核采用0.18 μm CMOS Mix_singal IP6M工艺,分别采用3.3 V的模拟电源电压和1.8 V的数字电源电压供电,仿真结果表明,该SAR ADC IP核实现了12 bit的精度.IP核的面积为800μm×420 μm,FF case下功耗为1.2 mW,微分非线性误差DNL＜0.5 LSB.     

4．5GHz下的试验

IBM的研究人员最近展示了新一代的高效计算机电路,它们可以以3.3GHz到4.5GHz的速度运行,但功率却只有现有的高性能处理器的一半。 该电路使用标准的硅晶体管和一种被称作互锁式流水线型CMOS(InterlockedPipeline CMOS,IPCMOS)以提高时钟频率。传统的体系结构使用集中的时钟频率,在     

用于CMOS图像传感器的高速高精度斜坡ADC设计技术研究

针对CMOS图像传感器中传统的列级单斜式ADC在速度方面的不足和两步式ADC在斜坡间切换过程中的非线性问题,论文提出了一种基于时间共享与单区间的高速高精度列并行两步式斜坡ADC架构.采用像素电荷转移阶段的电位识别,实现了不消耗时间的粗量化;采用单区间高精度量化,解决了多斜坡之间的无缝衔接问题.所提出的方法在一款基于55 nm 1P4M工艺的2048×2048规模的CMOS图像传感器芯片中进行了有效性验证,结果表明,在12位分辨率下,该方法相较于传统的两步式结构,行时间可以压缩到500 ns,DNL和INL都可以控制到0.12LSB以内,单列功耗仅为16.5μW.     

一种应用于10 MHz 8位SAR ADC的分段式DAC电路设计

为了实现8位高性能的SAR ADC,设计了一种应用于8位SAR ADC的分段式结构DAC电路。采用二进制电容阵列,减小电容取值范围,有效提高精度,同时加快电容充放电速度,有效降低功耗,减小面积和成本。采用SMIC 65 nm CMOS工艺,工作于1.2 V电源电压,10 MHz采样频率,使用Cadence公司Spectre系列软件对设计的电路进行仿真。仿真结果显示,该分段式DAC电路可以有效实现8位数模转换,已成功应用于8位SAR ADC。     

一种应用分段式电容阵列的20 MS/s 10-bit SAR ADC

设计了一个10位分辨率，20 MS/s采样率的逐次逼近型模拟数字转换器(SAR ADC)。该电路通过采用分段式电容阵列设计，缩短了量化过程中高位电容翻转后所需要的稳定时间，从而提高了量化速度。此外，还提出了一种新颖、高效的比较器校准方法，以较低的成本实现了比较器失调电压的抑制。该ADC芯片基于180 nm CMOS工艺设计制造，核心面积为0.213 5 mm²。实际测试结果表明，在1.8 V电源电压、20 MS/s采样频率下，该ADC的信号噪声失真比(SNDR)达到了58.24 dB。     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

法律信息库系统

本文分析了法律数据库的结构和特点，介绍了采用面向对象设计方法和超文本数据库技术开发和实现法律信息库系统将作为重要网络资源之一为不同用户进行法律咨询服务。     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

International Journal of Automation and Computing Table of Contents

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Information for authors

正SCIENCE CHINA Information Sciences(Sci China Inf Sci),cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press,is committed to publishing highquality,original results of both basic and applied research in all areas of information sciences,including computer science and technology;systems science,control science and engineering(published in Issues with odd numbers);information and communication engineering;electronic science and technology(published in Issues with even numbers).Sci China Inf Sci is published monthly in both print and electronic forms.It is indexed by Academic OneFile,Astrophysics Data System(ADS),CSA,Cabells,Current Contents/Engineering,Computing and Technology,DBLP,Digital Mathematics Registry,Earthquake Engineering Abstracts,Engineering Index,Engineered Materials Abstracts,Gale,Google,INSPEC,Journal Citation Reports/Science Edition,Mathematical Reviews,OCLC,ProQuest,SCOPUS,Science Citation Index Expanded,Summon by Serial Solutions,VINITI,Zentralblatt MATH.     

Erratum to: Fast global kernel fuzzy c-means clustering algorithm for consonant/vowel segmentation of speech signal

正Erratum to:J Zhejiang Univ-Sci C(ComputElectron)2014 15(7):551-563doi:10.1631/jzus.C1300320The original version of this article unfortunately contained mistakes.Algorithm 6 should be as follows:Algorithm 6 FGKFCM-F clustering Input:(1)X={x_1,x_2,…,x_N},,x_iR~d,i=1,2,…,N,the dataset;(2)C,1C≤N,the number of clusters;(3)ε0,the stopping criterion;     

Journal of Zhejiang University-SCIENCE C (Computers & Electronics) Total contents

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A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.