一种应用于10位SAR ADC的高精度比较器电路设计

提出一种应用于10位逐次逼近型模数转换器(SAR ADC)的高精度比较器,具有精度高、功耗低的特点。该比较器采用差分结构的前置放大电路,提高输入信号的精度,其自身隔离效果减小了锁存器的回踢噪声和失调电压。动态锁存电路采用两级正反馈,有效提高比较器的响应速度。输出缓冲级电路增强输出级的驱动能力,调整输出波形。该比较器电路采用SMIC 65 nm CMOS工艺技术实现,使用Cadence公司Spectre系列软件对进行仿真,设置工作电压2.5 V,采样频率2 MHz,仿真结果表明,比较器的分辨率是0.542 5 mV,精度达到11位,失调电压为1.405μV,静态功耗为63μW,已成功应用于10位SAR ADC。     

一种用于时间交织型SAR ADC的电容校正技术

时间交织型SAR ADC对包括电容失配在内的通道间失配较敏感,其中电容失配既包括通道内的失配也包括通道间的失配,是影响时间交织型SAR ADC性能的重要因素.为了提升时间交织型SAR ADC的性能,基于对SAR ADC中DAC电容失配对时间交织型SAR ADC影响的分析,结合单通道低速工作SAR ADC的电容校正方法,...     

基于Simulink的∑△调制器的非理想性建模

基于Simulink的系统级模型有助于分析开关电容ΣΔ调制器的各种非理想特性,包括时钟抖动、MOS开关噪声、运算放大器的输入参考噪声、有限直流增益、压摆率和比较器的迟滞性等。为建立各非理想特性与调制器性能之间的关系,对一个非理想特性的5阶单比特ΣΔ调制器进行系统仿真,定量得出各非理想特性对调制器性能的影响。该非理想性系统模型有助于在系统级有效制定出各子模块的性能参数。     

一种新型的12位SAR ADC设计

设计了一种12位精度,200 kS/s采样率的逐次逼近型模数转换器(SAR ADC)。针对传统的电容开关切换算法的大电容面积和高功耗,采用一种新型的电容开关切换算法,提高了转换精度,降低了功耗。此外,比较器电路采用一种全差分动态比较器和静态预放大比较器分时工作的方法,进一步降低了功耗。基于TSMC 0.18μm CMOS工艺,对电路进行了设计和仿真。仿真结果表明,在采样率为200 kS/s时,信号噪声失真比(SNDR)为70.94 dB,有效位数(ENOB)为11.49位,功耗为22μW,优值系数(FOM)为38.2 fJ/(Conversion·step)。     

一种基于伪C-2C混合结构DAC的低功耗SAR型ADC

针对传统SAR ADC电容面积大、功耗高的问题,提出一种基于伪C-2C混合结构DAC的10位低功耗SAR ADC。设计基于SMIC 0.18μm CMOS工艺,采用伪C-2C与权重电容混合结构来降低整个DAC所需的单位电容数和ADC的功耗;使用一种新型的单边开关切换策略来降低DAC的非线性,进一步降低功耗。以栅压自举开关作为采样开关来提高电路线性度;通过无预放大动态比较器保持ADC的静态功耗为零,并对传统的动态比较器进行优化,使其在无预放大的情况下具有较小的输入噪声。采用异步时序逻辑使ADC在低功耗的同时保持较高的转换速率。电路在Cadence平台进行仿真验证,仿真结果表明,DAC电容阵列线性度及比较器精度符合ADC应用需求,整体电路实现逐次逼近功能,在7.7MS/s的采样速率下,平均功耗仅为96μW。     

高性能可重构流水线ADC的设计与仿真

提出了一种14 bit、100 MS/s可重构流水线ADC的设计方案,在采样/保持电路、栅压自举开关、折叠式共源共栅运算放大器、可重构控制器等关键电路上均有明显改进,降低了非理想因素对系统的影响,保证了所设计的流水线ADC的指标实现,并对关键模块电路和ADC系统进行了仿真验证。     

ADC误差对系统性能影响的分析与研究

在数据采集系统中，模数转换器(ADC)的误差对系统性能的影响是至关重要的。本主要从直流特性、误差源、温度效应及交流特性等方面，详细讨论了ADC误差对系统性能的影响，并提出了部分校正措施。     

Sigma-Delta微加速度计非理想因素建模与系统级设计

为了简化Sigma-Delta( ∑△)微加速度计接口电路晶体管级的仿真和优化,建立了系统中的非理想因素模型,并在此基础上完成了一种单环结构的∑△微加速度计的系统级设计.分析了敏感结构中固定极板运动、时钟抖动、开关热噪声、运算放大器噪声等非理想因素对系统的影响,并分别建立了Simulink模型.基于所建模型,设计了一种...     

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。     

14位模数转换器MAX 1324的误差分析

在数据采集系统中,模数转换器(ADC)的误差对系统性能的影响是至关重要的.本文主要以MAX1324为例,从直流特性、误差源、温度效应及交流特性等方面,详细讨论了ADC误差对系统性能的影响,并提出了部分校正措施.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。