低功耗编译技术综述

功耗问题已经成为制约电子系统发展的重要因素.功耗是由硬件在运行软件时产生的,软件的数据存取和指令执行都会使硬件产生功耗.编译器可以通过适当的调度优化,改变软件在硬件上的运行轨迹,使得硬件执行某一个程序时的功耗变小.本文从如何对软件的功耗进行评估和如何实现低功耗的编译两大方面对低功耗编译的相关研究进行了广泛介绍,着重评述了专门的低功耗编译技术.最后对当前低功耗编译存在的问题做了分析,给出了对于低功耗编译新方向的预测.     

基于硬件构件的嵌入式系统低功耗研究

降低系统功耗不仅要考虑硬件方面的因素,同时也要分析因软件引起的功耗。为了降低系统整体功耗,首先需要明确影响系统功耗的软硬件因素。在硬件方面,通过对硬件构件进行选择、设计和整合等方法降低功耗;软件方面则是重点优化与功耗密切相关的要素,如算法、指令与方法等。这些因素往往是相互制约、相互影响的。设计一个成功的低功耗系统,需要通过分析与实验,明确一个以硬件构件为思想的嵌入式系统低功耗设计时所需考虑的一些问题。     

Android手机低功耗GPS导航软件设计与实现

随着智能手机功能日益丰富完善以及移动互联网的迅速发展,智能手机的功耗管理就显得越来越重要了.传统的关于功耗管理都是从显示屏、网络模块(GPRS/WiFi)和处理器等入手,文中通过优化GPS软件实现低功耗.通过阐述现在导航软件的工作原理并分析手机定位导航功耗情况,最后通过对比测试当前android系统4大主流导航软件功耗情况,并结合自己提出的低功耗编程以及软件运行流程,设计并实现了一款低功耗GPS导航软件,通过测试,验证了该软件的可行性以及低功耗特性.     

嵌入式系统低功耗设计研究

在嵌入式系统设计中低功耗设计是许多设计人员必须面对的问题,其原因在于嵌入式系统产品不是一直都有充足的电源供应,往往是靠电池来供电的,而且大多数嵌入式设备都有体积和质量的约束。另外,系统部件产生的热量和功耗成比例,为解决散热问题而采取的冷却措施进一步增加了整个系统的功耗。为了得到最好的结果,在系统设计时就必须考虑低功耗问题。系统的功耗设计涉及到软件、硬件、集成电路工艺等多个方面,这里分析了功耗产生的原因,从原理和实践上探讨系统的低功耗设计问题,综述硬件低功耗和软件低功耗的设计方法,给出实现低功耗设计的一种可行方法。     

低功耗MCU系统软硬件设计考虑

电子产品的低功耗问题经常让产品设计者头痛而又不得不面对.以单片机(MCU)为核心的系统,其功耗主要由单片机功耗和单片机外围电路功耗组成.要降低单片机系统的功耗,需要从硬件和软件两方面人手.     

嵌入式智能系统底电流的调试方法

本文针对如何获得嵌入式系统低功耗状态下的准确电流值的方法进行了阐述和验证。硬件使用Intel PXA270芯片构成的最小系统为基础,提出了软件先在bootloader中进行系统进入低功耗状态和退出低功耗状态的调试方法。分析了最小系统睡眠时功耗值与配有其它外围设备的嵌入式系统睡眠时功耗值相同的原因。     

嵌入式系统的低功耗设计技术

随着嵌入式系统的广泛应用,低功耗问题摆在了设计人员面前.低功耗设计包括系统设计、硬件设计、软件设计、器件的工艺设计等诸多方面.其中器件的工艺设计主要由半导体器件的厂家来完成,嵌入式系统的应用设计人员只需要关心器件的功耗指标,更多的工作集中于系统的硬件、软件以及它们之间的配合方面.本文主要从这些方面讨论嵌入式系统的低功耗设计问题和设计方法.     

基于C8051F040单片机的便携式心电监护仪的低功耗设计

在便携式心电监护仪器设计中,微处理器是影响系统功耗的重要因素,可以通过对微处理器内部资源的设计来降低整个系统的功耗.C8051F040单片机是一低电压供电(2.7～3.6V),集成度更高,运行速度更快的8位CIP51处理器,因此C8051F040单片机在低功耗系统设计中具有很大优势,在便携式心电监护仪的设计中,我们采取了一系列的硬件和软件措施,系统功耗降低了近30%.     

Silabs MCU低功耗优势及其实现方法

现在的电子产品，对低功耗的要求越来越高。产品功耗的问题是经常让产品设计者头痛而又不得不面对的一个问题。以单片机为核心的系统，其功耗主要由单片机功耗和单片机外围电路功耗组成。要降低单片机系统的功耗，需要从硬件和软件两方面入手。     

基于ARM的便携式系统的功耗管理

ARM微处理器因其高性能和低功耗的特性,特别适合于便携式系统的应用。而系统级的问题对于有效的功耗管理也是非常重要的。本文主要对硬件及系统的功耗管理作一些介绍。功耗管理电路能尽可能地降低便携式系统的用电量。最主要的优点是延长电池的使用寿命,当然还有其他一些优点,如减少散热量等。充分了解系统各部分组件的耗电情况、降低系统哪部分耗电量比较合理等问题是至关重要的。图 1 所示为PDA类产品的功耗分布情况。功耗管理是由软件、处理器、外设、电源等一起构成的系统问题。处理器便携式系统的处理器中有大量与系统其他电路相连…     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.