FireWire高速串行总线(IEEE 1394)及其应用前景

介绍了ＦｉｒｅＷｉｒｅ高速串行总线（即ＩＥＥＥ１３９４）的结构、性能特点及其应用前景。     

高速串行总线——IEEE1394

“ＦｉｒｅＷｉｒｅ”，“ＩＥＥＥ—１３９４”，“ＩＥＣ１８８３”……都是指一种高速串行总线，实际上，这是在ＰＣ机和消费类电器设备间进行数据传输的一种新的标准。由Ａｐｐｌｅ计算机公司命名的“ＦｉｒｅＷｉｒｅ”源于低价消费类产品间连接应用的需要，它们有大量的视听数据需要记录、编辑、存储和传输。总线的性能，灵活性和易于使用性通过外部ＰＣ机和Ｃ尺寸ＶＸＩ主机箱间的Ｉ／Ｏ互连得以实现。之所以能实现ＩＥＥＥ－１３９４的低价格，部分是通过采用经简化电缆设计的串行数据传输。ＩＥＥＥ—１３９４的电缆介质可允许在一…     

VXI总线

ＶＸＩ总线ＶＸＩｂｕｓ￥／／ＶＸＩ总线（ＶＸＩｂｕｓ）是ＶＭＥｂｕｓｅｘｔｅｎｓｉｏｎｆｏｒＩｎｓｔｒｕｍｅｎｔａｔｉｏｎ总线的英文缩写。其意即ＶＭＦ总线在仪器领域的扩展或ＶＭＥ总线的仪器扩展总线．总线亦是将多个电信号从一个源或多个源传送到一个或多个...     

VXI总线在换热器综合性能测试中的应用

介绍了ＨＰ７５００系列ＶＸＩ总线模块仪器构成换热器性能测试系统的硬件选择和配置及用ＨＰ ＶＥＥ图形化编程方法。     

组建一个GPIB－VXI总线系统

普通的控制ＶＸＩ总线仪器的方法是使用一个ＩＥＥＥ４８８控制器，集成ＶＸＩ总线仪器的任务只不过就是增加一个ＶＸＩ总线主机箱、一个０号槽模件和几个ＶＸＩ总线仪器。     

基于LXI仪器总线的分布式测试系统

LXI仪器总线是继GPIB、VXI、PXI仪器总线之后的、新一代基于以太网络LAN的总线技术,适用于自动测试系统的模块化仪器平台标准;文章在论述仪器总线发展、LXI总线系统结构和主要特点的基础上,给出了一种基于LXI仪器总线的分布式测试系统的系统总体结构,并对网络消息触发,IEEE1588时钟同步触发和LXI触发总线三种不同的同步测试策略进行了比较和分析,可以根据测试对象的远近、分散程度进行合适选择.     

WorldFIP现场总线在中国的应用前景看好

◆ 前言ＩＥＣ６１１５８现场总线标准包含了８个子集、７种不同的现场总线方案。ＩＥＣ是把最终的选择留给了用户。从技术角度看 ,这个结果也有其合理性 :现实的世界是丰富多彩的 ,没有一种现场总线对任何类型工业控制的各个层次都能是最好的。对关心现场总线技术的用户、系统集成商和供应商来说 ,此时需要全面了解各种总线的特点 ,根据自己行业的特点 ,选择一种最适合的总线方案。◆ＷｏｒｌｄＦＩＰ是用户支持的现场总线在９９年底进行的对ＩＥＣ现场总线国际标准６１１５８投票中 ,代表ＷｏｒｌｄＦＩＰ意见的法国代表团投的是反对票 ,…     

惠普和航天测控公司加强合作 联手开发VXI产品取得丰硕成果

惠普和航天测控公司加强合作联手开发ＶＸＩ产品取得丰硕成果ＶＸＩ总线是一种模块化仪器总线，由于它吸收了ＶＭＥ总线高速通讯和ＧＰ－ＩＢ易于组合的优点，近年来在欧美各发达国家的高科技市场上已逐步成为占主导地位的测试和测量技术。为提高我国自动化测试和测量技术...     

VXI总线仪器动态数据采集系统

动态数据采集系统是对动态信号分析的关键，要求能够对动态信号进行快速、高准确度的数字化并高速存储。ＶＸＩ总线仪器从结构，操作控制方式，数据存储及传输速率等方面都具有显著的特点。本文详细分析了ＶＸＩ总线仪器ＨＰ Ｅ１４３０Ａ和ＨＰ Ｅ１４２８的应用特点和相关的技术指标；阐述了利用ＨＰ Ｅ１４３０Ａ、ＨＰ Ｅ１４２８及ＨＰＶＥＥ组建快速、高准确度动态数据采集系统的方法和校准过程，并给出了在关软件流程图。     

基于LXI的合成仪器测试系统

从测试系统的发展历程入手,介绍了合成仪器测试系统的设计与实现,详细讨论了LXI的标准规范及主要特点,LXI总线关键技术,以及基于LXI总线合成仪器的结构,阐述了LXI模块化测试平台在虚拟仪器和自动测试领域的应用前景.     

FireWire finally comes home

The article discusses the IEEE 1394 networking standard, otherwise known as FireWire. FireWire was designed to link personal computers, digital cameras, televisions, DVD players, printers, and other home electronics equipment. At the time FireWire seemed like a perfect idea whose time had come, but there was one small problem: a competing technology, called Universal Serial Bus (USB), promised to do nearly the same thing. Like FireWire, USB can connect multiple peripherals to a single port on the back of our computers. But USB is designed to be a simpler, slower interface that is less expensive to manufacture. Because both technologies arrived at about the same time, hardware and software vendors had to make a choice as to which technology to develop and support. USB got the nod in the Wintel world-with Windows driver support for USB peripherals as early as October 1996-but it wasn't until Windows 98 that consumers got full OS support for USB. Early support on the Wintel platform, however, could account for the large number of USB components that have been popping up over the past two years, such as speakers, joysticks, printers, video cameras, and the like, all of which have made it to market much more quickly than FireWire based technologies. The prospect of the increasing use of FireWire is discussed     

Testing methodology for FireWire

This article describes a methodology for testing a high-performance serial bus interface commonly referred to as FireWire. Specified by the IEEE 1394 document, FireWire is offered by IC manufacturers in various scalable configurations. In general, it is a low-cost device used to provide a highspeed data path between various systems and products, such as PCs and video devices. FireWire is also usable as a backplane bus interconnect. Application-specific IC manufacturers offer FireWire standard cells for use in custom device designs. To assure cost-effective production, the tester and implementation costs must be reasonable, the execution time must be short, and test results must be accurate. Our methodology fulfils these goals with a minimum of compromises. We validated it using a plastic leaded chip carrier device with an 8-bit parallel port and multiple serial ports on an Advantest T6682 VLSI Logic Test System     

A little journey inside Windows memory

In 2005 and 2006, two security researchers, Maximilian Dornseif and Adam Boileau, showed an offensive use of the FireWire bus. They demonstrated how to take control of a computer equipped with a FireWire port. This work has been continued. After a brief summary of how memory works on modern OS, we will explain how the FireWire bus works, and it can be used to access physical memory. Since modern operating system and processors use virtual addresses (and not physical ones), we rebuild the virtual space of each process in order to retrieve and understand kernel structures. Thus, we now have an instant view of the operating system without being submitted to the security protections provided by the processor or the kernel. We will demonstrate several uses for this. First we will show what can be done only with an interpretation of kernel structures (read access). For example, we can have the list of all processes, access to the registry with no control even for protected keys like the SAM ones. This is used to dump credentials. Then, we see what can be done when one modifies the memory (write access). As an example, we show a 2 byte patch to unlock a workstation without knowing the password. Last but not least, code execution is not supposed to happen through FireWire since it is only a bus providing read/write access to the memory. However, slightly modifying the running kernel lets us do whatever we want. We will explain how to have a shell with SYSTEM privileges before any authentication.     

中央医用监护系统网络通信设计

设计了基于Windows平台下的中央医用监护仪网络系统,利用微机串行通信适配器与各分机采用半双工的主从通信方式实现了测量生命参数的高速、远距离通信,制定了通信协议、数据格式及数据打包方式.该系统的设计原理具有广泛的适应性和较高的性能价格比,可应用于其他测控仪器、仪表的高速远程通信.     

基于无线传感网的土壤呼吸测量系统

LI-COR公司开发的LI-8100系列土壤碳通量测定仪被广泛用于土壤呼吸测定。但该仪器价格昂贵、测量能耗高，难以满足土壤碳通量测定的多点实时测量要求。本文提出引入无线传感器网络技术实现土壤碳通量的多点测量，以准确地评价区域的土壤碳通量指标。通过对动态开放箱法测定土壤碳通量的模型建立，提出了土壤碳通量的计算方法。设计了实现土壤碳通量测定的机械结构，并给出了相应的控制电路。实验结果表明，所设计的仪器与LI-8100的测量结果呈极显著相关，且能耗低，可满足野外的长期部署工作要求。     

The new European software guide for legal metrology: Basic principles

The European guideline WELMEC 7.2 “Software Guide (Measuring Instruments Directive 2004/22/EC)” has recently been adopted. It contains requirements and validation recommendations for software in measuring instruments subject to regulations in the Measuring Instruments Directive (MID).The definition of software requirements is derived from essential MID requirements and is based on type-independent configurations of instruments and on risk classes. The definition is completed by instrument-specific requirements.Configurations of measuring instruments are divided into basic configurations of measuring instruments and extended IT configurations. Furthermore, the requirements are differentiated according to risk classes introduced in the guide.The methodology developed is applicable not only to the originally intended category of instruments, namely measuring instruments regulated by the MID, but also to far more classes of measuring instruments.     

高温应变测试方法与测试系统开发

高温应变的测试往往是工程上的一个难点,高温会对传感器、测试仪器以及测试数据带来诸多的影响,需要采取有针对性的措施来保证测试方案的可行性和测试数据的准确性。通过实验分析高温对应变测试过程产生的各种影响,就高温应变计的选型和参数修正、高温条件下的温度补偿,以及测试数据的处理进行了详细的分析讨论。并针对这一过程开发了配套测试系统,通过实测某高温退火炉炉壁工作过程的应变情况,得到了准确的温度-应变曲线和炉壁的应力分布情况,在高炉的分析检测中取得了较好的效果,对一般的高温应变电测也具有很好的适用性。     

基于PC的直线度误差自动测量与评定系统

介绍了一种新颖的直线度误差自动测量系统———便携式激光准直仪。直线度误差评定软件设计时 ,考虑了直线度误差的两类测量方法和两种评定方法 ,具有运算速度快、适合直线度误差测量仪器多等特点     

一种高精度低成本A/D转换器的原理和实现

A／D转换器直接影响智能化仪表的测量精度和分辨率。提出了一种用软硬件结合方法实现的双积分A／D转换器。详细介绍了该转换器的工作原理、软件流程和电路的实现方法，通过自校零显著提高了A／D转换器的精度和稳定性，便于实现光电隔离，具有较高的性价比，在数显调节仪表中得到了广泛的应用。     

结冰云小水滴粒径测量设备综述

结冰云中小水滴粒径测量技术研究是开展飞机结冰试验研究的基础。概述了飞机飞行结冰气象条件特征；归纳了6种国外主要结冰云小水滴粒径测量设备，基于非光学技术的测量设备有：油片测量装置和旋转多圆柱测量仪，基于光学技术的测量设备有：前向散射分光测量仪、光学阵列测量仪、相位多普勒粒子分析仪和马尔文粒径测量仪。介绍了这些设备的原理、精度和应用环境；指出了国外应用于结冰风洞的小水滴粒径测量设备的发展动向；提出了国内自主发展此类测量设备的建议，目的是为我国结冰领域相关测量技术和设备研究提供参考。