【www.pindukj.com--技术合同】
篇一：测控技术与仪器专业英语翻译
5. Inheritance
In Figure 9.7, the classes SalesOrderCheclcPmt and SalesOrderCreditPmt are called subclasses of SalesOrder. The class SalesOrder is called the super class of SalesOrderCheckPmt and SalesOrderCreditPmt. The relationship between a class and its subclass (or superclass) is called generalization or specialization. Subclasses inherit attributes and operations from their class. A subclass has its own additional attributes and operations. For example, the class SalesOrderCreditPmt inherits the attributes order No, order Date, delivery Date, and order Terms and the methods calcTotal and changeDelivDate. In this case, the class SalesOrder is the generalized class, and SalesOrderCheckPrmt and SalesOrderCreditPrmt are the specialized classes.
6. Polymorphism
Earlier it was mentioned that a DVR and a DVD player that respond similarly but differently to the same message are polymorphic. Polymorphism means "having many forms". In the context of OQSAD, polymorphism means that the same message can invoke similar but different behavior. Thus, a message that invokes the operation calcTotalQ of a :SalesOrder object will result in the sales order total calculation; a message that invokes the operation calcTotaIQ of a PurchaseOrder object will result in a purchase order total calculation. The implementation of the operations in the respective classes will be different.
Foundations of the object model
Structured design methods evolved to guide developers who were trying to build complex systems using algorithms as their fundamental building blocks. Similarly, object-oriented design methods have evolved to help developers exploit the expressive power of object-based and object- oriented programming languages, using the class and object as basic building blocks. Foundations of the object model.
Actually, the object model has been influenced by a number of factors, not just object-oriented programming. The object model has proven to be a unifying concept in computer science, applicable not just to programming languages but also to the design of user interfaces, databases, and even computer architectures. The reason for this widespread appeal is simply that an object orientation helps us to cope with the complexity inherent in many different kinds of systems.
5。继承
在图9.7中，类SalesOrderCheclcPmt和SalesOrderCreditPmt被称为SalesOrder的子类。类SalesOrder被称为超类SalesOrderCheckPmt和SalesOrderCreditPmt的。一类和它的子类（或超类）之间的关系被称为泛化或专业。子类继承他们的阶级属性和操作。子类有它自己的附加属性和操作。例如，类SalesOrderCreditPmt继承属性订单号，订单日期，发货日期和订单术语和方法calcTotal和changeDelivDate。在这种情况下，类SalesOrder是广义类，并SalesOrderCheckPrmt
和SalesOrderCreditPrmt是专门的类。
6.多态性
早些时候有人提到，DVR和DVD播放器，以相同的消息作出回应，但类似的不同是多态。多态是指“有多种形式”。在OQSAD的上下文中，多态性是指同一消息可以调用类似，但不同的行为。因此，一条消息，调用的操作calcTotal：SalesOrder对象将导致销售订单总额计算;一个消息调用了一个采购订单对象的操作calcTotaL将导致采购订单总额计算。在各自的类中的操作的实现将是不同的。
对象模型的基础
结构化方法演变为指导开发谁试图建立使用的算法作为其基本构建模块的复杂系统。同样的，面向对象的设计方法已经发展到帮助开发人员利用基于对象和面向对象编程语言的表现力，使用类和对象的基本构建模块。对象模型的基础。
实际上，对象模型已经由许多因素的影响，而不是仅仅面向对象编程。对象模型已经被证明是一个统一概念在计算机科学中，适用不只是为了编程语言，但也给用户接口，数据库，甚至计算机体系结构设计。这样做的原因广泛的吸引力仅仅是一个面向对象的帮助我们以应付所固有的许多不同种类的系统的复杂性。
篇二：测控技术与仪器专业英语课文翻译
当然，有应用的个人电脑的所有者可能想比仅通过GPIB与各种设备的奇数，提供更高的性能。这种系统通常称为基于PC的工作站。在基于PC的工作站，仪器模块匹配性能和兼容性都聚集围绕PC电脑。基于PC的工作站允许来自多台仪器的数据迅速聚集，存储，作图，分析，并纳入一台PC机上的报告形式。这种类型的系统一般都放在一个制造商合作，以提高性能和涉及的仪器模块之间的合作。
There are, of course, applications for which the owner of a PC may want higher performance than that offered by the GPIB alone, with its odd assortment of devices. Such systems are generally referred to as PC-based workstations. In a PC-based workstation, instrument modules with matched performance and compatibility are clustered around a PC computer. The PC-based workstation allows data from multiple instruments to be rapidly gathered ,stored, graphed ,analyzed, and incorporated into report form on a single PC. Systems of this type are generally put together by one manufacturer to enhance performance and cooperation between the instrument modules involved.
一个基于PC的工作站的一个例子是惠普推出的PC仪器系统。 PC仪器是一系列的九个专用仪器模块，旨在通过一个专门的接口总线操作惠普触摸屏II个人电脑，IBM PC / XT / AT，AT＆T的电脑6300，或的HP Vectra PC。在PC的仪器提供仪器模块是一个50 MHz的数字示波器，一个12位数字 - 模拟转换器双通道，100 MHz的通用计数器，5 MHz的函数发生器，数字万用表。
An example of a PC-based workstation is the PC Instruments system introduced by Hewlett-Packard. PC Instruments are a series of nine dedicated instrument modules designed to operate over a dedicated interface bus by an HP Touchscreen II personal computer ,an IBM PC/XT/AT, an AT&T PC 6300, or an HP Vectra PC. Among the instrument modules available for PC Instruments are a 50-MHz digitizing oscilloscope, a 12-bit dual-channel digital-to-analog converter, a 100-MHz universal counter, a 5-MHz function generator, and a digital multimeter.
从仪器模块收集的测试数据直接送入电脑存储，显示和分析。该仪器模块本身有没有米，或显示自己的。所有输出，包括波形显示，通过电脑屏幕上，可同时显示多达八个不同的仪器输出。
Test data gathered from the instrument modules are fed directly to the PC for storage, display, and analysis. The instrument modules themselves have no meters or displays of their own. All outputs, including waveform displays, are through the PC screen, and up to eight different instrument outputs may be displayed simultaneously.
PC仪器通信与PC通过PC的仪器总线，或PCIB。 PCIB实现一个单一的接口卡插入到PC主板的扩展槽。每个PCIB接口卡支持多达8个仪器模块。安装到计算机中的第二个PCIB，允许为8个额外的仪器模块的支持。
PC Instruments communicates with the PC via the PC Instruments Bus, or PCIB. PCIB is implemented with a single interface card that plugs into one expansion slot of the PC motherboard. Each PCIB interface card supports up to eight instrument modules. Installing a second PCIB into the computer permits support for an eight additional instrument modules.
PCIB是独一无二的，它支持并行和串行通信（图1）。乍一看，两个通信信道，在一个单一的总线系统的想法似乎是多余的。然而，仔细分析，是实现节约成本和减少冗余。
The PCIB is unique in that it supports both parallel and serial communications (Figure 1). At first glance, the idea of having two communications channels in a single bus system appears to be redundant. On closer analysis, however, a cost saving is realized and the redundancy is reduced.
在一个典型的GPIB系统，有需要的输入和/或输出接地和计算机隔离，以使可浮动测量的仪器，如电压和电流米。隔离通常是providedby光隔离器的GPIB通信仪器中的数据串行方式使用并行到串行的转换。从仪器的数据，也必须通过使用光隔离串行到并行的转换器传递到GPIB。因此，每一个设备，需要隔离，还需要自己的一双光隔离器和相应的转换器。
In a typical GPIB system there are instruments, such as voltage and current meters, that require the inputs and/or outputs to be isolated from earth ground and the computer so that floating measurements can be made. The isolation is typically provided by optoisolators communicating the data from the GPIB side to the instrument in serial fashion using a parallel-to-serial converter. Data coming from the instrument likewise must pass to the GPIB through an optoisolator using a serial-to-parallel converter. Consequently, every device that requires isolation also requires its own pair of optical isolators and respective converters.
在PC仪器，测试仪器，可以选择之间的隔离的串行通信通道或更快，非隔离总线并
行通信。串行通道的并行到串行和串行到并行转换器被放置在接口卡，从而降低了系统成本，同时提高性能。
In PC Instruments, the test instrument may choose between an isolated serial communications channel or the faster, nonisolated parallel communications bus. The parallel-to-serial and serial-to-parallel converters for the serial channel are placed on the interface card ,thus reducing system cost while improving performance.
PCIB并行通信通道（图2）提供高速数据路径为文书，并不需要隔离。数据可传输速率最高可达100K字节/秒，受个人电脑主机的限制。并行通信通道包含一个8位数据路径，两条控制线，与相应的地面回报，是26芯的带状电缆连接个人电脑主机的模块化仪器的一部分。PCIB并行通信通道是向上兼容的GPIB，PC仪器最通用的系统。
The PCIB parallel communications channel (Figure 2) offers a high-speed data path for instruments that do not need isolation. Data can be transmitted at rates up to 100K bytes/second, subject to limitations of the host personal computer. The parallel communications channel consists of an 8-bit data path, two control lines, with appropriate ground returns, are part of the 26-conductor ribbon cable that connects the host personal computer to the modular instruments. The PCIB parallel communications channel is also upwardly compatible the GPIB, making PC Instruments a most versatile system.
PC仪器的最令人印象深刻的的方面之一是软前面板的系统软件，它提供了一个交互式图形用户手动控制仪器的机制。控制面板也可以直接调用eithej - DOS，BASIC，或任何其他语言，产生正确的反应，因此，贷款使用定制软件程序的计算机自动测试系统。
One of the most impressive aspects of PC Instruments is the soft front-panel system software, which provides an interactive graphics mechanism for the user to control instruments manually. The control panel can also be invoked directly from eithej- DOS, BASIC, or any other language that produces the correct response, thus lending the system to computer automated testing using customized software routines.
前面板软件模拟传统乐器堆放台式，允许用户同时观看所有的控制模块。它是一件简单的事TD选择一个新的仪器，利用简单的触摸屏，鼠标或键盘输入。
The front-panel software emulates a benchtop stacked with traditional instruments,allowing the user to control one module while viewing them all. It is a simple matter tdselect a new instrument using simple touch-screen, mouse, or keyboard inputs.
为每个已安装的仪器模块的软件是包含在所有时间内的主机电脑。每个测试模块的性能进行了优化个人表现及互动合作。数字示波器软件，例如，在当前的PC仪器行是最复杂的，是代表什么系统能够做到的事情。数字示波器]软件包分成五大功能：硬件设置，数据采集和显示，用户界面，测量，并控制。
The software for each installed instrument module is contained within the host computer at all times. The performance of each test module has been optimized for both individual performance and interactive cooperation. The software for the digitizing oscilloscope，for example, is the most complex in the current PC Instruments line, and is representative of what the system is capable of doing. The digitizing oscilloscope] software package is broken into five major functions： hardware setup, data acquisition and display, user interface，measurements, and program control.
硬件设置设置纵向和横向的敏感性，延迟timip耦合输入，采集模式，并触发配置示波器模量被调用时，安装说明在PCIB发送执行示波器modufl。
The hardware setup sets the vertical and horizontal sensitivities，delay timip coupling input，acquisition mode，and trigger configuration for the oscilloscope moduli When invoked，the setup instructions are sent over the PCIB to the oscilloscope modufl for execution.
数据采集包括以下测量过程，从示波器模块读取一个251字节的数据字符串。根据上述过程中所描述的硬件设置缩放的数据。用户使用前面板的图形，每个屏幕上的设置可能会被修改。因此，在数据显示的变化可飞。
Data acquisition consists of reading a 251-byte data string from the oscilloscope module following a measurement procedure. The data is scaled according to the hardware settings described in the procedure above. The settings may be modified by the user using the front-panel graphics that are available on every screen. Consequently, change in the display of the data can be made on the fly.
测量包包括控制电压和时间标记和自动参数测量上升时间，下降时间的波形分析?时期，频率，脉冲宽度，过冲，前冲，峰 - 峰值电压。这些测量的基础上的251字节的数据从示波器模块的字符串使用直方图来确定的绝对和相对maximum9 minitnum，和个百分点，以及上升沿和下降沿的位置，统计分析。因为统计学的数据显示，而不是身体，它也受到tosoftware处理在大致相同的方式，信号处理与RC Flectronics是IS - 16 COMPUTERSCOPE在本章开头所述。
The measurement package includes control of voltage and time markers and waveform analysis for automatic parametric measurements of rise time，fall time? period, frequency, pulse width, overshoot, preshoot，and peak-to-peak voltage. These measurements are based on a statistical analysis of the 251-byte data string from the oscilloscope module, using a histogram to determine the absolute and relative maximum9 minitnum, and percentage points, as well as the location of rising and falling edges. Because the data is displayed statistically，not physically，it is also subject tosoftware processing in much the same way that signal processing was done with the R C Flectronics IS-16 COMPUTERSCOPE described at the beginning of this chapter.
个人电脑工具软件还允许通过电脑仪器之间的数据交换。例如，在示波器显示屏上看到的变化，可以调整使用软件的反馈循环，函数发生器，继电器执行器等，一个应用程序可能预期随频率变化。通过监测被测设备的输出电压，使用示波器，可自动补偿信号波动的数据字符串和软件处理，函数发生器的输出电平调整。
The PC Instruments software also allows for data exchange between instruments via the computer. For example，changes seen on the oscilloscope display can be adjusted using software feedback loops to the function generator, relay actuator, etc. One application may be expected to vary with frequency. By monitoring the output voltage of the device under test, using the oscilloscope，s data string and software processing, adjustment to the output level of the function generator can be made to automatically compensate for signal fluctuations
基于PC的工作站，不论是作为一个像惠普PC从GPIB元件组装的仪器系统购买，也非常适用于自动化测试环境。自动测试系统，自动测试设备（ATE）组装，计算机与数字控制的激励和测量仪器接口
The PC-based workstation，whether purchased as a system like the Hewlett-Packard PC Instruments of assembled from GPIB components, also lends itself well to automated testing environments. Automated testing systems，assembled from automatic test equipment (ATE), are a result of the computer being interfaced with digitally controlled stimulus and measurement instrumentation.
ATE正在迅速取代台式设置，手动控制，使测量的仪器。一旦启动，ATE可以继续在没有外界干预其运作，可以在几秒钟内数以千计的参数测试。 ATE的记录测试数据时，不犯错误，不妥协的测试，不会忘记测试，不累。因此，ATE极大地提高了吞吐量和测量精度。它甚至可以纠正自己的错误，其测量结果比较已知的标准和补偿的区别。
ATE is quickly replacing the benchtop setups of instrumentation that were manually controlled to make measurements. Once started, ATE can continue its operation with no outside intervention and can test thousands of parameters in seconds. ATE does not make mistakes when recording test data, does not compromise a test， does not forget tests, and does not get tired. Consequently, ATE dramatically improves throughput and measurement accuracy. It can even correct its own errors by comparing its measurement results to a known standard and compensating for the difference.
可分为三大类：台式，专用，通用ATE测试系统。生产半导体和大型电子系统，专用自动测试设备是必要的，尽管沉重，投资。但是，成千上万的小系统和子系统制造商，成本更低的台式PC为基础的工作站是更好的解决。
ATE test system may be divided into three classes：benchtop, dedicated, and general-purpose. For manufactures of semiconductors and large electronics systems, dedicated automatic test equipment is a necessary, albeit hefty, investment. But for thousands of small systems and subsystems manufacturers, the less costly benchtop PC-based workstation is the better solution.
灵活的ATE系统通常由加入由IEEE - 488或RS - 232总线，以纾缓的不兼容问题，可以发生在来自不同供应商的连接部分的现成文书。这种方法的主要优点是，它可以很容易地为多种测试应用程序重新配置，只需更换一个另一台仪器。
A flexible ATE system usually consists of off-the-shelf instruments joined by an IEEE-488 or RS-232 bus to relieve the incompatibility problem that can occur in linking parts from different vendors. A major advantage of this approach is that it can easily be reconfigured for a variety of test applications by simply swapping one instrument for another.
灵活的ATE测试中，是没有操作员干预的应用一般是完全可编程。尽管如此，其成分也应该允许操作员干预或手动操作时的情况使然。例如，手动操作时，仪器具有功能关闭行轻微的测试任务，为维护或故障排除目的，或系统测试软件的编写和调试是可取的。
Flexible ATE is generally fully programmable for applications in which testing is to be done with no operator intervention. Nonetheless，its components should also allow for operator intervention or manual operation when the situation so dictates. For example，manual operation is desirable when an instrument has to function off-line for maintenance or troubleshooting purposes, for minor testing tasks, or for writing and debugging the system test software.
到ATE的一个缺点是在编写软件所产生的费用。因为编写软件可配置ATE系统时，最大的单一任务，必须谨慎，在选择编程语言和程序结构。有人估计，软件开发成本可以运行系统成本的90％。一般而言，ATE系统将耗资4至7倍多相当于手动工具。
A drawback to ATE is the expense incurred in writing the software. Because writing software can be the largest single task when configuring an ATE system, care must be exercised in the programming language selected and the structuring of the program. In some estimates, the cost of software development can run 90 percent of the cost of the system. Generally, an ATE system will cost four to seven times more than equivalent manual instrument.
篇三：测控技术与仪器专业英语
Unit 1Definition of Measurement and Measurement Theory
定义的测量方法和测量理论
1. Definition of Measurement测量的定义
A possible operational description of the term measurement which agrees with our intuition is the following :“measurement is the acquisition of information ”;the
aspect of gathering information is one of the most essential aspects of measurement ;measurement are conducted to learn about the object of
measurement ;the measurand .This means that a measurement must be descriptive with regard to that state or that phenomenon in the world around us which we are measuring .一个可能的操作描述这个术语的同意,我们凭直觉测量是下列的“测量信息获取”,采集信息的方面是最重要的方面进行测量,计量了解测量的对象,进行测量。这意味着一个测量必须描述对于这种状态或这一现象在我们周围的世界我们衡量。There must be a relationship between this state or phenomenon and the measurement result .Although the aspect of acquiring information is elementary ,it is merely a necessary and not a sufficient aspect of measurement :when one reads a textbook ,one gathers information ,but one does not perform a measurement.必须有一个关系状态或现象和测量结果信息获取的角度,即使是基础,那只是一个必要的和非充分方面的测量:当一个人阅读教科书,一个收集信息,但是一个人不能进行测量。A second aspect of measurement is that it must be selective .It may only provide information about what we wish to measure (the measurand) and not about any other of the many states or phenomena around us .测量的第二个方面,它必须被选择,只能提供有关我们所希望的那样进行测量测量),而不是对任何其他的许多州或现象在我们身边。This aspect too is a necessary but not sufficient aspect of measurement .Admiring a painting inside an otherwise empty room will provide information about only the painting ,but does not constitute a measurement.这相位也是必须的,但并非任何足够的测量方面.Admiring一幅画在一个否则
空房间会提供信息,只有这幅画作,但不构成测量。
A third and necessary aspect of measurement is that it must be objective .The outcome of the measurement must be independent of an arbitrary observer .Each observer must extract the same information from the measurement and must come to the same conclusion .This, however ,is almost impossible for an observer who uses only his/her senses .Observations made with our senses are highly subjective .Our sense of temperature ,for example , depends strongly on any sensation of hot or cold preceding the measurement .第三个和必要的方面,它必须被测量,结果客观测量必须独立于任意观测器提取每观察者必须之测相同的信息,必须得出了相同的结论。这,然而,几乎不可能一个观察人士只使用他/她的感官感觉是我们.Observations我们高度主观的感觉,例如,取决于温度有任何感觉热或冷的measuremen前。This is demonstrated by trying to determine the temperature of a jug of water by hand .If the hand is first dipped in cold water, the water in the jug will feel relatively warm ,whereas if the hand is first dipped in warm water ,the water in the jug will feel relatively cold. Besides the subjectivity of our observation ,we human observers are also handicapped by the fact that there are many states or phenomena in the real world around us which we cannot
observe at all (e.g. magnetic fields) .or only poorly (e.g. extremely low
temperatures or high-speed movement) .In order to guarantee objectivity of a measurement we must therefore use artefacts (tools or instruments).这是证明了在调查里面的水的温度用手,如果手先用冷水浸泡到瓶子里的水会感到相对的温暖,而若手第一蘸温水、水到瓶子里会感觉比较冷。除了我们观察的主体性,我们人类的观察家们也不识字而事实有许多州或者现象在现实世界中,我们不能遵守我们周围磁场(如只poorl支)。The task of these instruments is to convert the state or phenomenon under observation into a different state or phenomenon that cannot be misinterpreted by an observer .In other words, the instrument converts the initial observation into a representation that all observers can observe and will agree on .这些仪器的任务是把国家或现象观察进入一种不同的国家或现象,不能被误解被观察者。换句话说,仪器将最初的观察到任何观
测者都表示会同意能封锁。For the measurement instrument’s
output ,therefore ,objectively observable output such as numbers on an
alpha-numerical display should be used rather than subjective assessment of such things as colour ,etc.. Designing such instruments ,which are referred to as measurement systems ,is the field of (measurement) instrumentation.用来测量仪器的输出,因此,客观观察的输出如数字显示alpha-numerical应使用而不是主观评价诸如色彩,等。设计这样的仪器都被称为量测系统,域(计量仪表。In the following ,we will define
measurement as the acquisition of information in the form of measurement results ,concerning characteristics ,states or phenomena (the measurand )of the
world that surrounds us, observed with the aid of measurement systems
(instruments ).The measurement system in this context must guarantee the required descriptiveness ,the selectivity and the objectivity of the measurement .在下面,我们将定义测量信息获取的测量结果不确定度的形式,对特征、国家或现象(世界上进行测量
在我们周遭,观察与援助的测量系统(仪器测量系统,在此背景下,必须保证所需的
descriptiveness,选择性和客观性的测量。We can distinguish two types of
information :information on the state ,structure or nature of a certain
characteristic ,so-called structural information ,and information on the magnitude,
amplitude or intensity of a certain characteristic ,so-called metric
information .The acquisition of structural information is called a qualitative measurement ,the acquisition of metric information is called a quantitative measurement .If the nature of the characteristic to be measured is not (yet) known ,it must be determined first by means of a qualitative measurement .This can then be followed by a quantitative measurement of the magnitude of the respective characteristic.我们能区分出两种类型的信息:信息对国家、结构或自然的一个特定的特点,所谓的结构信息、信息在大小、振幅或强度一定的特点,所谓的度量信息,获得结构信息被称为定性测量、获取信息度量称为定量测量。如果性质测量特点,还不知道的,它必须实现
2 Measurement Theory
In the previous section we have seen that measurements from the essential link between the empirical world and our theoretical ,abstract image of the world .This concept forms the basis of a theory of measurement .In this theory a measurement
result is considered to be a representation of the actual empirical
quantity .Measurement theory treats measurements as a mapping of elements of a source set belonging to the empirical domain space (see Fig .1.1 ) onto the elements of an image (or outcome ) set which is part of the abstract range (or image ) space .在上一节中我们已经看到,测量来自必要的联系,我们的经验世界理论、抽象形象的世界。这观的基础上测量理论。理论,讨论了测量结果被认为是代表了实际经验数量.Measurement理论对测量数据元素的地图源设置属于实证域空间(见图.1.1的元素上一幅图像(whi)或结果。The quantity to be measured (the measurand ) is an element of the source set .For instance ,in the electrical domain we measure electrical current (source set ) but only within a certain range of magnitude (elements). The result of the measurement process is abstract ;it forms an element of the image set in the abstract range space . 测量的量进行测量)是一种元素的源设置情况,因为在电领域受到我们测量电流)但只有在一定范围内的大小(原理)。测量过程的结果是抽象的,它形成了一个元素的抽象的图像范围空间。For example, the magnitude of the electricalcurrent to be measured in the above example is (by measurement ) assigned a certain number (element ) out of the set of real numbers (image set ).例如,电流的大小来衡量在上面的例子中(通过测量)分配一定数量(元素)从套真实数字(图像)。In other words ,the elements of the source set are empirical characteristics of States and phenomena of the world around us ; the elements of the image set are symbols of the abstract image set of symbols . The symbols can be numbers (quantitative measurements ) but can also be ,for example ,names (quantitative measurements ).换句话说,元素的来源是实证特点设置状态和我们周围的世界的现象;要素的图像的抽象符号图像集象徵。符号可以是数字(定量测量),还可以为例,定量测量)名字。Restricting the definition of measurement further , measurement theory states that measurement is the mapping of elements from an empirical source set onto elements of an abstract image set according to a particular transformation function . The transformation function consists of the assignment algorithms , results or procedures that define the representation of empirical quantities by abstract symbols .限制测量的定义进一步、测量理论认为测量测绘的要素,从实证源固定在抽象的图像元素根据特定的转换功能。转换函数由任务的算法,结果或程序确定表示的实证数量由抽象符号。In practice the assignment algorithm , rule or procedure is implemented by the employed measurement system. The measurement system therefore determines the representation . As stated earlier , this representation must be done in a description ,objective and selective way . Thus , the image set must consist of elements (measurement outcomes ) which are abstract symbols with a unique meaning about which , by definition , all observers agree .在实践中,分派算法、规则、程序是由受雇测量系统实施。测量系统因此决定表示。如前所述,这些表示都被做以描述、客观、有选择的。因此,对图像集必须包含的元素(测量结果),有抽象符号具有独特的意义,被定义,所有的观察家们也一致。A measurement must be descriptive .In measurement theory this is described in terms of set theory :the relations that exist between the elements of the source set must be maintained under the transformation in the image set ,for example ,’larger than ’, ‘equal to ’
and ‘smaller than ’.一个测量必须描述了在测量理论从集理论存在的关系成分之间的源设置下必须保持对图像集的转型中,例如,“比”、“等于'和'小于”。The set of relations between the elements of the source set is referred to as the relational system (of the source set ).之间的关系的来源的元素将被称为关联系统(的源套)。This empirical relational system determines the structure of the source set . Likewise ,an abstract relational system determines the structure of the image set (for instance ,the set
of relational that apply to the set of integer numbers ). A measurement
(representation ) is now called descriptive if the relational system or structure of the empirical source set is invariant under the transformation (measurement ) . 本实证关系系统确定源的结构。同样地,抽象的关系系统确定图像的结构(例如,关系,适用于整数的数字)。测量(表示)现在称为描述性如果关系系统或结构变化设置经验主义来源转换(下测量)。The measurement only represents that which is measured if the two relational systems are identical ; otherwise information is lost in the mapping . An example is measuring with a very low resolution ; two different current magnitudes are mapped onto the same outcome , and are indistinguishable from each other .测量测量只代表了,如果两个关系系统都是相同的,否则资料遗失在映射。一个例子是测量一
个非常低分辨率;两个不同电流大小映射到相同的结果,与对方。
Unit2 Measurement of Physical Quantity物理量测量
The physical quantities listed bellow are often used in test and measurement technology .The first 2 are commonly called as electrical quantities and the other
are commonly called as electrical
parameters .
Usually the sensors receive the information of quantities under measurement (QUM) and convert it into variation of electrical parameters or electrical potential, which will normally be conditioned ,and then converted into the electrical quantities ,specially the current ,and sent to the A/D converters .如下所示的物理量的常被用于测试和测量技术,第2通常被称为电子数量和其他通常被称为电气参数。
通常传感器接收信息清单QUM测量(下),把它转化成电气参数的变化或电气潜力,通常
会条件,然后转化为电气数量,特别是当前的众长老、就差人到A / D耐.
Electrical potential difference 电气电位差
The primary standard for electrical potential difference used to be provided by an electrochemical standard cell (the Weston standard cell ).The voltage of a Weston cell is approximately 1.01860 V at 20`C,with an inaccuracy of 3X10^-6 under optimal conditions. Optimal conditions means a variation of temperature less than 10^-3 K, no load, no vibrations or jolting . The cell must remain in an upright position.
A Weston standard cell has a very long thermal after-effect. After the cell has been heated to 30`C it can take 6 months before it is totally stable within 0.3u V of the original value at 20degrees .Furthermore ,a Weston cell will age , resulting in an increase in the internal resistance (R1~500-1000欧)，and a small decrease of a few uV in the output voltage (during the first years ).电气的基本标准的用于电位差由电化学标准电池的(韦斯顿标准电池电压成),大约1.01860韦斯顿细胞是五世在20'C的精度,在优化的分析条件下,3X10 - ^。最优性条件温度的变化是指小于10 ^ - 3钾、空载,没有振动或震动。细胞必须保持在一个垂直位置。一个韦斯顿标准电池的有很长的热
after-effect。在细胞被加热到3.
Electrical current 电流
lectrical current is standardized by measurement with an instrument called a ‘current balance’. This device measures the electromagnetic force between two current carrying coils (one fixed ,one moving ) by balancing it with the force of gravity ,acting on a known mass . The force between the coils is given by F=I^2dM/dx , in which M is the known mutual induction of the coils and x is the known distance between them . The differential quotient dM/dx is determined by known geometry of the coils .通过测量规范激励激光器阻抗电流被称为“用铁器当期资产”。这种装置措施电磁力在两个电流负载线圈(一个固定的,一个运动)平衡与重力的作用下,行动在一个已知的质量。线圈间的力进行女=我^ 2dM / dx,,M是已知的相互感应的线圈与x是已知的间距。
鉴别商dM /远程接收由已知的几何学的线圈。
Electrical resistance 电阻
Standards of electrical resistance are resistors wound of special alloy wire giving a minimal temperature effect .An example of such an alloy is evanohm , consisting of 74% nickel ,20%chromium and 6%aluminium and iron . This alloy is frequently used for high resistance standards (10kQ). For low resistance values (1Q) manganine (86%Cu ,12%Mn ,2%Ni ) or constantan (54%Cu ,45%Ni ,1%Mn ) is often used .Higher –order resistance standards are kept at very accurately stabilised temperature by thermostats .标准是电阻的特殊合金线电阻伤口给一个最小的温度效应的代表.An evanohm是一种合金,由74%镍、20%chromium和6%aluminium与铁。这种合金是经常用于高阻标准(10kQ)。低阻值(第manganine(86%Cu,12%Mn),2%Ni)或constantan(54%Cu,45%Ni,1%Mn)常常
被.Higher -order电阻标准保持非常准确稳定温度温控器。
Capacitance 电容
It is possible to construct a capacitor from four coaxial cylinders , whose capacitance only depends on the length of the cylinders . Such a capacitor is particularly suitable as a standard of capacitance , since only the length has to be determined accurately . With the aid of optical interferometry this can be done extremely accurately . These so-called Thompson-Lampard cylinder capacitors can achieve an inaccuracy of less than 10^-8. 它可以构建电容器的从四个同轴钢瓶,电容仅凭长度的汽缸。这样的电容器是特别适合标准的电容,因为只有长度必须提供准确的参数。与援助的光学干涉技术能够依此作成,非常准确。这些所谓的Thompson-Lampard缸电容可以达到不小于10 ^ - 8。 A disadvantage ,however ,is the fact that the capacitance is