测控技术与仪器专业英语课文翻译单元2
测控技术与仪器专业英语 Unit 2
14
2 M- of non-physical quantities
– It is essential to the nature of an organism or an 2.7 organization that they maintain (social, cultural, political) interactions with their environment. – 保持与周围环境的交互对于生命体或组织的性质是非常必 要的。 – For this reason, it is usually not possible to perform an 2.8 isolated measurement in the same way we can with inanimate things (putting in a thermostat, hooking up to a fixed supply voltage, etc. )
7
1 Measurement of Physical Quantity
• Electrical potential difference
– The primary standard for electrical potential difference used to be provided by an electrochemical standard cell (the Weston standard cell).
2 M- of non-physical quantities
– With non-physical measurements, however, the 3.3
《测控技术与仪器专业英语》张凤登UNIT-2-发电和输变电-参考译文及练习答案
·5·UNIT 2 发电和输变电参考译文2.1 电磁感应如将一根导电棒通过磁场，每个自由电子由于通过磁场的运动产生一个力。
如运动的方向使作用在电子上的部分力平行于导体，电子将沿着导体运动。
电子的运动直到它受到由于导体切割磁场运动的力和静电力平衡为止。
这种静电力是因为电子聚集在导体的一端，而另一端缺少电子而引起的。
当运动持续进行时，在导体中形成的这样一个电场，使得导体两端之间存在一个电位差。
一旦运动停止，静电力将导致电子返回其正常分布。
从磁感应强度（磁通密度）B 的定义看，在电荷q 通过磁场的运动中，电荷所受到的力由方程（2-1）得到，q sin Bqv F = （2-1）式中，力F 和由电磁场方向确定的平面垂直，vsinθ是垂直于磁场方向的速度分量，B 的单位是韦伯/米2（webers/m 2），q 的单位是库仑，v 的单位是米/秒（meters/sec ），F 的单位是牛顿。
由这个力产生的电场强度E ，即每单位正电荷受力的大小和方向。
电场强度等于负的沿导体的电势梯度。
在动生电动势（emf ）中，电荷被认为是负的，这样等式（2-2）成立þýü=-=-=-=q e e q sin /sin )/(Blv lBv q F E （2-2）这里，l 是导体垂直于磁场方向的长度，电动势ε的单位是伏。
不论电路是否有闭合，导体通过磁场时，这个电动势总是存在的。
只有当电路闭合，并且电路的其余部分不以和导体运动完全相同的方式通过磁场时，电流才会建立。
例如，导体沿着连接在一起静止轨道滑行，闭环电路中会出现电流。
但是，如果在导体的两端和一根导线连接，导线和导体一起移动并通过磁场，导线中也会感应出一个与导体中大小相等的、和电路中现有的反向的电动势。
2.2 单相和三相交流电单相交流电压是由单相交流发电机产生或它可以通过三相交流电的两根电力线获得。
单相交流电有一根火线，一根中线。
测控技术与仪器专业英语阅读翻译
测控技术与仪器专业英语阅读翻译篇一：测控技术与仪器专业英语翻译5. InheritanceIn Figure , 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. PolymorphismEarlier 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 caninvoke 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 modelStructured 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 complexityinherent in many different kinds of systems.5。
测控技术与仪器类外文翻译、中英文翻译
过滤阴极真空电弧镀膜技术所制得氧化铝薄膜的结构和特性摘要：通过过滤阴极真空电弧镀膜技术制备氧化铝薄膜时，其内部结构、组成、形态、光学和机械性能被详尽的描述，这些都与制备时氧气的流量有关。
薄膜结构、组成、形态和性能都是很重要的，随着氧气流量的增加，薄膜的结构也由非晶体经过一系列变化到单晶体，随着O/Zr原子比率的增加和Z离子由低氧化作用的状态转化为Zr4+再一次形成非晶体。
形成这样的结构是由于其内部结构的变化而引起的，并且影响其形态和机械性能，以致这种非晶体薄膜表面有一些小簇，其光滑程度就像低硬度的多晶体薄膜。
当反射指数和系数相对接近最大值时，在发射率和光学带宽随着O/Zr比增加时，薄膜的组成来决其光学性能而非其密度。
1.说明在大气压力下由于三种不同温度有多种不同靶形态结构，单晶体时低于1170O C，四面体时为1170-2370O C，2370O C为立方体，知道2680O C时形成金属。
Zr有很高的反射指数，大光学带宽间距，和很低的光损失及在0.3-8范围内高透明度,所以被广泛的应用于光学领域。
此外，Zr具有很高的电介质，低泄露量等特点，最有可能代替做电解质的晶体管。
进而，由于Zr很低的传热性，它成为了装置中隔热层的首选。
Z其他的特性如：高硬度、高抗氧性也使其成为机械材料中的热门。
至今为止，已经有很多制备Z的方法，例如反应磁控溅射，离子辅助反应溅射，化学气相沉积等。
薄膜特性的优劣取决于制备过程及其参数。
过滤阴极真空电子弧镀膜技术，在低电压和高电流状态下工作。
通过磁性机械过滤器来防止微粒从阴极发射。
它提供了一种具有很高能量的沉积离子源，远大于相应的热蒸发和磁控溅射。
能有效去处宏观无用微粒，很明显能提高薄膜质量并拓展其应用。
固有的高能量提高薄膜的附着性和密度。
由于能力是离子辅助沉积中最重要的参数，这种制备的方法已经有了一些应用，已经应用于在高热平衡和高SP3状态下碳薄膜的制备，还合成了一些金属氧化物的薄膜。
测控技术与仪器专业英语翻译 殷虹 河北工业大学适用
测控专业英语翻译Unit1Measurement,ControlandInstrumentation Instrumentati on is defined as the art and science of measurement and control.Instrumentation engineers are responsible for controlling a whole system like a power plant.译为：仪器可定义为测量和控制的艺术和科学。
仪器工程师负责控制整个系统，比如一个电厂。
An instrument is a device that measures and/or regulates process variables such as flow, temperature, level, or pressure. Instruments include many varied contrivances that can be assimple as valves and transmitters, and as complex as analyzers.译为：仪器是一种用来测量和/或调节过程变量（如流量、温度、液位或压力）的装置。
仪器包括许多不同的设备，可以像阀和变送器那样简单，也可以像分析仪那样复杂。
Instruments often comprise control systems of varied processes such as refineries, factories,and vehicles. The control of processes is one of the main branches of applied instrumentation. Instrumentation can also refer to handheld devices that measure some desired variable.Diverse handheld instrumentation is common in laboratories, but can be found in thehousehold as well. For example, a smoke detector is a common instrument found in mostwestern homes.译为：仪器通常由如精炼厂、工厂和车辆这些不同流程的控制系统组成。
测控技术与仪器专业英语unit
全句译为：然而，供应电压从5V衰减到3.3V甚至更低， 以及系统中多种电压形式的出现，并不只是对最智能的传 感器提出的考验。
Separate integrated circuits (ICs) are available to handle the variety of voltages and resolve the problem, but they add to system and sensor complexity. 译为：单独的集成电路（ICs）可用来处理各种不同的电压 并解决问题，但它们增加了系统和传感器的复杂ors
Some of those same semiconductor manufacturers are actively working on smarter silicon devices for the input and output sides of the control system as well. The term microelectromechanical system (MEMS)（微机电系统） is used to describe a structure created with semiconductor manufacturing processes for sensors and actuators.
译为：在今天几乎一切的技术领域都将智能一词作为 其前缀的候选。智能传感器这一术语是在20世纪80年代 中期出现的，从那以后，一些设备已被称之为智能传感器。
3
Unit3 Smart Sensors
The intelligence required by such devices is available from microcontroller unit (MCU), digital signal processor (DSP), and application-specific integrated circuit (ASIC) technologies developed by several semiconductor manufacturers.
测控专业英语韩建国课文翻译
CHAPTER.1Introduction to Measurement Unit1Definition of Measurement and Measurement Theory1.Definition of Measurment一个可能的操作的描述术语,同意我们的直觉测量是以下,测量是获取信息”,外表的信息收集是其中最重要的方面进行测量,测量学习对象的测量,测量。
这意味着一个测量必须描述关于该状态,或者在世界的现象——围绕我们,我们是测量。
必须有一个关系状态或现象和测量的结果。
尽管方面获得信息是小学它仅仅是一个必要的和非充分方面的测量:当一个人阅读一本教科书、一个收集信息,但是一个不执行一个测量。
第二个方面是,它的测量须有选择性的。
它可能只提供有关我们希望测量(测量),而不是任何其他的许多州或现象在我们周围。
这方面也是必要的,但不足以方面的测量。
欣赏一幅画在一个空荡荡的房间将提供信息只有这幅画,但不构成测量。
第三个和必要的方面在于它必须测量的目的。
测量的结果必须独立于一个任意的观察者。
每个观察者必须提取相同的信息从测量和必须得出了同样的结论。
然而,这几乎是不可能的,一个观察者只使用他/她的感官,观察和我们的感官是高度主观的。
我们的意义上的温度,例如,很大程度上取决于任何感觉热或冷前测量。
这是证明了试图确定一壶水温度用手。
如果手首先浸泡在冷水,壶里的水会觉得相对温暖的手,而如果是第一个浸泡在温水,水在壶会觉得相对冷。
除了我们的观察”知道,我们人类观察员也残疾的事实有许多州或现象在现实世界的我们,我们不能观察(e.g.磁场),或者只差(e、g、极低的温度下或高速运动)。
为了保证测量的客观性因此,我们必须使用文物(工具或工具)。
这些工具的任务是把国家或现象受到观察到一个不同的状态或现象,不能被误解的观察者。
换句话说,该仪器将初始观察到一个表示,所有的观察者可以观察并将同意。
为测量仪器的输出,因此*客观可观察到的输出如数字应该使用一个字母数字显示,而不是主观评估诸如颜色等。
测控技术与仪器专业英语翻译
Selected from “Introduction to Control System technology , 4th Ed. , by Robert N. Bateson, Macmillan Publishing Co., 1933”. 选自“控制系统技术，第四版的介绍，罗伯特N.贝特森，麦克米兰出版有限公司，1933。
• 测量变量（CM）是衡量价值的控制变量。这是输出的测 量手段和通常不同于实际的控制变量的一小部分。
• The error (E) is the difference between the setpoint and the measured value of the controlled variable . It is computed according to the equation E=SP-.
控制变量（C）是过程的输出变量，用来出变量,它能很好地衡量 产品的质量。最常见的控制变量有位置、速度、温度、压 力和流量水平。
•
•
The set point (SP) is the desired value of the controlled variable.
6.Variable Name（变量名称）
•
The controlled variable (C) is the process output variable that is to controlled. In a process control system, the controlled variable is usually an output variable that s a good measure of the quality of the product. The most common controlled variables are position, velocity, temperature, pressure level and flow rate.
最新-测控技术与仪器专业英语阅读翻译 精品
测控技术与仪器专业英语阅读翻译篇一：测控技术与仪器专业英语课后阅读翻译(1,5~10)第1章课后,,,???,,,?,,??,?,,(1950),,??,,??,;,,,(,),,,,,,=(2),,,(),水下声波信号在声纳操作过程中，操作员经常需要对受噪声干扰的信号进行检波。
干扰信号可能来自操作员发出信号的反射波或者外部声源的信号。
这两种类型的干扰对主动声纳和被动声纳都会造成很大影响。
类似的情况在雷达监测、工程类和图像类专业的基本原理都会涉及到。
当你想到信号检测时有多种方法，那么定义一个术语来表示特殊情况便是可行的。
当问题的答案是“当前有一个还是一个多个信号？”时，检波一词将被使用。
一个系统被设计来为这种问题提供答案--无论是必然性还是偶然性，这就需要谈及假设检验；当一个信号反复出现的情况下，许多系统只被设计提供两个答案：“是的，当前有一个信号”或“不，当前没有信号”。
力图将信号分类会使问题复杂化，因为后者的结论将涉及到目标分类。
一般来说，一种检波仪器只被设计在固定的类型和参数下工作，不容易被改变，例如时间积分检波电路和光学检测的辉光示波管。
当出现不明信号时，观察者在拒绝或接收信号方面有所迟疑。
在这种情况下，操作员会有种感觉如果检波电路或者示波管能够延长时间那么他就能下结论该信号是否存在。
沃尔德（1950）在他的检波理论系统阐述了这种直觉。
如果（一个检测检测方法）能够主动去改变时间间隔并在接收系统里储存数据以便达到确定的某一水平，这就是顺序检测。
一般不仅能够确定信号存在与否，而且还能确定一个或多个与信号关联的参数。
在还原完整波形时我们所感兴趣的参数在各简单分量间有很大差别，例如信号的到达时间和相位。
当一个系统被设计来提取一个或多个信号参数时，这就是信号抽取。
信号一词并没有明确的定义，只是在读者对它有直观了解时的一种假设。
有些较为详细的解释为了对信号一词进定义可能导致是比较主观的或者狭隘与所应用的条件。
测控技术与仪器专业英语UNIT-2-Power Generation and Transmission
框架尺寸相当时，三相交流电机的功率值比单相交流电机大50%。
2.3 Further Reading
Transformers 变压器
New Words and Phrases
transformer
n.
electromagnetism n.
autotransformer n.
substation
n.
classification
magnetic coupling or mutual inductance 磁耦合或互感
expanding and collapsing of …
…的增强和减弱
powered metal core transformers
强磁化金属芯变压器
step-up
升压的
step-down
降压的
inverse ratio
sine
n.
正弦
transmit
v.
transfer, 输送
pulsate
v.
脉动
cylinder ['silində]
n.
汽缸，气缸，圆柱体
rating ['reitiŋ]
n.
额定值，标称值；级别
测控技术与仪器专业英语单词翻译
测控技术与仪器专业英语单词翻译If a measurement is slightly off the mark,we have the tendency to compensate for the error by allowing the recorded eeading to creep closer to our perceived impression of the true value.如果测量值有轻微的偏差，我们综合室倾向于补偿误差将记录值向感觉的真值靠拢。
更糟的是事实上两次测量中仪器本身不会一直指向相同的位置，由于指针的移动的。
Aggravating the situation is the fact that the meter itself does not always register identical values the same way twice,depending on which way the pointer happens to be moving. .大多数的误差来自视差，即观察仪器指针的角度不垂直造成的视差，即使我们已经解释了这种生理特性，却还是想从自身逃避责任While the main gate is open,the conditioned input signal pulses are passer through to the counting register,where they are tallied and then scaled for output by the display circuitry.当主控门打开时，经过转换的输入脉冲通过其进入计数寄存器，并在此统计，然后通过读书屏输出。
Because the frequency counter must accommodate a wide range of input signals,with vary degrees of voltage,noise component,and DCoffset,the input must pass through many conditioning circuits before it is fully conditioned.由于频率计数器必须提供一个宽范围的输入信号，使之能够适用于不同伏特，噪声成分和直流偏移，所以输入信号在充分变换前必须经过许多转换电路。
测控技术与仪器专业英语课文以及单词
? One can measure thickness on many scales .The galaxy is sphick.. 你可以测量厚度,在许多尺度螺旋星系的约100 Em(1020m磁盘)深
? 3.Distance measurement 3。距离测量
? The tools and techniques of distance measurement are possibly one of humankind's longest-running inventive pursuits .This chapter concerns itself with methods to measure a relatively small segment of this range-from centimeters to kilometers .Even within this limited segment ,it would hardly be possible to list ,much less describe ,all of the distance measurement approaches that have been devised .Nevertheless ,the small sampling of technologies that are covered here should be of help to a broad range of readers.
? The altitude information at air traffic control (ATC) centers is based on pressure altitude measurement that the aircraft transponder system sends after it receives an appropriate interrogation——known as mode C interrogation——transmitted by a secondary surveillance radar. Actually, the altitude information is an atmospheric pressure measurement transformed to altitude indication through a formula expressing the pressure/altitude relationship. When a flight level is cleared for an aircraft, it actually means that the pilot must keep flying on an isobaric surface. However, the altimetry system may present systematic errors (biases) that are different for each airplane, and that significantly affect safety. Thus, the altimetry system performance as well as the aircraft height keeping performance must be monitored by an independent radar or satellite system. 信息的高度,在空中交通管制中心(ATC)根据压高度测量,飞机的应答机系统发给后都把它珍藏一个适当的审讯——被称为模式C讯问——通过二级监视雷达。实际上,高度的大气压力测量信息转化为高度通过公式显示表达压力/高度的关系。当一个飞行高度是允许飞机时,实际上就意味着飞行员必须不停地飞在一个isobaric表面。然而,altimetry系统系统误差可能出现偏差)(飞机的不同而有所区别,明显影响安全。因此,altimetry系统性能以及飞机高度保持性能均须由独立的雷达或卫星电视系统
测控技术与仪器专业英语全书翻译
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
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
测控技术与仪器专业英语教程(第2版)课后答案 英译汉
第五章课后A random erroris due to acontrolled，large number of independent small effects that cannothe identified orit is a statistical quantity. As such，iteach replication of the observations. If a large number of readings iswill vary for the same quantity.the scatter of the data about a mean value can be evaluated.The scatter generally follows a guassian distribution about a mean value.whichis assumed to be the true value.Accuracy is the deviation of the output from the calibration input or the true value. If the accuracy of a voltmeter is 2% full scale as described in the preceding section·the maximum deviation i、士2units for all readings.一个随机误差是由于控制,大量的独立影响小,不能他发现或这是一个统计量。
因此,它每个复制的观察。
如果大量的读数是同样数量的不同而不同。
散射的数据值可以评估。
散高斯分布通常遵循关于意味着value.which被认为是真正的价值。
准确性是偏差的输出的输入或真正的校准价值。
如果把电压表的准确性2%全面描述在前面的部分·最大偏差我,士2units所有阅读资料。
测控技术和仪器专业英语翻译殷虹河北工业大学适用
测控专业英语翻译Unit 1 Measurement, Control and InstrumentationInstrumentation is defined as the art and science of measurement and control. Instrumentation engineers are responsible for controlling a whole system like a power plant.译为：仪器可定义为测量和控制的艺术和科学。
仪器工程师负责控制整个系统，比如一个电厂。
An instrument is a device that measures and/or regulates process variables such as flow, temperature, level, or pressure. Instruments include many varied contrivances that can be as simple as valves and transmitters, and as complex as analyzers.译为：仪器是一种用来测量和/或调节过程变量（如流量、温度、液位或压力）的装置。
仪器包括许多不同的设备，可以像阀和变送器那样简单，也可以像分析仪那样复杂。
Instruments often comprise control systems of varied processes such as refineries, factories, and vehicles. The control of processes is one of the main branches of applied instrumentation. Instrumentation can also refer to handheld devices that measure some desired variable. Diverse handheld instrumentation is common in laboratories, but can be found in the household as well. For example, a smoke detector is a common instrument found in most western homes.译为：仪器通常由如精炼厂、工厂和车辆这些不同流程的控制系统组成。
测控技术与仪器专业英语翻译
测控技术与仪器专业英语翻译篇一：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。
测控技术与仪器类外文文献翻译、中英文翻译、外文翻译
附录外文文献翻译本文将简要介绍接触角的应用和测量技术。
主要讨论并比较了这两种测量技术。
什么是接触角？接触角θ是用来定量表征液体对固体的润湿性。
如下面的几何图形所示，接触角是由固体、液体、气体三相边界组成的，有液体一侧到固体部分的角度。
从图中可以看出：接触角θ的值小，则表明液体铺展或者润湿性好。
而接触角θ的值较大，则表明润湿性较差。
如果接触角θ小于90度，也就是说，液体浸润固体，如果接触角的值大于90度，就是说不浸润，而0度接触角表明完全润湿。
用一个单独的静态接触角来表征界面间的相互影响还不是太充分。
对于任意给定的液固界面，总可以一系列存在的接触角。
人们发现，静态接触角的值取决于液固界面的相互影响。
人们把液滴铺展的接触角称为“前进接触角”，而把缩小的接触角称为“后退接触角”。
前进接触角接近于最大值，后退接触角接近于最小值，而这一系列角的值就在这最大值和最小值之间。
在实际运动中，三相(液体、固体、气体)边界产生的角称为动态接触角，也可以指“前进的”和“后退的”的角。
“前进的”和“在前进的”或“后退的”和“在后退的”区别在于在静态运动的开始实际上是动态的。
动态接触角是在各种比率的速度下测定的，在较低的速度下测定的动态接触角应该是静态接触角相等。
滞后现象最大的（前进的/在前进的）和最小的（后退的/在后退的）接触角之间的差值就是接触角的滞后现象。
已经有大量的研究分析了接触角滞后现象的意义。
它通常用来表征表面的多向性、粗糙性和活性。
简而言之，对于不均匀的表面，在表面上出现阻碍接触线移动的区域。
对于化学多向性这种情况，这些区域指的是比周围表面有不同接触角的区域。
下面以水润湿为例，当液体前进而接触角的增加，憎水区域将锁定接触线。
当水从亲水区域退湿时，将阻碍接触线的移动，而减小接触角。
从这些分析中可以看出，用水测试时，前进接触角对憎水区敏感，而后退接触角表征了表面亲水区的特征。
表面粗糙性产生接触角的滞后现象，在这种情况下，显微镜的实际倾斜度的变化在固体表面产生了障碍。
测控技术与仪器专业英语阅读翻译
测控技术与仪器专业英语阅读翻译篇一:测控技术与仪器专业英语课后阅读翻译(1,5__)第1章课后Underwater Acoustic SignalIn the operation of a sonar system the operator is repeatedly faced with the problem of detecting a signal which is obscured by noise. This signal may be an echo resulting from a transmitted signal over which the operator has some control, or it may have its origin in some e_ternal source. These two modes of operation arise in radar surveillance and in disciplines for techniques and for illustrations of the basic principles. Since there are many ways in which one can think about signal detection , it is desirable to define a term to denote special cases . The word detection will be used when the question to be answered is, ?Are one or more signals present?? when the system is designed to provide an answered to this question , either deterministic or probabilistic, one speaks of hypothesis testing. The case of a single signal occurs so often that many system are designed to provide only two answers, ?Yes , a signal is present,? or ?No, there is no signal.? One can make the problem more complicated by endeavoring to classify the signal into categories. Decisions of this latter kind will be referred to as targetclassification.Normally a piece of detection equipment is designed to operate in a fi_ed mode and the parameters such as integrating time of rectifier circuits or persistence of the oscilloscope tube for visual detection cannot be changed readily. There will always be some uncertain signals, which the observer will be hesitant to reject or accept. In these cases the operator might have the feeling that if the integrating time of thedetector or the persistence of the oscilloscope tube were longer, he could reach a decision about the e_istence of the signal. Wald(_50) has formulated this intuitive feeling into a theory of detection. When one is able to vary deliberately the interval over which one stores data in thereception system in order to achieve a certain level of certainty, one speaks of sequential detection. Frequently it is desirable to determine not only the presence or absence of the signal but also one or more parameters associated with the signal . The parameters of interest can vary widely from a simple quantity such as time of arrival or target bearing to the recovery of the completewaveform . When a system is designed to recover one or more parameters associated with thesignal , one speaks of signal e_traction.The word signal was not defined and it was assumed that the reader had an intuitive felling for the word. Some elaboration may be in order since the definition of signal subjective and depends on theapplication . One may say that ?signal? is what one wants to observe and noise is anything that obscures the observation. Thus, a tuna fisherman who is searching the ocean with the aid of sonar equipment will be overjoyed with sounds that are impairing the performance of a nearby sonar system engaged in tracking a submarine. Quite literally, one man?s signal is another man?s noise.Signals come in all shapes and forms. In active sonar system one may use simple sinusoidal signals of fi_ed duration and modulations thereof. There are impulsive signals such as those made withe_plosions or thumpers. At the other e_treme one may make use of pseudorandom signals. In passive systems, the signals whose detection is sought may be noise in the conventional meaning of the word; noise produced by propellers or underwater swimmers, for e_ample. It should be evidentthat one of our problem will be the formulation of mathematical techniques that can be used to describe the signal. Although the source in an active sonar search system may be designed to transmit a signal known shape, there is no guarantee that the return signal whose detection is sought will be similar. In fact , there are many factors to change the signal. The amplitude loss associated with inverse sphericalspreading is most unfortunate for the detection system nut it does not entail any distortion of the wave shape . (Incidentally, where the wave can be appro_imated locally as a plane wave.) The acoustic medium has an attenuation factor , which depends on the frequency . This produces a slight distortion of the wave shape and a corresponding change in the energy spectrum of the pulse. The major changes in the waveform result from acoustic boundaries and inhomogeneities in the medium.When echoes are produced by e_tended targets such as submarines, there are two distinct ways in which echo structure is affected. First, there is the interference between reflections from the different leads to a target strength that fluctuates rapidly with changes in the aspect. Secondly, there is theelongation of the composite echo due to the distribution of reflecting features along the submarines. This means that the duration of the composite echo is dependent in a simple manner on the aspect angle. If T is the duration of the echo from a point scatterer, and L is the length of the submarine, the duration of the returned echo will be T=(2L/c)cosA ,where A is the acute angle between the major a_is of the submarine and the line joining the source and the submarine. C is the velocity of sound in the water. Of course, LcosA must be replaced by the beam width of the submarine when A is near.A final source of pulse distortion is the Doppler shifts produced by the relative motions between the source, and the target (or detector inpassive listening) may each have a different velocity relative to the bottom, the variety of effects may be quite large.水下声波信号在声纳操作过程中,操作员经常需要对受噪声干扰的信号进行检波.干扰信号可能来自操作员发出信号的反射波或者外部声源的信号.这两种类型的干扰对主动声纳和被动声纳都会造成很大影响.类似的情况在雷达监测.工程类和图像类专业的基本原理都会涉及到.当你想到信号检测时有多种方法,那么定义一个术语来表示特殊情况便是可行的.当问题的答案是〝当前有一个还是一个多个信号?〞时,检波一词将被使用.一个系统被设计来为这种问题提供答案--无论是必然性还是偶然性,这就需要谈及假设检验;当一个信号反复出现的情况下,许多系统只被设计提供两个答案:〝是的,当前有一个信号〞或〝不,当前没有信号〞.力图将信号分类会使问题复杂化,因为后者的结论将涉及到目标分类.一般来说,一种检波仪器只被设计在固定的类型和参数下工作,不容易被改变,例如时间积分检波电路和光学检测的辉光示波管.当出现不明信号时,观察者在拒绝或接收信号方面有所迟疑.在这种情况下,操作员会有种感觉如果检波电路或者示波管能够延长时间那么他就能下结论该信号是否存在.沃尔德（_50）在他的检波理论系统阐述了这种直觉.如果（一个检测检测方法）能够主动去改变时间间隔并在接收系统里储存数据以便达到确定的某一水平,这就是顺序检测.一般不仅能够确定信号存在与否,而且还能确定一个或多个与信号关联的参数.在还原完整波形时我们所感兴趣的参数在各简单分量间有很大差别,例如信号的到达时间和相位. 当一个系统被设计来提取一个或多个信号参数时,这就是信号抽取.信号一词并没有明确的定义,只是在读者对它有直观了解时的一种假设.有些较为详细的解释为了对信号一词进定义可能导致是比较主观的或者狭隘与所应用的条件.也许你会说信号就是你想观察到的而噪声就是对观察者产生干扰的信号.但是,一个渔民在用声纳设备搜索海洋时,附近用来追踪潜艇的声纳干扰导致的信号削减常常会使他欣喜若狂.毫不夸张地说,一个人的信号将会是另一个人的噪声.信号的形式和构成是多种多样的.在主动声纳系统中,可以利用相关的固定宽度和调制正弦信号.类似的有脉冲信号,例如爆炸或者撞击.在一些极端的情况可以利用伪随机信号.在被动声纳系统中,例如螺旋桨或潜泳者发出的噪声.很明显,如何利用数学公式的方法来描述一个信号成为了我们所面临的问题.即是在主动声纳系统中的超声波发射器传播已知波形的信号,但无法保证检测后查找出来的反射信号也是类似的波形.振幅和反向球面传播信号失去关联是检波系统最不利的情况,因为它无法承担任何波形畸变.（偶然地,这种事件的乐观情况并不适用于2维波,除非它传播到足够远的地方,可以近似认为是平面波.）声波的传导介质会对其造成衰减,（衰减的程度）取决于声波的频率.这就造成了少量的波形失真和对脉冲波形能谱造成相当的改变.主要的改变还是由于波形的边缘效应和传播介质的不均匀所引起的.当反射波是由外部物体例如潜艇所发出的,这时反射波的结构主要受两种不同方式的影响,第一,由两种反射信号之间的干扰导致外界声源的强度与跟随相位的改变迅速波动,第二,合成反射波的延伸是沿着（来自）潜艇反射的散布特征,这就意味着持续时间取决于相位角的简单特征.如果T是反射波由一个点扩散的持续时间,L是潜艇的长度,那么反射波的回射时间就是 , 是潜艇主轴和声纳拖曳线之间的夹角（锐角）,C则是声音在水中的传播速率.当然,当接近的时候必须用潜艇的宽度代入.最后一个造成脉冲波形失真的原因声源,船体,介质,目标之间相对运动所造成的多普勒效应.由于声源,介质,目标（或者被动接收器的探测端）相对于船体都有不通的速度向量,所以各种因素的影响之间的区别也很大.第五章课后A random erroris due to acontrolled,large number of independent small effects that cannothe identified orit is a statistical quantity. As such,iteach replication of the observations. If a large number of readings iswill vary for the same quantity.the scatter of the data about a mean value can be evaluated.The scatter generally follows a guassian distribution about a meanvalue.whichis assumed to be the true value.Accuracy is the deviation of the output from the calibration input or the truevalue. If the accuracy of a voltmeter is 2% full scale as described in the preceding section·the ma_imum deviation i.士2units for all readings.一个随机误差是由于控制,大量的独立影响小,不能他发现或这是一个统计量.因此,它每个复制的观察.如果大量的读数是同样数量的不同而不同.散射的数据值可以评估.散高斯分布通常遵循关于意味着value.which被认为是真正的价值.准确性是偏差的输出的输入或真正的校准价值.如果把电压表的准确性2%全面描述在前面的部分·最大偏差我,士2units所有阅读资料.第五章.Noncontact Temperature MeasurementAny object at any temperature above absolute zero radiates energy. This radiationvaries both in intensity and in spectral distribution with temperature.Hence.temperature may be deduced by measuring either the intensity or the spectrum of theradiation.The total energy density radiating from an ideal?blackbody?(more on that later) isgiven by the Stefan-boltzmann law·E=6T ·where E is energy density in W/cmz.6 Isthe Stefan-boltzmann constant(5. 6697 _ _ z W/cmz K?)and T is the abs olutetemperature(K).In other words·the total radiated energy is proportional to the fourthpower of the absolute temperature. A_ objects.particularly ideal blackbody objects.also absorb incident radiation.(Uiven time to equilibrate.and presuming they are insulated from the heating or coolingeffects of surrounding air or other materials.they will eventually reach a point wherethey absorb and radiate energy at equal rates. ()ne consequence of this is that if an object(a temperature sensor.for e_ample) is an ideal blackbody.is perfectly insulated.and isflooded on its entire surface with radiation from a radiating source.it will eventuallyreach an equilibrium sources and blackbody calibration sources are available).the temperature of the sensor is a measure of the temperature of the radiating object.任何物体在任何温度高于绝对零度的辐射能量.这种辐射无论是在不同强度和在光谱分布和温度.因此.通过测量温度可以推导出要么强度或频谱的辐射.总能量密度辐射从理想 blackbody〞(稍后详细介绍)鉴于法律的Stefan-boltzmann·E = 6 T ·E在是能量密度在W / cmz. 6Stefan-boltzmann的常数(5. 6697 _ _ z W / cmz K〞)和T是绝对的温度(K).换句话说·总辐射能量是成正比的第四绝对温度的力量.A_对象.特别是理想黑体对象.也会吸收入射辐射.(Uiven 时间一致.和他们隔绝放肆的加热或冷却周围空气的影响或其他材料.他们最终会达到一个临界点他们吸收和辐射能量在相同的利率.()东北的后果是,如果一个对象(一个温度传感器.例如)是一种理想的黑体.是完全绝缘.和是在整个表面淹没与辐射发射源.它最终将达到平衡来源和黑体校正源可用),温度传感器是一个测量辐射的温度对象.An infrared radiation thermometer may be created in a manner similar to that inFigure 1 the radiated energy from the hot(or cold) object is focused on a temperaturesensor.whose temperature then is indicative of the intensity of the radiation falling uponit. The sensor should be small and low mass for reasonable response time. Thermistorsoffer high sensitivity for low temperature measurements while thermocouples providethe operating range necessary for high levels of radiated energy. In some designs.thesensor is insulated from ambient conditions by placingit in a vacuum. The sensor s output is amplified.linearized.and fed to an output indicator or recorder.The optics are apt to be a bit different than shown in diagram. In mostapplications.particularly at lower temperatures.much of the radiation will be farinfrared.which is not passed well by most glasses. It may be preferable to use areflective concave mirror to focus the incoming energy.rather than a lens. There mayalso be a red or infrared filter over the inlet to keep down interference due to strayambient light. For higher temperature use it may be necessary to reduce the totalincoming energy using a gray filter.shutter.or other obstruction. The Stefan-boltzmann law.and the proper operation of thesethermometers.presumes that theradiation is coming from a perfect blackbody radiator. to oversimplify(and it is not ourintention here to which does not reflect any radiation which may fall upon it. Allincident energy is absorbed. A non-blackbody object which reflects e_ternal radiation will also reflect internally generated radiation.lowering the amount of energy radiated atany given temperature.红外辐射温度计可以创建的方式类似,在图1的辐射能量从热(或冷)对象都聚焦在一个温度传感器.其温度然后表明辐射强度落它.应该是小的传感器和低质量为合理的响应时间.热敏电阻提供高灵敏度低温度的测量而热电偶提供必要的工作范围为高水平的辐射能量.在一些designs.the传感器是隔绝外界条件下通过将它放置在真空中.传感器的amplified.linearized输出. 和美联储到输出指标或录音机.光学往往稍有不同,图中所示.在大多数应用程序.特别是在较低的温度下.大部分的辐射将远红外线.这不是大多数眼镜了.这可能比使用凹面镜反射来聚焦入射能量.而不是一个镜头.也许也是一个红色或红外过滤器在进口为了压制干扰由于流浪环境光.温度较高的使用可能需要减少总传入的能源使用灰色filter.shutter. 或其他阻塞Stefan-boltzmann的法律. 和适当的操作这些温度计.是假定辐射是来自一个完美的黑体的散热器.粗略的(和它不是我们的这里的意愿,没有反映出任何辐射可能落在它.所有入射能量被吸收.一个non-blackbody对象反映外部辐射也将反映出内部产生的辐射.降低辐射的能量在任何给定的温度.Any surface has a reflectivity and an emissivity. Reflectivity,r,is simply the ratioof reflected energy to incident energy:a perfect reflector has a reflectivity of one;ablackbody,zero. Emissivity,.,turns out to b simply.=1一re,fZecl:二:Cy reflectivity. Aperfect blackbody has emitted by an object at a given temperature is proportional to itsemissivity:a reflectivity object has emissivity(we e_pect more heat from a rough,blackradiator than from a smooth,polished one). All this has a serious impact on radiation thermometry. An infrared radiationthermometer calibrated against a blackbody radiator will read seriously low when aimedat a reflective object .Most commercial radiation thermometers include a controlallowing the user to dial in the emissivity of the object being measured,plus a table oftypical emissivity values.Mist organic and nonmetallic materials have emissivity values.Most organic and nonmetallic materialshave emissivities between 0. 85 and 0. 95,whilemetals range roughly between 0. 1 and 0. 5(interestingly,both white and black paintshave similar emissivitie.一between 0. 9-at temperatures up to 1_0C).任何表面具有反射率和发射率.反射率r,是简单的比率反射入射能量的能量:一个完美的反射器有一个反射率的;一个黑体,零.辐射率(.其实,b简单.= 1一re,fZecl:二:Cy反射率.一个完美的黑体物体所发出了在给定温度是成正比的辐射率:反射率对象有辐射率(我们希望更多的热量从粗糙的.黑色的散热器比从光滑.磨光的一个). 所有这一切都有严重影响辐射测温.红外辐射对一个黑体温度计校准散热器将认真读书目的时低在反思对象.大多数商业辐射温度计包括控制允许用户来定下的热辐射特性被测对象,再加上一个表典型的辐射值.雾有机和非金属材料有辐射值.大多数有机和非金属材料有emissivities介于0.85年和年0.95年的时候,金属范围大致在0.1和0.5(有趣的是,两个白色和黑色颜料也有类似的emissivitie,一between 0. 9-at温度可达1_0摄氏度).Variations in emissivitiy can cause serious errors,especially with metal surfaces.Highly polished surfaces have lower emissivity still farther. As an o_idation or coatingof the surfaces raises emissivity still farther. As an e_ample,the emissivity of stainlesssteel at 8_0C is when polished,0. 5 when rough machined,0. 7 when rough machinedand lightly o_idized and 0. 8 to 0. 9 when heavily o_idized. If at all possible, the surfaceto be measured should be painted.o_idized.or otherwise made black and noeflective.Liquid metals.a frequent application for infrared thermometry.are not as variable ittheir emissivity.but may be affected by layers of slag on their surface. It is a good ideato calibrated the infrared reading by making a contact temperature measurement or.it the case of liquid metal.by plunging in a thermocouple as described in the previoussection.Also affecting the readings are atmospheric attenuation. Water vapor stronglyattenuates certain infrared wavelengths while dust smoke.and particulate matter wilattenuate the radiation between the source and the sensor. Such problems are apt to bemost troublesome in industrial applications.emissivitiy变化可以导致严重的错误,尤其是在金属表面.高度抛光表面发射率低到更远.作为氧化或涂层表面发射率的提高到更远.作为一个例子,辐射率的不锈钢钢铁8_0 C是当抛光,0.5当粗糙的加工,0.7当粗糙的加工和轻氧化,0.8为0.9当严重氧化.如果可能的话,应该painted.o_idized surfaceto被测量. 或用其他的黑色和以及非反射.液态金属.一个频繁的应用程序为红外测温.不像变量他们的发射率.但可能会受层渣在其表面.这是一个好主意对校准红外阅读通过使接触or.it温度测量此案的液态金属.在一个热电偶大跌之前描述的那样部分.阅读资料也影响大气衰减.水蒸气强烈衰减某些波长红外线虽然灰尘烟.和颗粒物会衰减之间的辐射来源和传感器.这类问题是容易的摘要在工业应用中最麻烦的.The dependence of the measurement upon emissivity can be reduce by the use otwo-color pyrometry. As was mentioned at the start of this section.both the intensityand the spectral distribution of the radiation vary with temperature. The radianintensity at any wavelength.几.is given by:’C }以J-一一一,二二一一二二干下尸一一一丁e_pl l,}/入1一1Where J is the radiant energy·.is the emissivity·} is the wavelength·and T is theabsolute temperature(K).On th e assumption that emissivity is not a function owavelength(this assumption isnot entirely true)the ratio of intensities at twcwavelengths becomes: 测量的依赖性在辐射率可以减少使用o双色印铁测温.就像前面说过的在这一部分的开始.磁性的强度和光谱分布的辐射随温度.弧度在任何wavelength.几强度. 给出: C }以J-一一一,二二一一二二干下尸一一一丁e_pl l,} /入1一1这里J是辐射能·.辐射率·}的是波长·和T是吗绝对温度(K).假设辐射率不是一个函数o 波长(这种假设并不完全正确)的比例在twc公司的强度波长变得:测量的依赖性在辐射率可以减少使用o双色印铁测温.就像前面说过的在这一部分的开始.磁性的强度和光谱分布的辐射随温度.弧度在任何wavelength.几强度. 给出: C }以J-一一一,二二一一二二干下尸一一一丁e_pl l,} /入1一1这里J是辐射能·.辐射率·}的是波长·和T是吗绝对温度(K).假设辐射率不是一个函数o 波长(这种假设并不完全正确)的比例在twc公司的强度波长变得:几.几/巨e_pCC=/J},T 一y/巨e_pCC=/J}=T)一y一一大一大Which may be simplified to=(consl)只e_p大一大wherecn77s/〔丫)7了sC(几:/几)’C}(lid.一1/J},)第6章课后习题3.Uncertainty is generally stated as a number·indicating the tolerance from the true value of the measurand. T he tolerance is only estimated. It represents theconfidence level of the investigator in the results.since the true value of themeasurement is unknown. he purpose of the sensor is to obtain dimensional information from theworkpiece. .不确定性是一般表述数量表示宽容的·过热蒸气的真实价值.他宽容只是估计T.它代表了信心水平的调查员在结果中.自从的真正价值测量是未知的.他的目的是获取维度信息的传感器从theworkpiece.4. It is like a transducer in many instances because it converts oneenergy form to another. This other energy form is always an electrical signal.since we are considering sensors which provide an篇二:测控技术与仪器专业英语课后阅读翻译第五章课后A random erroris due to acontrolled,large number of independent small effects that cannothe identified orit is a statistical quantity. As such,iteach replication of the observations. If a large number of readings iswill vary for the same quantity.the scatter of the data about a mean value can be evaluated.The scatter generally follows a guassian distribution about a mean value.whichis assumed to be the true value.Accuracy is the deviation of the output from the calibration input or the truevalue. If the accuracy of a voltmeter is 2% full scale as described in the preceding section·the ma_imum deviation i.士2units for all readings.一个随机误差是由于控制,大量的独立影响小,不能他发现或这是一个统计量.因此,它每个复制的观察.如果大量的读数是同样数量的不同而不同.散射的数据值可以评估.散高斯分布通常遵循关于意味着value.which被认为是真正的价值.准确性是偏差的输出的输入或真正的校准价值.如果把电压表的准确性2%全面描述在前面的部分·最大偏差我,士2units所有阅读资料.第五章.Noncontact Temperature MeasurementAny object at any temperature above absolute zero radiates energy. This radiationvaries both in intensity and in spectral distribution with temperature.Hence.temperature may be deduced by measuring either the intensity or the spectrum of theradiation.The total energy density radiating from an ideal?blackbody?(more on that later) isgiven by the Stefan-boltzmann law·E=6T ·where E is energy density in W/cmz.6 Isthe Stefan-boltzmann constant(5. 6697 _ _ z W/cmz K?)and T is the absolutetemperature(K).In other words·the total radiated energy is proportional to the fourthpower of the absolute temperature. A_ objects.particularly ideal blackbody objects.also absorb incident radiation.(Uiven time to equilibrate.and presuming they are insulated from the heating or coolingeffects of surrounding air or other materials.they will eventually reach a point wherethey absorb and radiate energy at equal rates. ()ne consequence of thisis that if an object(a temperature sensor.for e_ample) is an ideal blackbody.is perfectly insulated.and isflooded on its entire surface with radiation from a radiating source.it will eventuallyreach an equilibrium sources and blackbody calibration sources are available).the temperature of the sensor is a measure of the temperature of the radiating object.任何物体在任何温度高于绝对零度的辐射能量.这种辐射无论是在不同强度和在光谱分布和温度.因此.通过测量温度可以推导出要么强度或频谱的辐射.总能量密度辐射从理想 blackbody〞(稍后详细介绍)鉴于法律的Stefan-boltzmann·E = 6 T ·E在是能量密度在W / cmz. 6Stefan-boltzmann的常数(5. 6697 _ _ z W / cmz K〞)和T是绝对的温度(K).换句话说·总辐射能量是成正比的第四绝对温度的力量.A_对象.特别是理想黑体对象.也会吸收入射辐射.(Uiven 时间一致.和他们隔绝放肆的加热或冷却周围空气的影响或其他材料.他们最终会达到一个临界点他们吸收和辐射能量在相同的利率.()东北的后果是,如果一个对象(一个温度传感器.例如)是一种理想的黑体.是完全绝缘.和是在整个表面淹没与辐射发射源.它最终将达到平衡来源和黑体校正源可用),温度传感器是一个测量辐射的温度对象.An infrared radiation thermometer may be created in a manner similar to that inFigure 1 the radiated energy from the hot(or cold) object is focused on a temperaturesensor.whose temperature then is indicative of the intensity of the radiation falling uponit. The sensor should be small and low mass for reasonable response time. Thermistorsoffer high sensitivity for low temperature measurements while thermocouples providethe operating range necessary for high levels of radiated energy. In some designs.thesensor is insulated from ambient conditions by placing it in a vacuum. The sensor s output is amplified.linearized.and fed toan output indicator or recorder.The optics are apt to be a bit different than shown in diagram. In mostapplications.particularly at lower temperatures.much of the radiation will be farinfrared.which is not passed well by most glasses. It may be preferable to use areflective concave mirror to focus the incoming energy.rather than a lens. There mayalso be a red or infrared filter over the inlet to keep down interference due to strayambient light. For higher temperature use it may be necessary to reduce the totalincoming energy using a gray filter.shutter.orother obstruction. The Stefan-boltzmann law.and the proper operation of thesethermometers.presumes that theradiation is coming from a perfect blackbody radiator. to oversimplify(and it is not ourintention here to which does not reflect any radiation which may fall upon it. Allincident energy is absorbed. A non-blackbody object which reflects e_ternal radiation will also reflect internally generated radiation.lowering the amount of energy radiated atany given temperature.红外辐射温度计可以创建的方式类似,在图1的辐射能量从热(或冷)对象都聚焦在一个温度传感器.其温度然后表明辐射强度落它.应该是小的传感器和低质量为合理的响应时间.热敏电阻提供高灵敏度低温度的测量而热电偶提供必要的工作范围为高水平的辐射能量.在一些designs.the传感器是隔绝外界条件下通过将它放置在真空中.传感器的amplified.linearized输出. 和美联储到输出指标或录音机.光学往往稍有不同,图中所示.在大多数应用程序.特别是在较低的温度下.大部分的辐射将远红外线.这不是大多数眼镜了.这可能比使用凹面镜反射来聚焦入射能量.而不是一个镜头.也许也是一个红色或红外过滤器在进口为了压制干扰由于流浪环境光.温度较高的使用可能需要减少总传入的能源使用灰色filter.shutter. 或其他阻塞Stefan-boltzmann的法律. 和适当的操作这些温度计.是假定辐射是来自一个完美的黑体的散热器.粗略的(和它不是我们的这里的意愿,没有反映出任何辐射可能落在它.所有入射能量被吸收.一个non-blackbody对象反映外部辐射也将反映出内部产生的辐射.降低辐射的能量在任何给定的温度.Any surface has a reflectivity and an emissivity. Reflectivity,r,is simply the ratioof reflected energy to incident energy:a perfect reflector has a reflectivity of one;ablackbody,zero. Emissivity,.,turns out to b simply.=1一re,fZecl:二:Cy reflectivity. Aperfect blackbody has emitted by an object at a given temperature is proportional to itsemissivity:a reflectivity object has emissivity(we e_pect more heat from a rough,blackradiator than from a smooth,polished one). All this has a serious impact on radiation thermometry. An infrared radiationthermometer calibrated against a blackbody radiator will read seriously low when aimedat a reflective object .Most commercial radiation thermometers include a controlallowing the user to dial in the emissivity of the object being measured,plus a table oftypical emissivity values.Mist organic and nonmetallic materials have emissivity values.Most organic and nonmetallic materialshave emissivities between 0. 85 and 0. 95,whilemetals range roughly between 0. 1 and 0. 5(interestingly,both white and black paintshave similar emissivitie.一between 0. 9-at temperatures up to 1_0C).任何表面具有反射率和发射率.反射率r,是简单的比率反射入射能量的能量:一个完美的反射器有一个反射率的;一个黑体,零.辐射率(.其实,b简单.= 1一re,fZecl:二:Cy反射率.一个完美的黑体物体所发出了在给定温度是成正比的辐射率:反射率对象有辐射率(我们希望更多的热量从粗糙的.黑色的散热器比从光滑.磨光的一个). 所有这一切都有严重影响辐射测温.红外辐射对一个黑体温度计校准散热器将认真读书目的时低在反思对象.大多数商业辐射温度计包括控制允许用户来定下的热辐射特性被测对象,再加上一个表典型的辐射值.雾有机和非金属材料有辐射值.大多数有机和非金属材料有emissivities介于0.85年和年0.95年的时候,金属范围大致在0.1和0.5(有趣的是,两个白色和黑色颜料也有类似的emissivitie,一between 0. 9-at温度可达1_0摄氏度).Variations in emissivitiy can cause serious errors,especially withmetal surfaces.Highly polished surfaces have lower emissivity still farther. As an o_idation or coatingof the surfaces raises emissivity still farther. As an e_ample,the emissivity of stainlesssteel at 8_0C is when polished,0. 5 when rough machined,0. 7 when rough machinedand lightly o_idized and 0. 8 to 0. 9 when heavily o_idized. If at all possible, the surfaceto be measured should be painted.o_idized.or otherwise made black and noeflective.Liquid metals.a frequent application for infrared thermometry.are not as variable ittheir emissivity.but may be affected by layers of slag on their surface. It is a good ideato calibrated the infrared reading by making a contact temperature measurement or.it the case of liquid metal.by plunging in a thermocouple as described in the previoussection.Also affecting the readings are atmospheric attenuation. Water vapor stronglyattenuates certain infrared wavelengths while dust smoke.and particulate matter wilattenuate the radiation between the source and the sensor. Such problems are apt to bemost troublesome in industrial applications.emissivitiy变化可以导致严重的错误,尤其是在金属表面.高度抛光表面发射率低到更远.作为氧化或涂层表面发射率的提高到更远.作为一个例子,辐射率的不锈钢钢铁8_0 C是当抛光,0.5当粗糙的加工,0.7当粗糙的加工和轻氧化,0.8为0.9当严重氧化.如果可能的话,应该painted.o_idized surfaceto被测量. 或用其他的黑色和以及非反射.液态金属.一个频繁的应用程序为红外测温.不像变量他们的发射率.但可能会受层渣在其表面.这是一个好主意对校准红外阅读通过使接触or.it温度测量此案的液态金属.在一个热电偶大跌之前描述的那样部分.阅读资料也影响大气衰减.水蒸气强烈衰减某些波长红外线虽然灰尘烟.和颗粒物会衰减之间的辐射来源和传感器.这类问题是容易的摘要在工业应用中最麻烦的.The dependence of the measurement upon emissivity can be reduce by the。
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译为：一些数字事件，例如使用容积式流量计测定电机或脉冲的流畅性，也必须转化为TTL电平电压才能实现。因此，对模拟和数字信息进行转换的输入/输出 (I/O) 系统的起源和持续发展过程如图 2.1所示。
Digital I/O functionality 数字I/O功能
In contrast to analog transducers（传感器，变频器；变换器）that sense continuous variables such as pressure and temperature, many transducers provide an output that is one of two states: high or low, open or closed. A pressure might be too high or a temperature too low, triggering closure of a switch. Outputs, too, are not strictly analog-solenoid. Valves typically are opened or closed.
译为：早在计算机二进制语言中，对基于微处理器的数据采集系统来说处理这种数字式或分立式的输入输出比处理模拟信号容易。
Similar to analog-to-digital converters used for analog I/O, digital I/O is designed to deal directly with transistor（晶体管）-to-transistor logic (TTL) level voltage changes. TTL typically sets the low voltage level(低电平)between 0 and 0.8V and the high voltage level (高电平) between 2.0 and 5.0V. Voltage levels between 0.8 and 2.0V are not allowed.
译为：与用于模拟输入输出的模拟-数字转换器相类似，数字输入输出用于直接处理TTL电平的变化。通常，TTL电平的低电压为0～0.8V，高电平为2.0～5.0V。0.8～2.0V为无效电压。
A voltage change, then, from the high range to the low range (or vice versa) represents a digital change of state from high to low, on to off, etc. And because acquiring an analog signal is more complex than acquiring a digital one, analog I/O channels also are more expensive. Hence, if digital I/O is adequate, do not bother with analog.
译为：许多水泵和加热器被简单的开启或关闭。脉冲信号是数字I/O的另一种形式，比如涡轮流量计旋转一周或与计算单一、可数事件的转速表。数字I/O也可用于嵌入式扩展卡的并行通信，产生时钟和其他计时信号。
Already in the binary language of computers, these types of digital, or discrete, inputs and outputs (I/O) are much easier for microprocessor-based data acquisition systems to deal with than analog signals.、
译为：为了理解模拟型号在电路中传输的方式，首要需要了解使模拟信号传输成为可能的一些关系。
It is the fundamental relationship between voltage, current, and electrical resistance that allow either a continuously varying current or voltage to represent a continuous process variable.
译为：尽管微处理器和数字网络技术已经彻底改变了如今数据采集系统处理数据的方法，但是，许多实验室和制造业任然沿用以前的方法，通过模拟电信号传递信息。
To understand the ways in which an analog signal is transmitted over a circuit, it is first important to understand the relationships that make analog signal transmission possible.
句中but表示否定，意为“了……”，
译为：现在，数字计算机和其他基于微处理器的设备代替了所有模拟记录和显示器，唯独不能代替最简单的数据采集功能。尽管计算机技术对于数据获取工作确实有积极地影响，但它们只能显示1，0二进制代码。
Manufacturing processes and natural phenomena, however, are still by their very nature analog. That is, natural processes tend to vary smoothly over time, not discontinuously changing states from black to white, from on to off. To be meaningfully recorded or manipulated by a computer then, analog measurements such as pressure, temperature, flow rate, and position must be translated into digital representations.
译为：然而，制造过程和自然现象仍然是一种自然模拟过程。那就是说，自然过程是随着时间的推移逐渐变化的，而不是直接从白到黑，从开到关的间断变化。要使用计算机对模拟量，例如压力、温度、流速、和位置，进行有意义的记录或是控制，必须先将它们转换为相应的数字量。
Inherently digital events, too, such as the tripping（平稳地进行）of a motor or a pulse generated by a positive displacement flow meter（流量计）, must be made interpretable as a transistor-to-transistor logic (TTL) level changes in voltage（TTL电平变化”）.Hence, the origination and ongoing development of input/output (I/O) systems for converting analog and digital information about real-world is shown in Figure 2.1.
此句为强调句型。
译为：是电压、电流和电阻之间的基本原理使得可以用连续变化的电流或电压来表示连续过程变量。
While charge flow is electric current, voltage is the work done in moving a unit of charge (1 coulomb) from one point to another. The unit of voltage is often called the potential difference, or the volt (V). The International System of Units (SI) unit for electrical flow is the ampere (A), defined as one coulomb per second (c/s).
Today, digital computers and other microprocessor-based devices have replaced analog recording and display technologies in all but the simplest data acquisition applications. And while computers have had an undeniably positive impact on the practice of data acquisition, they speak only a binary language of ones and zeroes.
译为：而且，电压从高电平变为低电平代表从高到低或从开到关的信号变化。而且，由于采集模拟信号比采集数字信号复杂，所以模拟输入输出通道也比数字的较为昂贵。而且，如果数字输入输出通道足够，则无需再考虑模拟输入输出通道。
Analog signal transmission 模拟信号传输
Although the microprocessor and have fundamentally reinvented（重复设置，（在不知他人以发明的情况下）重复发明，彻底改造，重新使用） the ways in which today’s data acquisition systems handle data, much laboratory and manufacturing information is still communicated the “old” way, via analog electrical signals.