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1、自动化,2023年4月4日4时56分,2,学习的重要性,自动化教材主要包括电子技术、控制理论、计算 机控制技术、电力传动、过程控制等内容，涵盖了自动化专业各个发展方向。,近年来，随着自动化技术的 发展，先进的自动化设备和产品不断出现，国外许多 企业 的产品和设备的使用手册及说明书都是用 英文 编写的，此外，优秀的仿真软件、前沿学科的研究论文、自动化专业优秀教材、互联网上大量的专业技术信息等多数也是英文的。,2023年4月4日4时56分,3,科技英语翻译概述,科技英语文体的特点1.词汇特征,客观，表意精确，简明扼要，相对固定，具有国际通用性,如：copper end rings alternat
2、ing current field winding output modern control system,铜端环,交流电 AC,励磁绕组,输出,现代控制系统,2023年4月4日4时56分,4,科技英语翻译概述,科技英语文体的特点 2.语法、句法特征,The signal levels inside power amplifier are so much larger than these weak inputs that even the slightest leakage from the output back to the input may cause problem 功率放大器中
3、的信号幅度比微弱的输入信号大的多，即使输出的极微小的泄露传输到输入端，都会引发一些问题,陈述客观事实，多用一般现在时和被动语态；多使用介词短语，不定式短语同位语从句、定语从句等修饰；常用it形式主语句型,2023年4月4日4时56分,5,科技英语翻译概述,科技英语文体的特点 2.语法、句法特征,For example,it is the convention with loudspeakers that the volume of the sound should be set by the voltage applied to the speaker.例如，扬声器的音量通常是受所加电压控制。
4、,陈述客观事实，多用一般现在时和被动语态；多使用介词短语，不定式短语同位语从句、定语从句等修饰；常用it形式主语句型,2023年4月4日4时56分,6,科技英语翻译的标准与原则,2.语句通顺流畅、简洁自然，语言 通俗易懂、符合译入语规范,1.忠实原文,2023年4月4日4时56分,7,搞好科技英语翻译应具备的条件,1.科学严谨的态度2.良好的英语语言基础3.熟练地驾驭汉语的能力4.广博的专业及相关领域的知识5.必要的英语翻译理论和技巧6.大量实践经验的积累,2023年4月4日4时56分,8,严俊仁.科技英语翻译技巧.北京：国防工业出版社，2000王宏文等.自动化教程.北京：机械工业出版社，20
5、03朱月珍.英语科技学术论文撰写与投稿.武汉：华中科技大学出版社，2001,Lesson 1 Analog Amplifiers,New words and phrases 1.analog n.类似物 adj.模拟的2.amplifier n.电工扩音器，放大器3.illustrate vt.举例说明，阐明 vi.举例4.audio adj.音频的 n.音响，声音信号5.Hi-Fi n.具有高保真度 6.fidelity n.忠实，诚实，逼真度7.minidisk n.小型磁盘,2023年4月4日4时56分,10,8.approximate adj.近似的 vi.近似，接近9.provide
6、d that 假如，在的条件下10.of the order of 大约,左右11.FM abbr.调频12.tuner n.调谐器，调音者，定弦者13.moderatelyadv.适度地，稳健地14.oscilloscopen.物示波镜，示波管15.voltmeter n.伏特计，电压表16.milliwatt n.毫瓦17.milliamperen.电毫安培18.a.c.abbr.(略语)交流电,2023年4月4日4时56分,11,19.gain n.增益 vt.得到 vi.获利，增加20.voltage gain 电压增益21.impedance n.电阻抗，全电阻22.resistor
7、 n.电电阻，电阻器23.valve n.阀，活门 英电子管 瓣膜24.tube n.管，管子，英地铁25.bipolar adj.双极的，有两极的，两相的26.FET abbr.(略语)场效应管（Field-effect transistor)27.J-FET J型场效应管28.N-channel N沟道29.inverting adj.反相的，倒相的30.boost vt.推进，增加，n.上推，增加,2023年4月4日4时56分,12,31.triode n.电子三极管，真空三极管32.op-amp abbr.(略语)运算放大器33.current adj.当前的 n.涌流，趋势34.in
8、 advance 提前，事前，预先35.simultaneously adv.同时地36.convention n.大会，会议，协定37.overall power总功率38.applied adj.应用的，实用的，施加的39.acoustical adj.听觉的，声学的40.consequence n.结果，逻推理41.sensor n.传感器，灵敏元件42.stimulus n.刺激，刺激物，促进因素,2023年4月4日4时56分,13,43.buffer n.缓冲器，缓冲区vt.缓冲44.in action 在活动，起作用，在运行中45.assert vt.断言，声称，维护，表明46.O
9、hm n.欧姆 电欧姆47.Hz n.赫，赫兹(频率单位：周/秒)赫兹48.demanding adj.过分要求的，苛求的,2023年4月4日4时56分,14,At the most basic level,a signal amplifier does exactly what you expect it makes a signal bigger!However,the way in which it is done does vary with the design of the actual amplifier,the type of signal,and the reason why
10、 we want to enlarge the signal.1 We can illustrate this by considering the common example of a“Hi-Fi”audio system.,Lesson 1 Analog Amplifiers,2023年4月4日4时56分,15,In a typical modern Hi-Fi:system,the signals will come from a unit like a CD player,FM tuner,or a Tape/Minidisk unit.The signals they produc
11、e have typical levels of the order of 100 mV or so when the music is moderately loud.This is a reasonably large voltage,easy to detect with something like an oscilloscope or a voltmeter.However,the actual power levels of these signals are quite modest.Typically,these sources can only provide current
12、s of a few milliamps,which by PVI means powers of just a few milliwatts.A typical loudspeaker will require between a few Watts and perhaps over 100 Watts to produce loud sound.Hence we will require some form of Power Amplifier(PA)to“boost”the signal power level from the source and make it big enough
13、 to play the music.,2023年4月4日4时56分,16,Fig.1.1 shows four examples of simple analog amplifier stages using various types of device.In each case the a.c.voltage gain will usually be approximated by AvR1/R2(1-1)provided that the actual device has an inherent gain large enough to be controlled by the re
14、sistor values chosen.Note the negative sign in expression 1-1 which indicates that the examples all invert the signal pattern when amplifying.2 In practice,gains of the order of up to hundred are possible from simple circuits like this,although it is usually a good idea to keep the voltage gain belo
15、w this.Note also that vacuum state devices tend to be called“valves”in the UK and“tubes”in the USA.,2023年4月4日4时56分,17,Many practical amplifiers chain together a series of analog amplifier stages to obtain a high overall voltage gain.For example,a PA system might start with voltages of the order of 0
16、.1 mV from microphones,and boost this to perhaps 10 to 100 V to drive loudspeakers.This requires an overall voltage gain of 106,so a number of voltage gain stages will be required.,2023年4月4日4时56分,18,In many cases we wish to amplify the current signal level as well as the voltage.The example we can c
17、onsider here is the signal required to drive the loudspeakers in a“Hi-Fi”system.These will tend to have a typical input impedance of the order of 8 Ohms.So to drive,say,100 Watts into such a loudspeaker load we have to simultaneously provide a voltage of 28 Vrms and 3.5 Arms.Taking the example of a
18、microphone as an initial source again a typical source impedance will be around 100 Ohms.Hence the microphone will provide just 1 nA when producing 0.1 mV.This means that to take this and drive 100 W into a loudspeaker the amplifier system must amplify the signal current by a factor of over 106 at t
19、he same time as boosting the voltage by a similar amount.3 This means that the overall power gain required is 1012 i.e.120dB!,2023年4月4日4时56分,19,This high overall power gain is one reason it is common to spread the amplifying function into separately boxed pre-and power-amplifiers.The signal levels i
20、nside power amplifiers are so much larger than these weak inputs that even the slightest leakage from the output back to the input may cause problems.By putting the high-power(high current)and low power sections in different boxes we can help protect the input signals from harm.,2023年4月4日4时56分,20,In
21、 practice,many devices which require high currents and powers tend to work on the basis that it is the signal voltage which determines the level of response,and they then draw the current they need in order to work.4 For example,it is the convention with loudspeakers that the volume of the sound sho
22、uld be set by the voltage applied to the speaker.Despite this,most loudspeakers have an efficiency(the effectiveness with which electrical power is converted into acoustical power)which is highly frequency dependent.To a large extent this arises as a natural consequence of the physical properties of
23、 loudspeakers.We wont worry about the details here,but as a result a loudspeakers input impedance usually varies in quite a complicated manner with the frequency.(Sometimes also with the input level.),2023年4月4日4时56分,21,Fig.1.2 shows a typical example.In this case,the loudspeaker has an impedance of
24、around 12 Ohms at 150 Hz and 5 Ohms at 1 kHz.So over twice the current will be required to play the same output level at 1 kHz than is required at 150 Hz.The power amplifier has no way to“know in advance”what kind of loudspeaker you will use,so simply adopts the convention of asserting a voltage lev
25、el to indicate the required signal level at each frequency in the signal and supplying whatever current the loudspeaker then requires.,2023年4月4日4时56分,22,This kind of behavior is quite common in electronic systems.It means that,in information terms,the signal pattern is determined by the way the volt
26、age varies with time,and ideally the current required is then drawn.Although the above is based on a high-power example,a similar situation can arise when a sensor is able to generate a voltage in response to an input stimulus but can only supply a very limited current.In these situations we require
27、 either a current amplifier or a buffer.These devices are quite similar,and in each case we are using some form of gain device and circuit to increase the signal current level.However,a current amplifier always tries to multiply the current by a set amount.Hence it is similar in action to a voltage
28、amplifier which always tries to multiply the signal current by a set amount.The buffer differs from the current amplifier as it sets out to provide whatever current level is demanded from it in order to maintain the signal voltage told to assert.Hence it will have a higher current gain when connecte
29、d to a more demanding load.,2023年4月4日4时56分,23,150Hz,1kHz,返回,2023年4月4日4时56分,24,However,the way in which it is done does vary with the design of the actual amplifier,the type of signal,and the reason why we want to enlarge the signal.1 然而，信号的放大方式随着实际放大器的设计、信号的类型以及放大信号目的的不同而变化。,本句为强调句型，句中的定语从句in which
30、this is done修饰主语the way，does用于强调谓语vary。短语结构the design of the actual amplifier与the type of signal及and the reason why we want to enlarge the signal并列作为介词with的宾语。why 引导的定语从句修饰the reason。,返回,2023年4月4日4时56分,25,Note the negative sign in expression 1-1 which indicates that the examples all invert the signa
31、l pattern when amplifying.注意，表达式1-1中的负号说明，示例中的电路在放大时改变了信号的极性。句中which引导的定语从句和介词短语in expression 1-1修饰动词Note的宾语the negative sign，that引导的宾语从句在定语从句中作宾语，副词all和分词结构when amplifying修饰谓语动词invert。,返回,2023年4月4日4时56分,26,This means that to take this and drive 100 W into a loudspeaker the amplifier system must amp
32、lify the signal current by a factor of over 106 at the same time as boosting the voltage by a similar amount.这就表示要接受这种输入信号并去驱动100瓦的扬声器，放大电路就必须将信号的电流和电压同时放大106倍。句中that引导的从句作谓语动词means的宾语，不定式短语to take在宾语从句中作目的状语，by a factor为从句中的方式状语。,返回,2023年4月4日4时56分,27,In practice,many devices which require high curr
33、ents and powers tend to work on the basis that it is the signal voltage which determines the level of response,and they then draw the current they need in order to work.实际上，许多需要大电流和大功率的设备往往都在特定的条件下工作，即由信号的电压决定响应的幅度，继而由设备吸收其所需要的电流而工作。句中which引导的定语从句修饰主语many devices，介词短语on the basis作状语，that引导的定语从句修饰the basis，which引导的从句定语修饰the signal voltage，they need为省略了关系代词的定语从句，修饰draw的宾语the current。,返回,
