信息科学与电子工程专业英语.pptx

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1、1开场白：好的英语是“读”出来的学习任何语言都要大量阅读。“熟读唐诗三百首，不会作诗也会吟”。大凡读得多的人，语言表达能力都比较强。学英语也要大量阅读。英语好的人，一般说来都读过相当数量的书。只有读得多的人才能真正学好英语。很多人热衷于做题目，以为这是学英语的正确途径。做的试题一套又一套，英语水平却并无实质性提高。好的英语是“读”出来的，不是做练习“做”出来的。“读”出来的英语是地道的，自然的，因为学的是“语感”。“做”出来的英语往往流于生硬，因为是依赖“语法规则”硬做的。第1页/共88页2开场白：好的英语是“读”出来的我主张一口气读下去，即便有个别单词挡道，只要不影响整体内容的理解，就不必停

2、下来查词典，因为那样会打断思路，影响阅读速度，甚至扼杀阅读兴趣。阅读主要目的在于语言吸收上的潜移默化，在于获得语感。阅读需要“量”，没有大量语言“输入”难以学好英语。国内学习者恰恰语言输入量太少，输出量就更少，往往事倍功半。练习要做，但要适量；重要的是阅读，大量的阅读。节引自：黄源深，英语阅读也轻松，文汇报，2004.8.2第2页/共88页Unit OneElectronics:Analog and Digital第3页/共88页Part IIdeal Operational Amplifiers and Practical Limitations第4页/共88页5New Wordsopera

3、tional amplifier operational amplifier 运算放大器运算放大器运算放大器运算放大器op amp op amp 运放的简写运放的简写运放的简写运放的简写 parameters parameters 参数参数参数参数specification specification 指标指标指标指标 methodical methodical 有方法的，有系统的有方法的，有系统的有方法的，有系统的有方法的，有系统的doom doom 注定注定注定注定 objectiveobjective目的目的目的目的prototype prototype 原型，样机原型，样机原型，样机原

4、型，样机 drastically drastically 激烈地，彻底地激烈地，彻底地激烈地，彻底地激烈地，彻底地striking striking 惊人的，醒目的惊人的，醒目的惊人的，醒目的惊人的，醒目的 gain gain 增益增益增益增益closed-loop gain closed-loop gain 闭环增益闭环增益闭环增益闭环增益 output swing output swing 输出电压变化范围输出电压变化范围输出电压变化范围输出电压变化范围supply rails supply rails 电源供给线电源供给线电源供给线电源供给线 data sheet data sheet

5、技术规格表技术规格表技术规格表技术规格表relevance relevance 有关，适当有关，适当有关，适当有关，适当 moral moral 道德，寓意道德，寓意道德，寓意道德，寓意impedance impedance 阻抗阻抗阻抗阻抗 dissipation dissipation 消耗消耗消耗消耗bias current bias current 偏置电流偏置电流偏置电流偏置电流 第5页/共88页6New Wordsresistance resistance 电阻电阻电阻电阻drift drift 漂移漂移漂移漂移 transient transient 瞬态的瞬态的瞬态的瞬态的sl

6、ew rate slew rate 转换率，斜率转换率，斜率转换率，斜率转换率，斜率 linearity linearity 线性线性线性线性trimming trimming 微调微调微调微调 retrospective retrospective 回顾的回顾的回顾的回顾的tricky tricky 机敏的，狡猾的机敏的，狡猾的机敏的，狡猾的机敏的，狡猾的 worst-case value worst-case value 最不利的数值最不利的数值最不利的数值最不利的数值mandatory mandatory 命令的，必须的命令的，必须的命令的，必须的命令的，必须的 desirability

7、 desirability 可取性，值得可取性，值得可取性，值得可取性，值得sledgehammer sledgehammer 大锤大锤大锤大锤 transducer transducer 传感器，变换器传感器，变换器传感器，变换器传感器，变换器offset voltage drift offset voltage drift 补偿电压的漂移补偿电压的漂移补偿电压的漂移补偿电压的漂移 negligible negligible 可忽略的可忽略的可忽略的可忽略的unquoted unquoted 未注明的未注明的未注明的未注明的 proportion proportion 比例比例比例比例plu

8、g plug 插入插入插入插入 第6页/共88页71In order to discuss the ideal parameters of operational amplifiers,we must first define the terms,and then go on to describe what we regard as the ideal values for those terms.At first sight,the specification sheet for an operational amplifier seems to list a large number o

9、f values,some in strange units,some interrelated,and often confusing to those unfamiliar with the subject.对这些指标项讲述我们所认为对这些指标项讲述我们所认为的理想值的理想值经常使那些对运放不熟悉的人感到迷经常使那些对运放不熟悉的人感到迷惑惑第7页/共88页81The approach to such a situation is to be methodical,and take the necessary time to read and understand each definit

10、ion in the order that it is listed.Without a real appreciation of what each means,the designer is doomed to failure.The objective is to be able to design a circuit from the basis of the published data,and know that it will function as predicted when the prototype is constructed.1 按照列出的次序阅读并理解每按照列出的次

11、序阅读并理解每一个定义一个定义能按公布的数据设计电路，并确认构建的样机能按公布的数据设计电路，并确认构建的样机具有预计的功能具有预计的功能 第8页/共88页91It is all too easy with linear circuits,which appear relatively simple when compared with todays complex logic arrangements,to ignore detailed performance parameters which can drastically reduce the expected performance.

12、2 对于线性电路，它们与现在的复杂逻辑电路结构相比看起来对于线性电路，它们与现在的复杂逻辑电路结构相比看起来对于线性电路，它们与现在的复杂逻辑电路结构相比看起来对于线性电路，它们与现在的复杂逻辑电路结构相比看起来较为简单，（因而在设计中）太容易忽视具体的性能参数了，较为简单，（因而在设计中）太容易忽视具体的性能参数了，较为简单，（因而在设计中）太容易忽视具体的性能参数了，较为简单，（因而在设计中）太容易忽视具体的性能参数了，这些（参数）可极大地削弱预期性能。这些（参数）可极大地削弱预期性能。这些（参数）可极大地削弱预期性能。这些（参数）可极大地削弱预期性能。本句主要结构：本句主要结构：It i

13、s easy to ignore It is easy to ignore 第9页/共88页102 An exampleLet us take a very simple but striking example.Consider a requirement for an amplifier having a voltage gain of 10 at 50 kHz driving into a 10 kW load.3 A common low-cost,internally frequency-compensated op amp is chosen;it has the required

14、 bandwidth at a closed-loop gain of 10,and it would seem to meet the bill.4 The device is connected,and it is found to have the correct gain.考虑对一个考虑对一个50kHz50kHz频率时电压增益为频率时电压增益为1010的放大器驱动的放大器驱动10k10kW WW W负载时的要求负载时的要求（注意（注意atat和和intointo的用法）的用法）看来满足价格要求看来满足价格要求（billbill：帐单）：帐单）第10页/共88页112But it wil

15、l only produce a few volts output swing when the data clearly shows that the output should be capable of driving to within two or three volts of the supply rails.5 The designer has forgotten that the maximum output voltage swing is severely limited by frequency,and that the maximum low-frequency out

16、put swing becomes limited at about 10 kHz.它只能产生几伏的电压输出范围，然而数据却它只能产生几伏的电压输出范围，然而数据却清楚地显示输出应能驱动达到电源电压范围以清楚地显示输出应能驱动达到电源电压范围以内内2 2到到3 3伏。伏。第11页/共88页122Of course,the information is in fact on the data sheet,but its relevance has not been appreciated.This sort of problem occurs regularly for the inexperi

17、enced designer.So the moral is clear:always take the necessary time to write down the full operating requirements before attempting a design.Attention to the detail of the performance specification will always be beneficial.It is suggested the following list of performance details be considered:注意句型

18、：注意句型：It is suggested the list be It is suggested the list be considered.considered.第12页/共88页1321.Closed loop gain accuracy,stability with temperature,time and supply voltage2.Power supply requirements,source and load impedances,power dissipation3.Input error voltages and bias currents.Input and out

19、put resistance,drift with time and temperature4.Frequency response,phase shift,output swing,transient response,slew rate,frequency stability,capacitive load driving,overload recovery第13页/共88页1435.Linearity,distortion and noise6.Input,output or supply protection required.Input voltage range,common-mo

20、de rejection7.External offset trimming requirement Not all of these terms will be relevant,but it is useful to remember that it is better to consider them initially rather than to be forced into retrospective modifications.而不要被迫返工而不要被迫返工第14页/共88页154 All parameters are subject to wide variations Neve

21、r forget this fact.How many times has a circuit been designed using typical values,only to find that the circuit does not work because the device used is not typical?6 The above statement thus poses a tricky question:when should typical values and when should worst-case values be used in the design?

22、有多少次是在用典型值设计好电路后发现（该有多少次是在用典型值设计好电路后发现（该电路）只是因为使用的器件不典型而不能工作电路）只是因为使用的器件不典型而不能工作？在设计中何时应该使用典型值，何时应该在设计中何时应该使用典型值，何时应该使用最不利值？使用最不利值？第15页/共88页164This is where the judgment of the experienced designer must be brought to bear.Clearly,if certain performance requirements are mandatory,then worst-case valu

23、es must be used.In many cases,however,the desirability of a certain defined performance will be a compromise between ease of implementation,degree of importance,and economic considerations.7某一规定的性能是否可取要在易实现性，某一规定的性能是否可取要在易实现性，重要性，经济性之间取得折中。重要性，经济性之间取得折中。第16页/共88页175 Do not over-specify or over-desig

24、n In the end,we are all controlled by cost,and it is really pointless taking a sledgehammer to crack a nut,Simplicity is of the essence since the low parts count implementation is invariably cheaper and more reliable.8 杀鸡用牛刀杀鸡用牛刀 用较少元器件实现（的电路）总是更便宜也更可靠。用较少元器件实现（的电路）总是更便宜也更可靠。low parts count implemen

25、tationlow parts count implementation：用零件少的实现方案。：用零件少的实现方案。low countlow count：低的计数，数量少。：低的计数，数量少。partsparts：零件。：零件。第17页/共88页186As an example of this judgment about worst-case design,consider a low-gain DC transducer amplifier required to amplify 10 mV from a voltage source to produce an output of l V

26、 with an accuracy of 1%over a temperature range of 070C.9 Notice that the specification calls for an accuracy of 1%.This implies that the output should be 1 V 10 mV from 0 70C.一个低增益直流传感器放大器，要求将电压源输出的一个低增益直流传感器放大器，要求将电压源输出的10mV10mV信号放大，产生信号放大，产生1V1V的输出，在的输出，在070070 C C范围内达到范围内达到 1%1%的精度的精度 第18页/共88页1

27、96The first step is,of course,to consider our list above,and decide which of the many parameters are relevant.Two of the most important to this(very limited)specification are offset voltage drift and gain stability with temperature.We will assume that all initial errors are negligible(rarely the cas

28、e in practice).对这样（非常有限）的参数，两项最重对这样（非常有限）的参数，两项最重要的指标是电压偏移和对于温度的增益要的指标是电压偏移和对于温度的增益稳定性。稳定性。假设所有的初始误差可以忽假设所有的初始误差可以忽略不计略不计 第19页/共88页206The experienced designer would know that most op amps have a very large open-loop gain,usually very much greater than 10000.A closed-loop gain change of 1%implies tha

29、t the loop gain(as explained later)should change by less than 100%for a closed-loop gain of 100.10闭环增益闭环增益 1%1%的变化意味着环路增益（将在下面的变化意味着环路增益（将在下面说明）的变化在闭环增益为说明）的变化在闭环增益为100100时应该小于时应该小于 100%100%。第20页/共88页216This is clearly so easily fulfilled that the designer knows immediately that he can use typical o

30、pen-loop gain values in his calculations.However,offset voltage drift is another matter.Many op amp specifications include only typical values for offset voltage drift;this may well be in the order of 5 mV/C,with an unquoted maximum for any device of 30 mV/C.11 许多运放技术指标仅仅给出补偿电压偏移的典型值，这许多运放技术指标仅仅给出补偿

31、电压偏移的典型值，这很可能会在很可能会在5 5 m m m mV/V/C C的数量级，而未给出任何器件可以达的数量级，而未给出任何器件可以达到的最大值到的最大值30 30 m m m mV/V/C C。第21页/共88页226If by chance we use a device which has this worst-case drift,then the amplifier error could be 3070=2100mV=2.1 mV over temperature,which is a significant proportion of our total allowable

32、 error from all sources.放大器随温度而产生的误差可为放大器随温度而产生的误差可为2.1 mV2.1 mV占所有误差源所产生的总的允许误差占所有误差源所产生的总的允许误差的相当大一部分的相当大一部分 第22页/共88页237Here is a case,then,where one can be confident that the typical value of open-loop gain can be used,but where the maximum value of drift may well cause significant errors.This s

33、ort of judgment is essential in careful design,and great care is required in interpreting manufacturers data.This consideration must be extended to all the details listed above apart from the fact that worst-case values are often not quoted.这就是我们可以肯定可使用开环增益这就是我们可以肯定可使用开环增益典型值的情况，不过最大漂移很可能典型值的情况，不过最大

34、漂移很可能导致相当大的误差。导致相当大的误差。最不利值通常是不会注最不利值通常是不会注明的明的第23页/共88页247It is often found that values given are not 100%tested.Statistical testing is employed which,for example,guarantees that 90%of all devices fall within the range specified.It could be very inconvenient for the user who relies on the specified

35、 performance and then finds that he has several of the other 10%actually plugged into his circuit.12 对于某些用户可能很不方便，他们依赖于技术指标所给出的性对于某些用户可能很不方便，他们依赖于技术指标所给出的性能，而随后发现却有能，而随后发现却有“另外另外”10%10%的器件被用在了他们的电的器件被用在了他们的电路中。路中。第24页/共88页Part IIData Registers and Counters 第25页/共88页26New Wordsregister register 寄存器寄存

36、器寄存器寄存器shift register shift register 移位寄存器移位寄存器移位寄存器移位寄存器 word of data word of data 数据中的数据中的数据中的数据中的“字字字字”flip-flop flip-flop 双稳态触发器双稳态触发器双稳态触发器双稳态触发器 D flip-flop DD flip-flop D触发器触发器触发器触发器 bus bus 总线总线总线总线synchronous synchronous 同步的同步的同步的同步的 latch latch 锁存（器）锁存（器）锁存（器）锁存（器）in series in series 串接串接串

37、接串接 clock pulse clock pulse 时钟脉冲时钟脉冲时钟脉冲时钟脉冲serial-in serial-out serial-in serial-out 串进串出串进串出串进串出串进串出serial-in parallel-out serial-in parallel-out 串进并出串进并出串进并出串进并出leading edge leading edge（脉冲的）前沿（脉冲的）前沿（脉冲的）前沿（脉冲的）前沿falling edgefalling edge（脉冲的）下降沿（脉冲的）下降沿（脉冲的）下降沿（脉冲的）下降沿preset preset 预置预置预置预置 asyn

38、chronous asynchronous 非同步的，异步的非同步的，异步的非同步的，异步的非同步的，异步的peripheral peripheral 外围的，外围设备外围的，外围设备外围的，外围设备外围的，外围设备parallel logic circuitryparallel logic circuitry并行逻辑电路并行逻辑电路并行逻辑电路并行逻辑电路vice versa vice versa 反之亦然反之亦然反之亦然反之亦然sophistication sophistication 复杂性复杂性复杂性复杂性第26页/共88页27New Wordsweighted coding weig

39、hted coding 加权编码加权编码加权编码加权编码binary binary 二进制的二进制的二进制的二进制的unary unary 一元的一元的一元的一元的counter counter 计数器计数器计数器计数器power of two 2power of two 2的幂的幂的幂的幂modulo modulo 模，取模的模，取模的模，取模的模，取模的configure configure 配置配置配置配置timing diagram timing diagram 时序图时序图时序图时序图ripple ripple 波纹，波动，飘动波纹，波动，飘动波纹，波动，飘动波纹，波动，飘动carr

40、y carry 进位进位进位进位ripple carry adder ripple carry adder 纹波进位加法器纹波进位加法器纹波进位加法器纹波进位加法器chip chip 芯片芯片芯片芯片BCD BCD 二十进制二十进制二十进制二十进制number base number base 数制数制数制数制clear input clear input 清零端清零端清零端清零端gating gating 用门电路作逻辑运算用门电路作逻辑运算用门电路作逻辑运算用门电路作逻辑运算presetable presetable 可预置的可预置的可预置的可预置的up-down counter up-d

41、own counter 可逆计数器可逆计数器可逆计数器可逆计数器programmable programmable 可编程的可编程的可编程的可编程的trailing edge trailing edge 后沿，下降沿后沿，下降沿后沿，下降沿后沿，下降沿第27页/共88页281 Data register The simplest type of register is a data register,which is used for the temporary storage of a“word”of data.In its simplest form,it consists of a se

42、t of N D flip-flops,all sharing a common clock.All of the digits in the N bit data word are connected to the data register by an N-line“data bus”.由共用一个时钟的一组由共用一个时钟的一组N N 个个D D触发器触发器组成组成 第28页/共88页291Figure 1.1 shows a 4 bit data register,implemented with four D flip-flops.The data register is said to

43、 be a synchronous device,because all the flip-flops change state at the same time.第29页/共88页302 Shift registers Another common form of register used in computers and in many other types of logic circuits is a shift register.It is simply a set of flip-flops(usually D latches or RS flip-flops)connected

44、 together so that the output of one becomes the input of the next,and so on in series.1它就是一组触发器（通常是它就是一组触发器（通常是D D锁存器或锁存器或RSRS触发器）联触发器）联在一起，使其中一个触发器的输出成为下一个的输入，在一起，使其中一个触发器的输出成为下一个的输入，依此形成一串。依此形成一串。第30页/共88页312 It is called a shift register because the data is shifted through the register by one bit

45、 position on each clock pulse.2 Figure 1.2 shows a 4 bit shift register,implemented with D flip-flops.它称为移位寄存器，因为数据在每一个时它称为移位寄存器，因为数据在每一个时钟脉冲的作用下通过寄存器移动一位。钟脉冲的作用下通过寄存器移动一位。第31页/共88页323 On the leading edge of the first clock pulse,the signal on the DATA input is latched in the first flip-flop.On the

46、leading edge of the next clock pulse,the contents of the first flip-flop is stored in the second flip-flop,and the signal which is present at the DATA input is stored in the first flip-flop,etc.3 Because the data is entered one bit at a time,this called a serial-in shift register.在下一个时钟脉冲的前沿，第一个触发器的

47、内容被存放在下一个时钟脉冲的前沿，第一个触发器的内容被存放到第二个触发器中，而在数据输入端的信号则存放在第到第二个触发器中，而在数据输入端的信号则存放在第一个触发器中，依此类推。一个触发器中，依此类推。第32页/共88页333Since there is only one output,and data leaves the shift register one bit at a time,then it is also a serial out shift register.(Shift registers are named by their method of input and out

48、put;either serial or parallel.)Parallel input can be provided through the use of the preset and clear inputs to the flip-flop.每次从移位寄存器输出每次从移位寄存器输出1 1比特数据比特数据通过预置和清除触发器输入端可以提供通过预置和清除触发器输入端可以提供并行输入并行输入第33页/共88页343The parallel loading of the flip-flop can be synchronous(i.e.,occurs with the clock pulse

49、)or asynchronous(independent of the clock pulse)depending on the design of the shift register.4 Parallel output can be obtained from the outputs of each flip-flop as shown in Figure 1.3.触发器的并行加载可以是同步的，或者异步的，取决于移位触发器的并行加载可以是同步的，或者异步的，取决于移位寄存器的设计。寄存器的设计。第34页/共88页354Communication between a computer and

50、 a peripheral device is usually done serially,while computation in the computer itself is usually performed with parallel logic circuitry.A shift register can be used to convert information from serial form to parallel form,and vice versa.Many different kinds of shift registers are available,dependi