专业外语教学-专业英语-4-digital-electronics课件

1、English in Electric AutomationSunny Shen4 Digital Electronics prime praim n. 上撇号trigger trig v.引起，触发inversion inv:n n.反相，反转quadruple kwdrupl adj.四合一fabricate fbrikeit v.制造integrated circuit 集成电路capsule kpsju:l n.封装compatible kmptbl adj. 兼容的obsolete bsli: t adj.废弃的threshold rehuld n.阀门， 门限zener diode

2、 齐纳二极管adjacent deisnt adj.邻近的，接近的arc welding 电弧焊intimately intimitli adv.密切地recast ri:k:st v.重做bistable circuit 双稳电路cutoff kt:f 截止，关闭Vocabulary patriot peitrit, pt- n. 爱国者envision invin v.预见alphabet lfbet n.字母表validity vliditi n.正确性proposition .prpzin n. 命题binary bainri n.二进制nevertheless .nevles con

3、j.然而reveal rivi:l v.展现，揭示complement kmplimnt n.补码truth table 真值表algebraical adj.代数的trial and error 试错法，试凑法mechanism meknizm n.机械装置，机构elapse ilps v.（时间）流逝enumerate inju:mreit v.列举expire ikspai, eks- v.期满，终止brute bru:t adj.僵化的symmetry simitri n.对称label leibl v. 为标号equilibria n.平衡lever li:v, lev n. 杆，杠

4、杆latch circuit 锁存电路memory memri n.存储器depress dipres v.压下set set v.置位calculator klkjuleit n.计算器flip-flop flipflp n.触发器glitch glit n.干扰synchronize sikrnaiz v.同步leading edge 上升沿lagging(trailing) edge lgi 下降沿inhibit inhibit v.禁止hitherto .hitu: adv.迄今，至今toggle tgl v.（来回）切换Impulse impls n.推动力 lever actuat

5、ed switch杠杆传动开关toggle switch：扳钮开关、拨动开关frequency devider分频器 HTL=high threshold logic：高阈值逻辑、DTL=diode transistor logic：二极管晶体管逻辑、TTL=Transistor-Transistor Logic：晶体管-晶体管逻辑(电路)CMOS= Complementary Metal-Oxide -Semiconductor Transistor：互补金属氧化物半导体、ECL Emitter-coupled logic：射极耦合逻辑vice versa 反之亦然make out of 用

6、.制造出.lower 早期的Gate and Clocked Flip-Flops：门控和钟控触发器 timing problems定时问题（竞争冒险） cross coupled交叉耦合gating 选通,开启 gating pulse 选通脉冲 gating signal 选通信号 coupling capacitors 耦合电容A Historical Example. “Listen my children and you shall hear / Of the midnight ride of Paul Revere”According to Longfellow s poem, P

7、aul Revere was sent riding through the New England countryside by a signal from the bell tower of the Old North Church in Boston. “One if by land and two if by sea. That is, one light was to be displayed if the British forces were advancing toward Concord by the road from Boston, and two lights were

8、 to be displayed if they were crossing the Mystic River to take an indirect route. 这是一个历史上的例子，“听吧，我的孩子们，你们将会听到/黑夜里保罗里维尔的马蹄声”朗费罗的诗歌中描述，保罗里维尔将根据波士顿老北教堂钟楼的信号骑马越过新英格兰乡间，“一盏灯是陆地，两盏灯是水路”，也就是说，如果英国军队通过陆地从波士顿开往康珂，就用一盏灯表示；如果他们越过神秘河走捷径的话就用两盏灯表示。难句参考翻译BackgroundThis is a historical story about the War of Indep

9、endence of AmericaRelative materials:Road to Revolution.txtRoad to Revolution.mp3The message received by the Patriot was coded in digital form. We would say today that the two “bits” of information were conveyed by the code (strictly speaking, two bits could indicate four possible message and would

10、require distinguishable lights, say one red and one white). The first light signaled that the British were advancing. The second light indicated by what route they were coming. Because only two routes of advance were envisioned, this second bit of information could be interpreted as indicating one o

11、f the two routes.爱国者们收到的信号是数字编码的形式，今天我们将说，是用编码表示两位信息（严格地说，两位可以显示四种可能的信息，并且要求两种不同的灯，比如一盏为红一盏为白）。第一盏灯表示英国人已经出发，第二盏灯表示他们所走的路径。因为只有两条可预见的路线，信息的第二位可以解释为指示两条路径中的一条。Information can be communicate in digital form if the massage is capable of being defined by a series of yes /no statements. There can be only

12、 two states of each variable used in conveying the information. Reducing information to a series of yes/no statements might appear to be a severe limitation on this method, but the method is in fact quite powerful. Numbers can be represented in base 2 and the alphabet by a digital code. 如果信息可以被定义为一系

13、列的是否状态，那么信息就可以用数字的形式进行通信。每个变量只有两种状态用于表达信息。将信息简化为一系列的是否状态似乎是一种严格的限制，但事实上它却是一种非常有效的方法。数字能以2为基数表示，而且字母也可以用它编码。Indeed, any situation with a finite number of outcomes can be reduced to a digital code. Specifically, n digital bits can represent 2n states of possible outcomes. Digital communication takes a

14、 well-defined code known to the parties at both ends, as in our historical example. 毫无疑问的是，任何具有有限位数字的结果都可以用数字编码表示。明显地，2n数字位可以表示结果的2n种可能的状态。像我们的历史上的例子一样，两端的参与者使用明确定义的编码进行通信。 That is, it is desirable to broaden the range of values in the regions for 1 and 0 to allow for variations in transistors, powe

15、r supply voltage, noise that might get mixed in with the signal, and the like.也就是希望扩展1和0区间的有效范围，以考虑到晶体管、电源电压、混杂在信号中的噪声、以及类似因素的变化。allow vi 提供可能性，顾及，考虑到某种可能性The door on a typical elevator has a timer on it which closes the door automatically if no one enters the elevator and pushes a button for anothe

16、r floor.典型的电梯门上有一个定时器，其作用是当没有人进入电梯，并且按下到其它楼层的按钮时可自动关闭电梯门。 This accounts of four of the eight states.这考虑到八个状态中的四个。The truth-table method is a brute-force way for describing a binary function. 真值表是一种描述二进制功能的僵化方法。The NOT S function is represented algebraically by a prime added to the variable or expres

17、sion to be NOTed: S means NOT S.对S取反的代数表达法是在变量或要取反的表达式上加撇号：S表示对S取反。 If we were to draw a circuit diagram for such a system, including all the resistors, diodes, transistors, and interconnections, we would face an overwhelming task, and an unnecessary one. The task would be unnecessary because anyone

18、 who read the circuit diagram would in their mind group the components together into standard circuits and think in terms of the “system” functions of the individual gates.如果我们画出这种系统的电路图，包括所有三极管、二极管和相互连接，我们将面临的是一个不可能完成的，而且是不必要的任务，之所以说是不必要，是因为任何读电路的人都会在心中将这些元器件组织在一起成为标准电路，并且从每个门电路的“系统”功能角度来考虑问题。第一句中使

19、用了虚拟语气，表示不会有人真的会这么做。What will happen if we connect the output of the two-stage amplifier to its input? Fig.4.16 (a) shows the circuit redrawn with this connection made and with turned around to emphasize the symmetry of the resulting circuit. We have also added inputs, which we shall discuss present

20、ly. 如果我们将两级放大器的输入和输出相连，将会发生什么呢？图4.16（a）给出了这样一个电路，它为了强调改动后电路的对称性而重新绘制过。我们还增加了输入端，我们不久将对此加以讨论。Mathematically, this connection requires Ui= U0, which defines a straight lines passing through the origin and having a slope of unity. In Fig.4.16 (b) we have drawn this line on the amplifier characteristic,

21、 which also has to be satisfied. This straight line is not a load line, but the same reasoning applies here as we followed in thinking about load lines: to satisfy both characteristics, the solution must lie at their intersection(S). 从数学上看，这种连接要求Ui=Uo，它定义了一条通过原点，具有相同斜率的直线，图4.16（b）中，我们在放大器特性中画出了这条直线，

22、而放大特性也应当被满足。这条直线不是负载线，但是我们在考虑负载线时所遵守的同样的前提也适合于这里：要满足两种特性，解必须位于它们的交点（S）。as we followed in thinking about load lines为状语从句。reasoning：前提follow：遵守，follow the rules; follow ones instincts.遵守规则；顺从直觉This logic family is useful where electrical noise is a problem, to prevent moderate noise signals, which mig

23、ht leak into the circuit, from affecting the circuit as valid digital signals. 当电噪声成为问题时，这个系列的逻辑器件可用于抑制适度的进入电路的噪声信号，以避免其成为有效数字信号而影响电路的性能。We may accomplish a simpler realization by manipulating the expression for D into a more convenient form.通过将表达式D变换为一种更方便的形式可以获得一个更简单的（电路）实现方法。英语中，后置的定语、状语等在翻译时一般应当

24、前置。 D= (T + B)S=(T+B)+S=(T+B)+S In Eq. (4.2) the first form is the same expression for D as in Fig.4.12, except that we NOTed it twice. We do this because we want the final result for D to be primed, that is, to be the NOT of something. This is required if we are to realize the final operation with

25、a NOR or NAND gates. The second form results from using De Morgans theorem to distribute one of the NOTs to the individual terms. The third form is the same as the second, except that we have removed the double complement from S. 方程4.2中第一个表达式（步）除了我们取了两次非以外，与图4.12中D的表达式一样，这么做是因为如果我们要用与“非和”和“与或”门实现最终的

26、运算的话，我们要将最后的D的结果加“撇”，也就是取反。第二个表达式来源于德摩根定理的应用，以将“非”用于单独的各项。第三步除了我们从S中去掉了双取反号外，与第二步一样。This final form proves convenient for realization with NOR gates. Fig.4.13 shows the realization. Note that we made a NOT out of NOR similar to the way we realized a NOT with a NAND earlier. De Morgans theorem thus l

27、eads to a simpler realization.这一最后的表达式能很方便地用或非门实现。注意我们用或非门得到非门的方法与早前用与非门得到非门的方法类似，从而德摩根定理导致了更简单的电路实现。 In this section we show how memory is developed in logic circuits and how memory elements increase greatly the possible applications of logic circuits. 在这一节中，我们将展示在逻辑电路中存储器如何被逐步引入，以及存储单元如何大大地增加了逻辑电路

28、的应用可能性。 Another problem with the basic R-S flip-flop is the forbidden state at the input. This can be eliminated by ANDing the inputs with the output of the flip-flop, thus blocking one of the inputs, as shown in Fig.4.23.基本RS触发器的另一个问题是输入的禁止状态，这可以通将触发器的输出和输入进行与运算，封锁其中一个输入的方法来消除，如图4.23。The symbol for

29、 an edge triggered（边缘触发） flip-flop is shown in Fig.4.22 for both leading and lagging edge triggering. The distinguishing mark for edge triggering is triangle at the clock input. Triggering at the edge of the waveforms limits the time during which the inputs are active and thus server to eliminate gl

30、itches. By using circuits that trigger at either the leading or trailing edges（上升或下降沿）, the designer can pass signals in a circuit at two times in each clock cycle.边缘触发触发器，包括上升沿触发和下降沿触发的符号见图4.22，边缘触发的区别标志是时钟输入端的三角形。在触发的时间里输入打开，在波形的边缘触发限制了时间，因此减少了干扰。通过在上升沿和下降沿使用电路，设计者可以在每一个时钟周期内两次通过信号。The J-K flip-fl

31、op thus gives us, in addition to a latched memory of the input, the capacity to “toggle” (A lever-actuated switch, like the ordinary light on-off switch, is called a toggle switch. Thus to toggle means to switch from one state to another) when both inputs are 1. This toggle feature reveals why we must use edg