電氣專業英語文章翻譯
國際化專案合作及國際間科學技術的交流發展迅速,學習專業英語就顯得十分重要。下面是小編帶來的，歡迎閱讀!
1
第二章第一篇
To say that we live in an age of electronics is an understatement. From the omnipresent integrated circuit to the equally omnipresent digital computer, we encounter electronic devices and systems on a daily basis. In every aspect of our increasingly technological society— whether it is science, engineering, medicine, music, maintenance, or even espionage—the role of electronics is large, and it is growing.
談論關於我們生活在一個電子學時代的論調是一種空泛的論調。從無處不在的積體電路到同樣無處不在的數字計算機，我們在日常活動中總會遇到電子裝置和電子系統。在我們日益發展的科技社會的方方面面——無論是在科學、工程、醫藥、音樂、維修方面甚至是在諜報方面——電子學的作用是巨大的，而且還將不斷增強。
In general, all of the tasks with which we shall be concerned can be classified as "signal-processing“tasks. Let us explore the meaning of this term
一般說來，我們將要涉及到的工作被歸結為“訊號——處理”工作，讓我們來探究這個術語的含義吧。
A signal is any physical variable whose magnitude or variation with time contains information. This information might involve speech and music, as in radio broadcasting, a physical quantity such as the temperature of the air in a room, or numerical data, such as the record of stock market transactions. The physical variables that can carry information in an electrical system are voltage and current. When we speak of "signals", therefore, we refer implicitly to voltages or currents. However, most of the concepts we discuss can be applied directly to systems with different information-carrying variables. Thus, the behavior of a mechanical system in which force and velocity are the variables or a hydraulic system in which pressure and flow rate are the variables can often be modeled or represented by an equivalent electrical system. An understanding of the behavior of electrical systems, therefore, provides a basis for understanding a much broader range of phenomena.
訊號就是其與時間有關的量值或變化包含資訊的任何物理變數。這種資訊或許像無線電廣播的演講和音樂，或許是像室內溫度的物理量，或許像股市交易記錄的數字資料。在電氣系統中能夠載有資訊的物理變數是電壓和電流。因此當我們談到“訊號”，我們不言而喻指的是電壓和電流，然而，我們要討論的大多數概念是可以被直接應用於載有不同資訊的變數的系統，因此，一個機械系統在這個系統中力和速度是其變數或者液壓系統在這個系統中壓力和流速是其變數的效能通常可以用一個等效的電氣系統來模擬或表示。因此，我們對於電氣系統性能的理解為理解更寬領域的現象打下了一個基礎。
A signal can carry information in two different forms. In an analog signal the continuous variation of the voltage or current with time carries the information. An example, in Fig.2-l, is the voltage produced by a thermocouple pair when the two junctions are at different temperatures. As the temperature difference between the two junctions varies, the magnitude of the voltage across the thermocouple pair also varies. The voltage thus provides an analog representation of the temperature difference.
一個訊號可以以兩種形式來承載資訊。在一個模擬訊號中電壓或電流隨時間而產生的連續變化載有資訊。在圖2-1中，當一對熱電偶的接頭處於不同的溫度時由熱電偶所產生的電壓就是一個例子。當兩個接頭之間的溫度差改變時，一對熱電偶兩端的電壓也將改變。於是電壓就提供了溫度差的模擬表現形式
The other kind of signal is a digital signal. A digital signal is one that can take on values within two discrete ranges. Such signals are used to represent ON-OFF or YES-NO information. An ordinary household thermostat delivers a digital signal tocontrol the furnace. When the room temperature drops below a preset value, the thermostat switch closes turning on the furnace. Once the room temperature rises high enough, the switch opens turning off the furnace. The current through the switch provides a digital representation of the temperature variation: ON equals "too cold" while OFF equals "not too cold".
另一種的訊號是數字訊號。數字訊號是在兩個離散的範圍內能夠呈現一定數值的訊號。這種訊號常用以表示“開—關”或“是—不是”資訊。一個普通的家用恆溫器傳遞一種數字訊號來控制爐子當房間的溫度下降到預定溫度以下時，恆溫器的開關合上使爐子開始加熱;一旦房間的溫度上升到足夠高，開關就斷開使爐子關閉。流過開關的電流提供了溫度變化的數字表示：ON即為“太冷”而OFF即為“不太冷”
A signal-processing system is an interconnection of components and devices that can accept an input signal or a group of input signals, operate on the signals in some fashion either to extract or improve the quality of the information, and present the information as an output in the proper form at the proper time.
一個訊號處理系統是某些元件或裝置之間的相互連線，這些元件和裝置能夠接收一個輸入訊號或一組輸入訊號，訊號處理系統以某種方式來處理這些訊號即提取這些訊號或提高這些訊號的品質，然後在適當的時間以適當的形式把這個訊號表示為輸出量。
Fig.2-2 illustrates the components in such a system. The central circles represent the two types of signal processing digital and analog, while theblock between the two signal- processing blocks represents the conversion of an analog signal to equivalent digital form A/D=Analog-to-Digital and the reverse conversion of a digital signal to the corresponding analog form D/A=Digital-to-Analog. The remaining blocks involve inputs and outputs— getting signals into and out of the processing system.
圖2-2顯示了這樣一個系統的組成部分。中間的圓圈代表了兩種型別的訊號處理數字和模擬，而處於訊號處理框之間的方框表示模擬訊號向等效數字形式A/D即模擬到數字的轉換，以及從數字訊號向相應的模擬形式D/A即數字到模擬的逆轉換。剩下的方框涉及輸入和輸出——取得訊號以及從處理系統輸出訊號。
Many electrical signals derived from physical systems are obtained from devices called transducers. We have already encountered an example of an analog transducer, the thermocouple pair. It converts temperature difference the physical variable to a voltage the electrical variable. Generally, a transducer is a device that converts a physical or mechanical variable to an equivalent voltage or current signal. Unlike the thermocouple example, however, most transducers require some form of electrical excitation to operate
從物理系統獲得的很多電氣訊號是從被稱為感測器的器件中輸入的。我們已經碰到了一個模擬感測器的例子。即熱電偶。它把溫度的變化物理變數轉換成電壓電氣變數。通常，感測器是一種將物理或機械變數轉換成等效電壓或電流訊號的器件。然而，不同於熱電偶例子，大多數感測器需要一些形式的電激勵以驅動感測器
The output from a system can be in many forms, depending on the use to be made of the information contained in the input signals. One can seek to display the information, either in analog form using a meter, for example, in which the needle position indicates the size of the variable of interest or in digital form using a set of digital display elements that are lit up with a number corresponding to the variable of interest. Other possibilities are to convert the output to sound energy with a loudspeaker, or to use the output asan input signal to another system, or to use the output as a control signal to initiate some action.
個系統的輸出可以有多種形式，這取決於包含在輸入訊號中的資訊所起的作用。我們可以選擇何種方式顯示這些資訊，無論是以模擬形式例如，使用一種儀表，儀表的指標的位置指明我們所感興趣的變數的大小或是以數字形式使用一套數字顯示元件，顯示對應於我們所感興趣的變數的數字。其它的可能的情況下是將輸出轉換成聲能利用揚聲器，或是將輸出作為另一個系統的輸入，或是利用輸出作為控制訊號來產生某個動作。
2
第二篇
The mathematics of computers and other digital electronic devices have been developed from the decisive work of George Boole l815～l864 and many others, who expanded and improved on his work. The body of thought that is known collectively as symbolic logic established the principles for deriving mathematical proofs and singularly modified our understanding and the scope of mathematics.
布林代數也稱為邏輯代數。它是英國數學家喬治-布林1815-1864於1849年創立的。在當時，這種代數純粹是一種數學遊戲。在布林代數裡，布林構思出一種關於0和1的代數係數，用基礎的邏輯符號系統描述物體和概念。這種代數不僅廣泛於概率和統計等領域，更為重要的是，它為數字計算機開關電路設計提供了最重要的數學方法。
Only a portion of this powerful system is required for our use. Boole and others were interested in developing a systematic means of deciding whether a proposition in logic or mathematics was true or false, but we shall be concerned only with the validity of the output of digital devices. True and false can be equated with one and zero, high and low, or on and off. These are the only two states of electrical voltage from a digital element. Thus, in this remarkable algebra performed by logic gates, there are only two values, one and zero; anyalgebraic combination or manipulation can yield only these two values. Zero and one are the only symbols in binary arithmetic.
這種很有用的系統中只有一部分內容為我們所應用。布林等人感興趣的是推匯出一種用來判斷某個命題在邏輯上或在數學上是真還是假的系統性的方法，但我們要關注的僅僅是數字裝置的輸出的正確與否。真或假可以等同於一和零 ，或者等同於開和關。這是電子元件中電壓的兩種唯一的狀態。因此，由邏輯閘所完成的這個奇異的代數中，只有兩種值，一和零，任何代數組合或者計算只能產生這兩種值。零和一是二進位制運算中唯一的符號。
The various logic gates and their interconnections can be made to perform all the essential functions required for computing and decision-making. In developing digital systems the easiest procedure is to put together conceptually the gates and connections to perform the assigned task in the most direct way. Boolean algebra is then used to reduce the complexity of the system, if possibl，ewhile retaining the same function. The equivalent simplified combination of gates will probably be much less expensive and less difficult to assemble
不同的邏輯閘和它們之間的相互連線可以用來完成計算以及判斷所要求的必要的功能。在開發數字系統時最簡單的做法是把邏輯閘以及它們之間的連線根據概念排放在一起 以最直接的方式完成 設定的任務。於是我們採用布林代數來減小系統的複雜程度，如果可能的話，與此同時應保留其相同的功能。邏輯閘之間等效的簡單的組合可能使得費用更加便宜而在裝配上更加容易。
Boolean algebra has three rules of combination, as any algebra must have: the associative, the commutative, and the distributive rules. To show the features of the algebra we use the variables A, B, C, and so on. To write relations between variables each one of which may take the value 0 or l, we use to mean “not A,” so if A = l , then = 0. Thecomplement of every variable is expressed by placing a bar over the variable; the complement of
= "not B". Two fixed quantities also exist. The first is identity, I = l; the other is null, null = 0
布林代數與任何代數一樣具有結合律、交換律和分配律。為了表示代數的特性我們使用變數A,B和C以及諸如此類的變數。為了寫出這些可能取值為0或1的各個變數之間的相互關係，我們採用來ā表示“非A”，因此如果A=1，那麼ā=0。每個變數的補碼用每個變數上方加一橫線來表示，B的補碼就是ā也即“非B”。同時還存在兩個固定的量。第一個量是單位量，即I=1，另外一個量是零，即null=0。
Boolean algebra applies to the arithmetic of three basic types of gates: an OR-gate, an AND-gate and the inverter. The symbol and the truth tables for the logic gates are shown in Fig.2-3, the truth table illustrate that the AND-gate corresponds to multiplication, the OR-gate corresponds to addition, and the inverter yield the complement of its input variable.
布林代數應用於三種基本型別的邏輯閘的運算：一種是或門，一種是與門，還有一種是反相器非門。邏輯閘的符號和真值表如圖2-3所示，真值表顯示與門對應於乘，或門對應於加，而反相器產生其輸入變數的補碼
We have already found that AB = "A AND B" for the AND-gate and A + B = "A OR B" for the OR-gate我們已經算出對於與門來說 AB=“A AND B”而對與或門來說 A+B=“A OR B”
The AND, or conjunctive, algebraic form and the OR, or disjunctive, algebraic form must each obey the three rules of algebraic combination. In the equations that follow, the reader may use the two possible values 0 and l for the variables A, B, and Cto verify the correctness of each expression. Use A = 0, B = 0, C = 0; A = l, B = 0, C = 0; and so on, in each expression. The associative rules state how variables may be grouped.
對於“與”，即邏輯乘，以及“或”，即析取，它們的代數形式必須遵循代數組合的三個法則。在接下來的等式中，讀者可以把變數A,B,C設為兩個可能的值0和1來證明每個表示式的正確性。例如採用A=0,B=0,C=0，或A=1, B=0,C=0等等，在每個表示式中，結合律表明如何把變數進行重組
For AND ABC = ABC = ACB,
and for OR A + B + C = A + B + C = A + C + B
對於“與”有ABC=ABC=ACB而對於“或”有A+B+C=A+B+C=A+C+B
the rules indicate that different groupings of variables may be used without altering the validity of the algebraic expression這個法則表明我們可以採用變數的不同組合而不改變代數表示式的正確性。交換率表明了變數的順序
The commutative rules state the order of variables.
For AND AB = BA
and for OR A+B = B+A
the rules indicate that the operations can be grouped and expanded as shown
對於“與”有AB=BA，而對於“或”有A+B=B+A。這個法則表明了可以如上式所示進行運算的組合和展開
Before we show the remaining rules of Boolean algebra for digital devices, let us confirm the distributive rule for AND by writing the truth table, Table 2-l. We will discover soon how we knew that we could write AB + C = A + CB + C, which is proved by the truth table to be a proper expansion.
在我們展示數字裝置布林代數的剩下的那個法則之前，讓我們通過寫出真值表的方式即真值表2-1來驗證對於“與”的分配律。我們將很快發現如何寫出等式AB+C=A+CB+C，這一等式由真值表證明了是一個正確的展開式。
The more complex expression and its simpler form yield identical values. Because binary logic is dominated by an algebra in which a sum of ones equals one, the truth table permits us to identify the equivalence among algebraic expressions. A truth table may be used to find a simpler equivalent to a more complex relation among variables, if such an equivalent exists. We will see shortly how the reduction of complexity may be achieved in a systematic manner with truth tables and other techniques.
更為複雜的表示式和它的一次式產生了相等的值。由於二進位制邏輯取決於某一代數，其單個變數之和等於一個變數，所以真值表允許我們在代數表示式中找出等效值，我們可以使用真值表來求出一個等效於變數之間較複雜的關係式的一次表示式。如果這樣的等效關係存在，我們將很快看到利用真值表以及其它方法以一種系統性的方式如何完成這樣一個複雜步驟的簡化工作。
Some additional relations in the algebra, which use identity and null, are worth nothing. Here we illustrate properties of the AND and OR operations that use the distributive rules and the fact that I is always l and null is always 0.
AND
OR
AND
OR
AND
OR
AND
OR AI = A or A1 = A A+ null = A A + 0 = A A = null A = 0 A + = I A + =1 A null = null A0 = 0 A + I = I A + 1 = 1 AA = A A + A = A
The relation points out an important fact, that is, that I, the identity, is the universal set. Null is called the empty set.
代數中另外的一些關係式，這些式子中使用單位一和零，是沒有意義的，這裡我們列舉了運用分配律後“與”和“或”運算的性質，結果是1永遠是1而零永遠是0。
與：AI=A即A1=A
或：A+null=A即A+0=A
與： 即
或： 即
與：Anull=0即A0=0
或：A+I=I即A+1=1
與：AA=A
或：A+A=A
關係式A+A=I指出了一個重要事實，即I，也就是單位量，是全集，而零被稱為空集。 We have considered several logical relations. For the two-value Boolean algebra of digital electronics, the choice of the technique depends upon the nature of the function whose reduction is desired. Some simple functions may be easily reduced by examining their truth table; others require the manipulation of Boolean algebra to reveal the relationship . When we consider the circuit foradding binary numbers, we see that Boolean algebra is required to discover a simplification in that particular application
我們已經研究了幾種邏輯關係。對於電子學的二值布林代數來說，選擇何種方法取決於我們所期望的簡化函式的性質。一些簡單的函式可以通過觀察它們的真值表很容易進行簡化;而另一些函式需要通過計算布林代數來揭示它們的關係。當我們研究有關二進位制數相加的電路時，我們將看到需要布林代數來揭示該特定應用中的簡化過程