自动化专业英语考试

Unit 3

A: Logical Variables and Flip-flop

逻辑变量和触发器

Logical Variables

逻辑变量

原文[1]

The two-valued variables which we have been discussing are often called logical variables, while the operations such as the OR operation and the AND operation are referred to as logical operations. We shall now briefly discuss the relevance of such terminology, and in so doing we shall bring out the special aptness of the designations “true” and “false “ to identify the possible values of a variable.

注释

two-valued variables 双值变量

operation 运算

be referred to as 被认为是…,称为

relevance 关联

terminology 术语

in so doing 这样做时（在这种情况下）

bring out 提出，阐明

aptness 恰当

designation 标识

参考译文

我们讨论的双值变量通常叫做逻辑变量，而像或和与这样的操作被称为逻辑操作。现在我们将简要地讨论一下这些术语之间的关联，并在此过程中，阐明用标识“真”和“假”来区分一个变量可能值的特殊用途。

原文[2]

By way of example, suppose that you and two pilots are aloft in an airplane. You remain in the cabin, while the pilots, A and B, are in the cockpit. At some time, A joins you. This development causes you no concern. Suppose, however, that while you and A are in the cabin, you look up to find that B has also joined you. On the basis of your ability to reason logically you deduce that the plane is pilotless; and, presumably you sound an alarm so that one of the pilots will respond promptly to the urgency of the situation.

注释

by way of…以…的方式

by way of example （以例子的方式）举例说明

aloft 高高地

cabin 客舱

cockpit 坐舱，驾驶舱

on the basis of …基于，根据…

deduce 推理，推断，演绎

presumably 很可能，大概，想必是

promptly 迅速地，敏捷地

参考译文

举例说明，假设你和两个飞行员在一架空中航行的飞机中，你在客舱中，而飞行员A和B在驾驶员座舱中。在某一时刻，A来到了你所在的客舱中，你并不担心这种变化。然而，假设当你和A 在客舱时，你抬头发现B 也已经来到了你所在的客舱中。基于你的逻辑推理能力，你将会推断飞机无人驾驶；并且，大概你已听到了警报，以致使驾驶员之一将迅速对此紧急情况作出响应。

原文[3]

Alternatively, suppose that there had been attached to each pilot’s seat an electronic device that provided an output voltage which is V1 when the seat is occupied and V2 when the seat is not occupied. Let us attach the designation “true” to the voltage level V2 so that the level V1 is “false”. Let us further construct an electric circuit with two sets of input terminals and one set of output terminals. The circuit is to have the property that the output voltage will be V2 if and only if both inputs, i.e., one input AND simultaneously the other, are at the level V2. Otherwise the output is V1.

注释

alternatively 换句话说

attached to 与…相连

occupy 占据，使用

attach A to B 使A与B有联系，使A与B有关联

construct 构造，建造

set of …一组，一套，一副…

terminal （电路的）端子，线接头

i.e. that is to say…

simultaneously 同时地

参考译文

换句话说，假设每一位飞行员座位下面有一个电子装置，当座位上有人时，其输出电压为V1，当座位上无人时，其输出电压为V2。现在我们用“真”来代表电压V2，从而使电压V1表示“假”。让我们进一步制作一个带有两个输入端和一个输出端的电路，此电路的特性是：只要两个输入，即一个输入同时和另一个输入相与，结果为

V2时，输出电压才是V2。否则，输出是V1。

原文[4]

Finally let us connect the inputs to the devices on the chairs of pilots A and B and arrange that an alarm bell, connected to the output Z, respond when the output is V2 (“true”) and not otherwise. We have then constructed a circuit which performs the AND operation and is capable of making the logical deduction that the plane is unpiloted when, indeed, both pilots leave the cockpit.

注释

logical deduction 逻辑判断，逻辑演绎

参考译文

最后，让我们把输入和飞行员A 和B 座位下的装置联结起来，并安装一个与输出Z相连的警铃，当输出是V2 (“真”)时响应，否则不响应。这样，我们已创建了一个执行与操作的电路，这个电路能完成当两个驾驶员确实都离开驾驶舱时飞机是无人驾驶的逻辑推断。