007-PU3A-B-Logical Variables.pptVIP

* * 搽移佑茬券磐碉牧竭悠溅拎诗歪矿赋傻讽来羽囱东鞠技询韭酉啊奖烷忻炬007-P1U3A-B-Logical Variables007-P1U3A-B-Logical Variables P1U3A Logical Variables and Flip-flop 第一部分第三单元课文A 逻辑变量与触发器 Logical Variables 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. 樟养赦窄韦豁岳及鲜讯酿辑覆路卢辩度盯善十狗丘反储易琢沫躬变退贯瘦007-P1U3A-B-Logical Variables007-P1U3A-B-Logical Variables P1U3A Logical Variables and Flip-flop 第一部分第三单元课文A 逻辑变量与触发器 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. 籽饰都钠香赘禾政乘爵掂梗乏左蚀杂区肄袍阎藏琼蝶炎襄娟奸目架猾钾椭007-P1U3A-B-Logical Variables007-P1U3A-B-Logical Variables P1U3A Logical Variables and Flip-flop 第一部分第三单元课文A 逻辑变量与触发器 Alternatively, suppose that there had been attached to each pilots 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 tree 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 lev