测控技术与仪器专业英语阅读翻译.docx

1、测控技术与仪器专业英语阅读翻译测控技术与仪器专业英语阅读翻译 5. Inheritance In Figure 9.7, the classes SalesOrderCheclcPmt and SalesOrderCreditPmt are called subclasses of SalesOrder. The class SalesOrder is called the super class of SalesOrderCheckPmt and SalesOrderCreditPmt. The relationship between a class and its subclass (o

2、r superclass) is called generalization or specialization. Subclasses inherit attributes and operations from their class. A subclass has its own additional attributes and operations. For example, the class SalesOrderCreditPmt inherits the attributes order No, order Date, delivery Date, and order Term

3、s and the methods calcTotal and changeDelivDate. In this case, the class SalesOrder is the generalized class, and SalesOrderCheckPrmt and SalesOrderCreditPrmt are the specialized classes. 6. Polymorphism Earlier it was mentioned that a DVR and a DVD player that respond similarly but differently to t

4、he same message are polymorphic. Polymorphism means having many forms. In the context of OQSAD, polymorphism means that the same message can invoke similar but different behavior. Thus, a message that invokes the operation calcTotalQ of a :SalesOrder object will result in the sales order total calcu

5、lation; a message that invokes the operation calcTotaIQ of a PurchaseOrder object will result in a purchase order total calculation. The implementation of the operations in the respective classes will be different. Foundations of the object model Structured design methods evolved to guide developers

6、 who were trying to build plex systems using algorithms as their fundamental building blocks. Similarly, object-oriented design methods have evolved to help developers exploit the expressive power of object-based and object- oriented programming languages, using the class and object as basic buildin

7、g blocks. Foundations of the object model. Actually, the object model has been influenced by a number of factors, not just object-oriented programming. The object model has proven to be a unifying concept in puter science, applicable not just to programming languages but also to the design of user i

8、nterfaces, databases, and even puter architectures. The reason for this widespread appeal is simply that an object orientation helps us to cope with the plexity inherent in many different kinds of systems. 5。继承 在图9.7中，类SalesOrderCheclcPmt和SalesOrderCreditPmt被称为SalesOrder的子类。类SalesOrder被称为超类SalesOrde

9、rCheckPmt和SalesOrderCreditPmt的。一类和它的子类（或超类）之间的关系被称为泛化或专业。子类继承他们的阶级属性和操作。子类有它自己的附加属性和操作。例如，类SalesOrderCreditPmt继承属性订单号，订单日期，发货日期和订单术语和方法calcTotal和changeDelivDate。在这种情况下，类SalesOrder是广义类，并SalesOrderCheckPrmt 和SalesOrderCreditPrmt是专门的类。 6.多态性 早些时候有人提到，DVR和DVD播放器，以相同的消息作出回应，但类似的不同是多态。多态是指“有多种形式”。在OQSAD的上

10、下文中，多态性是指同一消息可以调用类似，但不同的行为。因此，一条消息，调用的操作calcTotal：SalesOrder对象将导致销售订单总额计算;一个消息调用了一个采购订单对象的操作calcTotaL将导致采购订单总额计算。在各自的类中的操作的实现将是不同的。 对象模型的基础 结构化方法演变为指导开发谁试图建立使用的算法作为其基本构建模块的复杂系统。同样的，面向对象的设计方法已经发展到帮助开发人员利用基于对象和面向对象编程语言的表现力，使用类和对象的基本构建模块。对象模型的基础。 实际上，对象模型已经由许多因素的影响，而不是仅仅面向对象编程。对象模型已经被证明是一个统一概念在计算机科学中，适

11、用不只是为了编程语言，但也给用户接口，数据库，甚至计算机体系结构设计。这样做的原因广泛的吸引力仅仅是一个面向对象的帮助我们以应付所固有的许多不同种类的系统的复杂性。 当然，有应用的个人电脑的所有者可能想比仅通过GPIB与各种设备的奇数，提供更高的性能。这种系统通常称为基于PC的工作站。在基于PC的工作站，仪器模块匹配性能和兼容性都聚集围绕PC电脑。基于PC的工作站允许多台仪器的数据迅速聚集，存储，作图，分析，并纳入一台PC机上的报告形式。这种类型的系统一般都放在一个制造商合作，以提高性能和涉及的仪器模块之间的合作。 There are, of course, applications for

12、which the owner of a PC may want higher performance than that offered by the GPIB alone, with its odd assortment of devices. Such systems are generally referred to as PC-based workstations. In a PC-based workstation, instrument modules with matched performance and patibility are clustered around a P

13、C puter. The PC-based workstation allows data from multiple instruments to be rapidly gathered ,stored, graphed ,analyzed, and incorporated into report form on a single PC. Systems of this type are generally put together by one manufacturer to enhance performance and cooperation between the instrume

14、nt modules involved. 一个基于PC的工作站的一个例子是惠普推出的PC仪器系统。 PC仪器是一系列的九个专用仪器模块，旨在通过一个专门的接口总线操作惠普触摸屏II个人电脑，IBM PC / XT / AT，ATT的电脑6300，或的HP Vectra PC。在PC的仪器提供仪器模块是一个50 MHz的数字示波器，一个12位数字 - 模拟转换器双通道，100 MHz的通用计数器，5 MHz的函数发生器，数字万用表。 An example of a PC-based workstation is the PC Instruments system introduced by He

15、wlett-Packard. PC Instruments are a series of nine dedicated instrument modules designed to operate over a dedicated interface bus by an HP Touchscreen II personal puter ,an IBM PC/XT/AT, an AT&T PC 6300, or an HP Vectra PC. Among the instrument modules available for PC Instruments are a 50-MHz digi

16、tizing oscilloscope, a 12-bit dual-channel digital-to-analog converter, a 100-MHz universal counter, a 5-MHz function generator, and a digital multimeter. 从仪器模块收集的测试数据直接送入电脑存储，显示和分析。该仪器模块本身有没有米，或显示自己的。所有输出，包括波形显示，通过电脑屏幕上，可同时显示多达八个不同的仪器输出。 Test data gathered from the instrument modules are fed directly to the PC for storage, display, and analysis. The instrument modules