专业英语复习试题及答案15-16单元

15-16单元复习题目及答案一、T ranslate the following words into English.时分同步码分多址第三代伙伴计划全球移动通信系统上行链路吞吐量部署国际电信联盟时分双工远程（信息）处理多路存取全球移动通信系统陆地无线接入信令协议反馈间歇的外围设备缓冲存储器无缝服务外场测试软切换二、Translate the following words and expressions into Chinese.Pedestrian compatible traffic asymmetric UMTSHarmonization inventory are called upon to macro cellMcps kbps HCR time-shared computers private networkscell breathing effect multiplexed connections三、Fill in the blanks with suitable words from the list given below.The most applicable model for data communications requirements is the central computer with many simple terminals simultaneously. Differing from telephone communications, a data communications network must be able to a wide variety of subscriber’s equipment. Several different types of computer peripherals may appear as network terminals, and so also can computers functioning in several different ways. Terminal speedsfrom 100 bits per sec to 10,000 bits per sec are likely to be important. Many terminals in current use are by the available communications services, but many of them have variable speeds. One approach to this situation is to provide a store at the terminal, but this approach is expensive.Rec ranging buffer constrained interconnect conversing四、Comprehension. choose the best answer according to this passage.The rapid growth of data communications has been influenced primarily by the increasing need to move information to and from computers. Modern time-shared computers can communicate with many data stations simultaneously. Other forms of data transmission which the telephone and telegraph lines are called upon to handle are batch data transmission, real-time transmission (as in the case of airline reservation systems), banking and credit data, man-computer conversation with the aid of graphics, data collection systems and automatic meter reading. The combination of computers and data communication places such new requirements on the systems, which must handle them, that one can refer to them better as teleprocessing rather than telecommunications.[1] Teleprocessing started with the airline reservation systems, where the distribution of computer data is not as important as the maintenance of an inventory of seats for the whole system and the ability to access such an inventory rapidly at a number of distant points. Another example is that of the banks, who desired to centralize their accounting and provide access to a central file for all their branches. Basically, there are three reasons for the development of teleprocessing systems: the requirement for centralized files, the need to distribute computer services and the advantage gained by having flexibility in location of the operating staff which utilizes the system.Initially, both the airline and banking operations can be established on a private basis, which would minimize the need for switching operations. But in both cases, the need to expand beyond private operations soon arises. In the case of the airlines, the need arises to access the facilities of other airlines; and in the case of the banks, certain common data facilities may be shared with other banks. Even though private networks may suffice for many services, the need to provide data communications between urban centers leads to regional and national networks. In the U.S., the Bell System, the independent telephone companies and specialized data communication networks are involved as carriers of such data.1. The rapid growth of has been influenced primarily by the increasing need to move information to and from computers.A. data stationsB. data communicationsC. data transmissionD. Telecommunications2. Modern computers can communicate with many data stations simultaneously.A. real-timeB. privateC. time-sharedD. common3. Teleprocessing started with the airline systems.A. reservationB. inventoryC. maintenanceD. accounting4. One of the three reasons for development of teleprocessing systems is the advantage gained by having in location of the operating staff which utilizes the system.A. flexibilityB. communicationC. memoriesD. Feedback5. The need to provide data communications between urban centers leads to .A. regional networksB. national networksC. Both A and BD. telecommunications.五、T ell whether the following statements are true(T) or false(F) according to the passageAt present, multi-access computers usually handle terminals of only one speed or with a small number of fixed speeds. It has been proposed that feedback from the output device be used to permit one simple output program to drive terminals with different characteristics. Of course, such feedback signals would have to be handled by the communications network.At data technology develops, each multi-access computer is connected to an increasing number of terminals, making it expensive and difficult to provide separate lines from the computer to the network for each of the terminals. Thus, a need for multiplexed connections between the computer and the terminals arises. But this need cannot necessarily be met in a straightforward manner. One characteristic of a data communications network differing from conventional telephone networks is that the two ends of the communication link are very different. One end is a computer capable of flexible behavior, and the other end is a relatively slow terminal with no intelligence. Since the two ends are so different, it would appear that the network would communicate differently with them. The flow of information in a data communication system is intermittent just as it is in the case of telephone conversations. However, instead of minutes of conversation, only a few seconds will elapse for the information flow in one direction, followed by a pause and some flow of information in the opposite direction. The access times for typical computers in use at this time are about 100 ms, but this will become faster as better memories are utilized. The time scale for the interchange of data messages needs to be of this order.1、It has been proposed that feedback from the input device be used to permit one simple output program （）2、Each multi-access computer is connected to an increasing number of terminals, making it expensive and difficult to provide separate lines from the computer to the network for each of the terminals.（）3、A need for multiplexed connections between the computer and the terminals decreases（）4、The flow of information in a data communication system is intermittent （）5、The access times for typical computers in use at this time are about 1000 ms六、T ranslate the following sentences into Chinese.1、TD-SCDMA adapts the uplink/downlink ratio according to the data load within a single unpaired frequency thus utilizing the spectrum more efficiently.2、Highly effective technologies like smart antennas, joint detection and dynamic channel allocation -which are integral features of the TD-SCDMA radio standard-contribute to minimize intra-cell interference (typical of every CDMA technology) and inter-cell interference leading to an outstanding spectrum efficiency (3-5 times GSM).3、 3G services are introduced adding TD-SCDMA radio subsystems to existing stable and established GSM infrastructures. The total migration costs from 2G to 3G decrease considerably, compared to other 3G standards.4、TD-SCDMA uses conventional handover (similarly to GSM) which leads to a sensible reduction of the cost of leased lines compared with other 3G standards.5、In the second release of the UTRA standard (called Release 4, March 2001), 3GPP agreed upon the worldwide harmonization and extension of the TDD performance spectrum. Additional features of TD-SCDMA radio technology were also included in the specification for this UMTS Standard (Figure 16.2).6、TDDLCR uses the UTRA core network and the TD-SCDMA air interface. It is also possible, however, to introduce a TD-SCDMA Radio Access Channel while using the GSM core network, including the signaling and protocols (Figure 16.4).答案：一、 Time Division Synchronous Code Division Multiple Access（TD-SCDMA）、 the Third Generation Partnering Project (3GPP)、Global system for mobile communication（GSM） uplinkthroughput deploy International Telecommunication Union （TUI）Time Division Duplex teleprocessing multi-accessthe UMTS terrestrial radio access signaling protocol feedback intermittent peripheral buffer store seamless services Field Trials soft handover二、步行者能兼容的话务量不对称的全球移动通信系统一致清单用来....... 宏小区兆码片每秒千比特每秒高码片速率时分计算机专用网络小区呼吸效应复用连接三、conversing interconnect ranging constrained buffer四、1、B 2、C 3、A 4、A 5、 C五、1、F 2、T 3、F 4、T 5、 F六、1、P189（倒数第四行开始） 2、P190（第七行开始） 3、P190（第十四行开始） 4、P190（倒数第四行开始） 5、 P192（第五行开始） 6、P192（倒数第二行开始）。