英文翻譯(編輯修改稿)

　

【文章內容簡介】 d railway is mainly to carry passenger, so it will not speed up the turnover rate between cargos and the capital and will not decrease the costs of the whole social build such a large network of highspeed rail will need a large amount of money, the government must increase the taxes of people and enterprise to raise the this financial investment used in health care, social security, education, tec第三篇：英文翻譯Overview of the Global System for Mobile Communications 1 History of GSM During the early 1980s, analog cellular telephone systems were experiencing rapid growth in Europe, particularly in Scandinavia and the United Kingdom, but also in France and country developed its own system, which was inpatible with everyone else’s in equipment and was anundesirable situation, because not only was the mobile equipment limited to operation within national boundaries, which in a unified Europe were increasingly unimportant, but there was also a very limited market for each type of equipment, so economies of scale and the subsequent savings could not be Europeans realized this early on, and in 1982 the Conference of European s Posts and Telegraphs(CEPT)formed a study group called the Group Special Mobile(GSM)to study and develop a panEuropean public land mobile proposed system has to meet certain criteria: Good subjective speech quality Low terminal and service cost Support for international roaming Ability to support handheld terminals Support for range of new services and facilities Spectral efficiency ISDN patibility In 1989, GSM responsibility was transferred to the European Telemunication Standards Institute(ETSI), and phase I of the GSM specifications were published in service was started in mid1991, and by 1993 there were 36 GSM networks in 22 standardized in Europe, GSM is not only a European 200 GSM networks are operational in 110 countries around the the beginning of 1994, there were million subscribers worldwide, which had grown to more than 55 million by October North America making a delayed entry into the GSM field with a derivative of GSM called PCS1900, GSM systems exist on every continent, and the acronym GSM now aptly stands for Global System for Mobile developers of GSM chose an unproven(at the time)digital system, as opposed to the thenstandard analog cellular systems like AMPS in the United States and TACS in the United had faith that advancements in pression algorithms and digital signal processors would allow the fulfillment of the original criteria and the continual improvement of the system in terms of quality and over 8,000 pages of GSM remendations try to allow flexibility and petitive innovation among suppliers, but provide enough standardization to guarantee proper interworking between the ponents of the done by providing functional and interface descriptions for each of the functional entities defined in the General Concepts Analog Versus Digital Telephony Systems Firstgeneration systems were the early 1980s these underwent rapid development in the NMT system was used by all the Nordic countries, and the TACS system in the United Kingdom and Italy, there was a variety of systems and no patibility among with these systems, the main advantages offered by GSM, which is the most important of the secondgeneration digital systems, are: Standardization。Capacity。Quality。 guarantees patibility among systems of different countries, allowing subscribers to use their own terminals in those countries that have adopted the digital lack of standardization in the firstgeneration system limited service to within the borders of a is improved, since roaming is no longer limited to areas covered by a certain can be charged and handled using the same personal number even when the subscriber moves from