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所谓第三代移动通信系统是指相对于第一代采取模拟技术的移动通信系统和采用数字技术的第二代移动通信系统而言的。第一代移动通信系统制式繁多,世界各国所采用的制式也不相同,北美和澳大利亚采用AMPS,英国采用TACS、瑞典等国采用NMT450、NMT900。意大利等采用RTMS,法国采用RC2000,而我国主要采用TACS和AMPS两种制式。第二代移动通信系统也有几种不同的制式,主要有欧洲的GSM和北美等国的DAMPS和CDMA等。目前我国广泛应用的是GSM系统。而CDMA也已在我国五个主要城市建网使用,并在逐步发展扩大其使用范围。从移动通信技术发展的进程看、尽管第二代移动通信系统实现了从模拟技术向数字技术的转变,但由于制式的不同,
The so-called third-generation mobile communication system refers to the first generation of analog technology to take the mobile communication system and the use of digital technology in terms of the second generation of mobile communication systems. The first generation of mobile communication system has many formats, and the systems adopted by different countries in the world are not the same. AMPS is adopted in North America and Australia, TACS is used in Britain, and NMT450 and NMT900 are used in Sweden and other countries. Italy, etc. using RTMS, France using RC2000, and our main use of TACS and AMPS two formats. The second generation of mobile communication system also has several different formats, mainly in Europe, GSM and North American countries such as DAMPS and CDMA. At present, China is widely used GSM system. CDMA has also been used in five major cities in China, and is gradually expanding its scope of use. From the perspective of the development of mobile communication technology, although the second generation mobile communication system has realized the change from analog technology to digital technology, due to the difference of the standard,