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随着北京电信长城移动通信CDMA实验网的开通,国内手机通信系统在经历了模拟、GSM数字系统的变革之后,在1997年10月又迎来了码分多址技术——CDMA数字蜂窝移动通信系统的时代。 目前CDMA技术在北美、亚太地区已被大规模投入商用,在美国的移动通信市场上,CDMA手机已成为购机者的首选目标。CDMA系统这个后起之秀之所以一面世就受到大家的欢迎,得益于它独特的工作方式。众所周知,以前的模拟手机只能在模拟网覆盖的地区使用,GSM手机只能在GSM网覆盖的地区使用,两大系统互不支撑,不但给使用者带来了一定的局限性,也给整个无线通信系统造成了一定的资源浪费。采用CDMA技术的新型手机由于实行的是双模式,所以无论是在数字网覆盖的地区还是在模拟网覆盖的地区,都能自动转换工作方式,因此给其手机的使用者带来了更多的方便。再加上它公认的通话质量高——接近市话效果、对人脑辐射小——发射功率在0.1mW到200mW之间、掉话率低、保密
With the opening of Beijing Telecom Great Wall Mobile CDMA Experimental Network, after experiencing the revolution of analog and GSM digital system, the domestic mobile phone communication system ushered in the code division multiple access technology - CDMA digital cellular mobile communication The era of the system. At present, CDMA technology has been put into large-scale commercial applications in North America and Asia Pacific regions. CDMA mobile phones have become the preferred target of purchasers in the U.S. market of mobile communications. The reason why the rising star of the CDMA system has been welcomed by everyone, thanks to its unique way of working. As we all know, the former analog handsets can only be used in areas covered by the analog network. The GSM handsets can only be used in areas covered by the GSM network. The two systems do not support each other. This not only gives the user some limitations but also gives the entire Wireless communication system caused a certain amount of waste of resources. Since the new handsets using CDMA technology are dual mode, they automatically switch their working mode whether they are in the area covered by the digital network or the area covered by the analog network, thereby bringing more users of their handsets Convenience. Coupled with its recognized high call quality - close to the local effect, radiation on the human brain is small - launch power of 0.1mW to 200mW, call drop rate is low, confidential