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二、蜂窝式移动电话制式及其工作原理蜂窝式移动电话依其技术特点,有模拟制和数字制两大类。模拟制主要是指话音用模拟信号传输。系统的控制信令多为模拟单音,但也有部分为数字式,以频键控(FSK)调制传输,以频分多址(FDMA)方式复用的。数字制有时分多址(TDMA)和码分多址(CDMA)之分。目前广为使用的 GSM 系统即为 TDMA 制
Second, the cellular mobile phone standard and its working principle Cellular mobile phones according to their technical characteristics, analog and digital systems are two categories. Analog system mainly refers to the voice of the analog signal transmission. Most of the system control signaling is analogue tones, but some are digital, modulated by frequency-shift keying (FSK) and multiplexed by frequency division multiple access (FDMA). Digital system with time division multiple access (TDMA) and code division multiple access (CDMA) points. Currently widely used GSM system is TDMA system