10 词条
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2G wireless network
Second-generation (2G) digital cellular networks used by mobile phones. 2G networks was developed as a replacement for first generation (1G) analog cellular networks, and the GSM standard originally described a digital, circuit-switched network optimized for full duplex voice telephony. This expanded over time to include data communications, first by circuit-switched transport, then by packet data transport via GPRS (General Packet Radio Services) and EDGE (Enhanced Data rates for GSM Evolution or EGPRS).
2G wireless network的贡献者
2G wireless network
扩频
移动通信; 2G wireless network
传输信息时所用信号带宽远大于传输此信息所需最小带宽的一种信号处理技术。发射端展宽频带是用独立于所传数据的码来实现，接收端用同步的相同码解扩以恢复所传数据。扩频的基本方法有，直接序列(DS)、跳颁(FH)、跳时(TH)和线性调频(Chirp)等4种，扩频的主要特点为。抗干扰，抗多径衰落，低截获概率，码分多址能力，高距离分辨率和精确定时特性等。 ...
失步系数
移动通信; 2G wireless network
位同步环路中，若通信过程信号暂时中断，原处于锁定状态的环路将失去控制。由于收发两端同步振荡器存在频差，位同步信号就会相对输入信号相位偏移，通常对提出不超过某个允许值的要求。 ...
