一、数字通信系统的构成 通信的任务是由一整套技术设备和传输媒介所构成的总体──通信系统来完成的。电子通信根据信道上传输信号的种类可分为模拟通信和数字通信。数字通信系统设备多种多样，综合各种数字通信系统，其构成如图１所示。 图１中，信源把信息变成原始的电信号? First, the composition of digital communication system The task of communication is composed of a complete set of technical equipment and transmission media, the overall ─ ─ communication system to complete. Electronic communication according to the type of signal transmission channel can be divided into analog communications and digital communications. Digital communication system equipment variety, a variety of integrated digital communication system, its composition shown in Figure 1. In Figure 1, the source of the information into the original electrical signal?