编者按 随着社会、经济的高速发展，现代通信已经在人们生活中占据了必不可少的重要地位。我们有必要对通信系统以及现代通信网加以了解。本系列讲座共有十二讲，分三大部分，即现代通信网络的组成、现代通信网络技术和现代通信网络中的信息传输技术，系统地介绍现代通信网技术。 Editor’s note With the rapid social and economic development, modern communication has occupied an essential and important position in people’s lives. We need to understand the communication system and the modern communication network. This series of lectures consists of 12 chapters, divided into three parts, namely the composition of modern communication network, modern communication network technology and modern communication network information transmission technology, a systematic introduction of modern communication network technology.