为了扩大传输容量和提高传输效率，需要进一步把若干个低速数字信号合并成一个高速数字信号，通过高速数字信道传输，到对方再分离、还原为各个低速数字信号。实现数字信号的合并与分离的技术称为数字复接与分接（简称数字复用），它是数字通信网的基础技术。前面我们讲过，一? In order to expand the transmission capacity and improve the transmission efficiency, it is necessary to further combine several low-speed digital signals into one high-speed digital signal, and then transmit the signals to the other side through high-speed digital channel to be re-separated to each low-speed digital signal. The realization of digital signal combining and separation technology called digital multiplexing and tap (referred to as digital multiplexing), which is the basis of digital communication network technology. We have talked about earlier, one?