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一、引言所谓数字复接是把若干较低速率的数字信号,按予定帧结构合并成一个较高速率的数字信号,这是一种基于时分原理的多路复用技术。按照时钟匹配,可分同步复接、异步复接和准同步复接;根据合路信号,又分路复接和群复接;依复用结构的不同,还有比特复接、码字复接和成帧比特复接之分。数字复接与数字传输、数字交换一起构成数字网的重要组成部分,在各种大容量通信系统以及未来的综合业务数字网(ISDN)中,将获得广泛的应用。准同步复接是指参与复接的各支路数字信号,具有相同的标称速率并保持一定的容差。
I. Introduction The so-called digital multiplexing is the number of lower-rate digital signals, according to the predetermined frame structure into a higher rate of digital signal, which is based on the principle of time-division multiplexing. In accordance with the clock matching, can be divided into synchronous multiplexing, asynchronous multiplexing and quasi-synchronous multiplexing; according to the combined signal, and multiplexed and multiplexed splitter; according to the different multiplexing structure, there are bit multiplexing, code complex Access and framing bit multiplexed points. Digital multiplexing and digital transmission, digital switching together constitute an important part of the digital network, in a variety of high-capacity communications systems and future integrated services digital network (ISDN), will be widely used. Plesiochronous multiplexing refers to the digital signal of each branch participating in multiplexing, having the same nominal rate and maintaining a certain tolerance.