数字用户环路（0十4）的实现

Achievement of digital subscriber loop (0+4)

介绍了利用现有的用户线路，采用回波抵消和均衡技术，在一普通的２线用户线上实现全双工传输２Ｂ十Ｄ数字信号，即数字用户环路（０＋４）的具体方法。此方案易于实现，可在１对用户线上传输４路用户信号，能节省投资，且信号传输质量高，是当前缓解用户线路紧张状态的一种良好措施．

Using old subscriber lines, the full duplex transmission over a single twisted pair can be done by adaptive echo cancellation and adaptive equalization, then signals of four loops can be transmitted over a single pair. A specific method to achieve the digital subscriber line (0+4) on the basis of above-mentioned technology is provided. The method is easy to be used, the signals transmitted have a good quality. And a great amount of funt can be saved. It is a good way to solve the problem of loops in short supply.