摘要
高比特率数字用户环路技术是在光纤用户网普及之前，向用户提供宽带业务的一种过渡手段。DMT（离散多音频调制）是一种多载频调制，由于性能优越，被广泛应用于HDXSL和ADSL系统中。采取回波抵消的方法，可以提高系统传输速率、增加传输距离。本文着重介绍了基于DMT的HDSL和ADSL系统中的回被抵消技术─—TAFDEC（TimeandFrequencyDomainEchoCanceler）方法，即将频域的回波抵消器（EC）和时域的回波会成器（CES）结合起来，以达到减少运算量，降低复杂度的目的。并在此基础上，介绍一种改进结构，进一步降低复杂度。
The high-bit-rate digital subscriber line technology used to be a transitional means to provide subscribers with broadband sefores prior to the popularization of light-fiber subscriber networks. With its superior performance, DMT, a kind of multicarrierfrequency modulation, has found wide applications in HDSI, and ADSL Systems. In addition, the echo cancellation method can ellhance the transmission rate of the system and lengthen the distance of transhassion. This paper aims to give an introduction of the echo. cancellation technology in the DMT-based HDSL and ADSL system, of the TAFDEC (Time and Frequency Domain Echo canceller) method, which combines the frequency domain echo canceller (EC) with the time domain echo canceller (CES) to achieve the qurpose of lessening operations and reducing complexity.An imprond scheme that can further reduce complekity is then proposed.
出处
《数字通信》
1997年第2期30-32,共3页
Digital Communications and Networks
