以頻域為基準之時域等化器運用於數位用戶迴路之設計

Abstract

離散多調(DMT)已經成功應用於數位用戶迴路(DSL)上。在數位用戶迴路的應用上,通道長度太長時,會加入時域等化器(TEQ)來縮短等效通道長度並降低干擾。另外,等化過後通道的頻率響應對傳輸率也有重要的影響。特別是當零點發生在傳輸頻帶時,會造成傳輸率的下降。在論文中, 我們提出一個以頻域為基準的等化器設計方法來降低頻率上的干擾。這個方法考慮到了等化過後通道的頻率響應。最後,我們模擬極高速數位用戶迴路(VDSL)來說明這個方法的效果。從模擬可以看出這個等化器可以有效地改善傳輸率。

The Discrete MultiTone system has been successfully applied to Digital Subscriber Lines (DSL) system. For DSL applications, the channels length are generally very long and a Time Domain Equalizer (TEQ) is usually used to shorten the effective channel and mitigate interference. On the other hand, the frequency response of the equalized channel is crucial for determining transmission bit rate. In particular, zeros in the transmission bands often results in a loss in bit rate. In this thesis, we proposed a novel frequency domain based TEQ design. Interference is minimized in the frequency domain. This method takes into account the frequency response of the equalized channel implicitly. We will use Very-high speed Digital Subscriber Line system as an example to demonstrate the usefulness of the proposed method. Simulation examples show that the frequency domain based TEQ have very good bit rate.