非對稱性分散式多波道系統下的回音消除速率轉換

Abstract

中文摘要 在分散式多波道系統長封包傳輸下，鄰近封包間容易互相產生干擾，所以在迴音消除處理上，我們可先行在時域上的補償等化器，部分處理掉彼此封包互相干擾的成分，再經由頻域上的迴音通道等化器來做完整地迴音消除，如此與傳統單一時域或頻域等化器上做比較，可在運算複雜度上減少許多。而對於非對稱性的多波道系統傳輸，傳送端與接收端的速率必須做轉換匹配後，才可進一步地做迴音的消除處理。在這裡，我們除了作深入的探討外，並對於內插訊號取樣的方式，提出一個在計算上可較簡化的方式，即利用分相式型態，來減少運算複雜度。

Abstract Due to I.S.I. (Intersymbol Interference) between adjacent blocks for ADSL based on DMT (Discrete Multitone), we can corresponsively use tail cancellation and cyclic reconstruction in time domain and LMS algorithm in frequency domain for echo cancellation. When compared with traditional equalizer only in time domain or frequency domain, it would reduce the computing complexity. For ADSL, the rate conversion between transceiver and receiver must match before echo cancellation. In the thesis, we research the rate conversion and expand interpolation, poly-phase form, for reducing the computing complexity.