美規數位電視接收機適應性半盲目等化器的設計與製作

Abstract

克服多重路徑效應是實現地面廣播數位電視系統的一項關鍵技術。一般而言，克服多重路徑效應的有效方法有兩種技術。一種是目前應用在歐規數位電視系統DVB-T的正交分頻多工(Orthogonal Frequency Division Multiplexing ;OFDM)技術，而另外一種則是應用在美規數位電視系統的適應性等化(或稱鬼影消除)技術。多重路徑效應包含三種型態，也就是靜態多重路徑效應、 動態多重路徑效應、及快速動態多重路徑效應。因此，只靠訓練序列來追蹤多重路徑通道是不足夠的。 在本論文中，我們提出一種可以應用於美規數位電視系統的適應性半盲目決策迴授等化器設計架構。這個適應性半盲目決策迴授等化器是以決策迴授等化器為基礎。在這個適應性半盲目決策迴授等化器當中，我們利用結合訓練序列訊號及盲目演算法來估計多重路徑通道。而適應性調節機制利用訓練模式、直接決策模式及盲目模式分別來對抗上述的多重路徑效應。我們藉由模擬並提出適應性半盲目決策迴授等化器設計架構。除此之外，我們也完成了這個適應性半盲目決策迴授等化器的製作與測試工作。

It is a key technology to combat the multipath effect in realizing the digital terrestrial television broadcasting systems. In general, there are two effective techniques to combat the multipath effect. One is the OFDM technique for the EU DVB-T standard system and the other is the adaptive equalization technique (i.e. ghost cancellation) for the USA ATSC standard system. The multipath effect contains three categories, i.e. the static multipath effect, the dynamic multipath effect, and the fast dynamic multipath effect. It is not adequate enough to barely use the training sequence for tracking the multipath channel. In this thesis, we propose an adaptive semi-blind equalizer design architecture for the ATSC/DTV receiver. The adaptive semi-blind equalizer is based on a decision feedback equalizer. In this adaptive semi-blind equalizer, we combine the training sequence and the blind equalization algorithm to estimate the multipath channel. The adaptive scheme utilizes the training mode, the direct decision mode, and the blind mode to combat the aforementioned multipath effect. We simulate and propose adaptive semi-blind equalizer design architecture. In addition, we complete the implementation and the test work for the proposed adaptive semi-blind equalizer.