歐規數位電視地面/手持廣播基頻接收機之設計與實作

Abstract

本論文探討歐規數位電視地面/手持廣播系統(DVB-T/H)之特色與規格。此外，基頻通道模型在本論文中也予以討論，其中通道效應包含多路徑衰減通道(Multipath Fading Effect)、加成性白色高斯雜訊(AWGN)、載波頻率漂移(Carrier Frequency Offset)、取樣時脈漂移(Sampling Clock Offset)、以及相位雜訊(Phase Noise)。根據此規格以及通道模型，本論文提出一基頻接收機，包含各模組之演算法，電路設計，以及硬體實做。為了支援移動接收之機能，本論文提出一通道估測及補償之演算法，並結合一兩階段模式偵測、符元時間偵測、載波頻率漂移與取樣時脈漂移之估測、補償及追蹤、2/4/8K FFT處理器、相位調整、軟性輸出解映射器及軟性輸入維特比解碼器。此外，為了降低系統之複雜度，於模式增測及整數載波頻率漂移之估測等處予以硬體簡化。為了解調傳輸參數訊號，一BCH解碼器也於本論文提出及設計。透過輸出訊噪比(Output SNR)取代位元錯誤率(BER)來做為決定最佳位元數之指標，進行全系統之定點數模擬。最後經由全系統之效能模擬及全系統之Verilog RTL程式之實做與驗證，證明本論文所提出之DVB-T/H基頻接收機之良好效能。

In this thesis, the features and specification of Europe DVB-T/H standard have been delineated. Besides, a baseband channel model has been discussed, including multipath fading effect, AWGN, CFO effect, SCO effect, and phase noise. Based on the standard and a baseband equivalent channel model, a baseband receiver is proposed, including algorithms, circuit design and Verilog RTL code implementation. To support mobile reception, this thesis proposes the channel estimation and equalization algorithm and combines algorithms of a two-stage mode detection, symbol timing detection, CFO as well as SCO estimation and compensation, 2/4/8K FFT processor, phase modification soft-output de-mapper and soft-input Viterbi decoder. In addition, to reduce the hardware complexity, the GI mode detection module and integer CFO module have been modified; to decode the TPS signal, a BCH decoder is designed and implemented as well. Through output SNR instead of bit error rate (BER) as the metric of the word-length determination, the optimal word-length can be obtained. By means of system performance simulation and verification of whole Verilog RTL code, the proposed DVB-T/H baseband receiver is proven to work well.