摘要
數位電視系統非但能播放高品質的影像與聲音，而且，它也能傳送各式各樣的數位資訊。在21世紀，它將會成為嶄新的數位資訊傳播媒介，歐規數位電視的發展開始於1993年，我國數位電視系統採用歐規DVB-T 6MHz頻寬數位電視地面廣播標準，因為使用COFDM調變技術，所以具有建置SFN (Single Frequency Network)單頻網路廣播及行動接收功能。 在本論文裡歐規數位電視地面廣播的行動接收效能以及手持式數位視訊行動接收裝置(Digital Video broadcasting-Handheld)系統規劃為研究重點。主要分為三個部分：(1)單頻網路系統之架構 (2)DVB-T歐規數位電視地面廣播行動接收場強量測 (3)DVB-H手持式數位視訊行動接收裝置系統規格性能介紹。 進行全島數位電視發射站臺電波涵蓋範圍之行動接收電場強度及性能量測，以瞭解數位電視訊號傳輸狀況，經由實測證明使用分集式(Diversity Reception)接收技術之數位接收機可提高行動接收及室內接收之效能，此外，數位電視訊號行動接收順暢的關鍵取決於兩項技術，即分集式接收技術與單頻網路發射站台之建置，單頻網路之應用可提高頻譜使用效率，而使用分集式接收技術，將可改善在高速移動下之行動接收效能。 由歐洲數位視訊廣播發展組織(Digital Video Broadcasting project)，以歐規數位電視地面廣播(Digital Video Broadcasting-Terrestrial；DVB-T)傳輸技術標準為基楚，所提岀之手持式數位視訊行動接收裝置(DVB-H)技術規範，已進行驗證與標準化程序，DVB-H提供手持式數位視訊行動裝置所要求之低功率消耗、高移動性、共通平台與無縫(seamless)網路切換等功能。此外，未來可藉由行動通訊網路、網際網路與DVB-H廣播網路之整合，不論是在移動、行動或是室內皆能藉由單天線接收更多樣化的節目內容與進行互動式服務。本論文將會探討有關時間分割(time-slicing)、多重協定封裝-前向錯誤更正(multi-protocol encapsulation-forward error correction)、網路架構、軟式交換(soft handover)機制與DVB-H手持式數位視訊行動裝置相關應用之技術。
關鍵字
歐規數位電視並列摘要
The Digital TV system can not only provide high quality of video and audio services, it can also be carried other types of data. It will be one of the most important vehicles taking us to the information highway in the 21st century. The terrestrial version of the DVB system was developed during the mid-1990s. The European DVB-T 6MHz digital terrestrial TV standard is adopted for digital TV system in Taiwan. The standard is implemented by COFDM modulate technology which has the functions of building SFN (Single Frequency Network) broadcasting and mobile reception. In this thesis, the focus is put on the mobile reception performance of DVB-T(Digital Video Broadcasting-Terrestrial), and on DVB-H(Digital Video broadcasting-Handheld) planning. There are three main points in this thesis: (1)Single Frequency Network infrastructure; (2)field test of DVB-T system for mobile reception; (3)Introduction of the technology specification of DVB-H. After measuring the field strength of DTV signals in Taiwan.the result is proved that diversity reception technology will improve the performance of mobile and indoor reception. Therefore, it is concluded that the success of mobile reception will be decided by two technologies: the diversity reception and the Single Frequency Network (SFN). The SFN technology makes the spectrum more efficient, and the use of diversity (two-tuner) receiver technology improves high-speed mobile reception of DVB-T, even in difficult situations. In DVB project, the technical specification of DVB-H was developed according to the transmission technology which was defined by the DVB-T standard. The specification now has been under the standardization and validation phases. In addition, the DVB-H provides the functions of low-power consumption, high mobility, common platform and seamless handover between the network. It can also receive multimedia services with single antenna in portable, mobile and indoor environments. Applied in different handheld devices, various contents, such as interactive-services, can be delivered to users through integration between DVB-H and cellular network. In this thesis, I would like to extend some the key technologies, including timing-slicing, MPE-FEC (multi-protocol encapsulation-forward error correction), the network structure, soft handover mechanism, and the applications associated with DVB-H.