有線電視網路分頻交換系統之研究

Abstract

本論文研究雙向有線電視網路系統中,使用分頻交換系統的可能性,在 此我們選擇分頻交換系統而不採用分時交換系統,原因在於前者較有彈性, 不受訊號形式的影響,以及可用在不同的通道傳輸速度之下,因為分頻交換 系統祇是在源端與末端之間建立一條通道,所以僅需決定好通訊協定而不 須涉及詳細的通訊形式,此外,它還有與傳輸速度,調變解調方式無關等好 處,為選擇適用於分頻交換系統的交換機,我們探討了不同結構的交換以及 它們的特性,且為了提高網路的可靠度,我們提出了DNTN的網路架構,並探 討分頻交換在個人無線通訊的可行性 The possibility of using FDM switching in the bi-directional CATV networks was investigated. Under the FDM based CATV infrastructure, FDM switching hasseveral advantages over TDM switching. As the FDM switching just establishesa communication path between the source and destination, it only requires anend- to-end MAC protocal without involving in the details of mutual communica-tions. Thus the FDM switching system can provide a flexible communication environment in the CATV network. Moreover, it is bit rate, modulation and format independent, and has smooth growth capability. In order to offer a suitable switch used in the FDM switching system, different switching structures, their crosspoints, signal strength and cross-talk were studied. To increase the efficiency of a switch,the idea of dynamic port assignment (DPA) is discussed. We further propose a dualnetwork twin node (DNTN) topology to build a reliable network and discuss the application of FDM switching in personal communication systems.