- 學位論文
同軸電纜乙太傳輸誤碼率降低的探討
The Research of The Bit Error Rate Reduction at Ethernet Over Coax
摘要
網路的迅速發展，數位產業已經深入日常生活中，越來越多的設備與產品都 必需透過網路來傳遞資訊。乙太網路（Ethernet, IEEE 802.3）是現今最普遍的 區域網路（Local Area Network, LAN）架構，早期使用粗纜（RG-11 / 10Base5） 可以傳輸達500 公尺的距離，細纜（RG-58 / 10Base2）可以傳輸185 公尺的距 離，但是都只能以10Mb 的速度使用半雙工的方式傳輸，而不能同時間傳送與接 收資料。改善後的10/100BaseT 網路拓樸為星狀結構，每一條網路都是獨立的線 路，傳送與接收分別使用2 組雙絞線，所以能以全雙工的模式來傳輸資料，但是 每一區段的傳輸距離則被限制在100 公尺以內。 本文則是使用75Ω的RG-6 同軸電纜（Coaxial Cable），在100Mb 的速率下 使用全雙工傳輸，且能達到100 公尺以上的傳送距離，經過實驗證明，本文所使 用的電路架構，甚至能達到200 公尺以上的傳輸距離，位元誤碼率（BER）也低 於10−10。使用特性阻抗為75Ω的同軸電纜，與有線電視(CATV)系統的特性阻抗 相同，所以本文的電路架構與有線電視訊號結合後，將使得同軸電纜能同時傳輸 乙太網路信號與有線電視訊號。 如何透過同軸電纜做長距離的數位資訊傳輸，SNR、Insertion Loss、Return Loss、Cable Loss…等等，有哪些因素會影響位元誤碼率與傳輸距離，將是本文 探討的重點。
並列摘要
The rapid developments of the network and digit-based industries penetrated into daily life have made more equipments and products transmit the information by network. Ethernet（IEEE 802.3）is nowadays the most popular Local Area Network (LAN) protocol. In the early period the thick cable (RG-11/10Base5) was allowed to transmit 500 meters in distances, and thin cable (RG-58/10Base2) was allowed to transmit 185 meters in distances. However both cables can only use the half-duplex for the speed of 10Mb, but both cables cannot simultaneously transmit and the receive data at the same time. After the improvement 10/100BaseT network uses the star topology; each network uses the independent line; the transmission and the receiving of data separately use a pair of twisted lines and can therefore both function at the full duplex; however the transmitting range at each sector is limited to 100 meters. By using 75 Ω RG-6 coaxial cable operating at the speed of 100 Mb with the full duplex mode in this article, the transmission distance can reach over 100 meters and it has been proved after experiments. The electric circuit structures used in this article even can achieve transmitting range over 200 meters, and Bit Error Rate (BER) is also lower than10−10 . By using the coaxial cables with 75Ω impedance which is the same as system impedance of CATV, the electric circuit integrated with the cable TV signal will enable the coaxial cable simultaneously to transmit Ethernet signal and the cable TV signal. How to make the digit information transmission in the long distance by using the coaxial cable, SNR, Insertion Loss, Return Loss, Cable Loss.., and which factors will affect BER and the transmitting range will be a key research in this article.