- 學位論文
時間同步協定之研究與應用
Characterizations of Time Synchronization Protocols and Their Applications
摘要
時間同步在許多領域中扮演著極重要的角色，如定位導航、電力系統、高速通信網路等。隨著科技的進步，對於時間同步的精準度要求也隨之升高。而精密時間同步協定(Precision Time synchronization Protocol; PTP)是第一個達到次微秒精準度的協定。本論文先介紹時間同步協定與時間量測等相關知識，再說明PTP之重點。於瞭解PTP後，順利地找到了一些直接的應用。例如在次微秒的範圍內，時間間隔測量器(Time Interval Counter; TIC)為專門測量時頻訊號的專業儀器，其價格甚為昂貴。本研究發現，PTP以軟體或硬體實現之後，可以取代TIC。經由網路平台所實現的建置於PTP之時頻量測系統，具有極高的經濟價值。 為改善PTP的時間同步效能，本文提出以灰色比例積分(Gray Proportional Integral)控制器和門閥比例積分(Threshold Proportional Integral)控制器來改善同步暫態時間過久的問題，亦由於PTP的時間同步效能可達次微秒等級，本文以時間戳記來當作加、解密的參數，可讓密碼隨時間每秒更新。這種時變密碼系統(Time Varying Encryption System; TVES)之破解甚為困難，因而強化了保密的效果，而讓資訊之傳送更為安全。
並列摘要
Time synchronization protocols play an important role in numerous applications, such as instrumentation, power systems and high-speed communications. With the rapid advances in technology, the demands placed on the accuracy of time synchronization have increased. The precision time synchronization protocol (PTP) was the first protocol developed to successfully synchronize distributed devices in the sub-microsecond (10-6 seconds) range. This dissertation firstly introduces the background knowledge regarding time synchronization protocols as well as the measurement of time and frequency. Then the ideas of PTP are investigated. New applications of PTP are proposed then. For example, PTP can be used as the case of the time measurement system to replace the Time Interval Counter (TIC). The benefits of PTP based time frequency measurement include low cost and high efficiency. The Gray Proportional Integral (GPI) controller and the Threshold Proportional Integral (TPI) controller are proposed to reduce the transient time interval during the time synchronization processes. Since PTP can provide time synchronization precision in the sub-microsecond (10-6 seconds) level, the time stamps are used as the encryption parameters. The pass words are revised every second. Such hind of Time Varying Encryption System (TVES) is quite safe since it is difficult to be cracked.