| With the fast development of network technology, network clock synchronization technique becomes more and more widely implemented in areas like distributed control systems, industrial Ethernet and transformer substation. At the same time, the demand on higher accuracy of network clock synchronization is growing quickly toμs level in many cases. To fulfill this growing demand, this thesis provides in-depth research on implementation of high accuracy network clock synchronization system.Through synthesizing a large number of domestic and foreign papers, the thesis analyzes the high accuracy network clock synchronization system and finds the key point of successful high accuracy implementation is reducing or eliminating the oscillation caused by OS and protocol stack, transmission delay fluctuation caused by network components, and influences from instability and resolution of the clock.After analyzing the characteristics of NTP and IEEE1588, the thesis compares the two protocols, points out the advantages of IEEE1588 in improving the accuracy of network clock synchronization and chooses it to be the implementation protocol. Then the four factors that influence accuracy of network clock synchronization: OS and protocol stack, network components, instability and resolution of the clock are studied. The causes and effect, as well corresponding methods of improving accuracy of synchronization are provided. At last, theory of local clock and clock adjustment algorithms are studied, then a local clock component based on ABC is designed and simulated to prove feasibility.The thesis emphasizes research on theory of the four factors that influence accuracy of network clock synchronization, especially the compensation of influences from instability and resolution of the clock, and provides the scheme of state and rate tunable local clock based on ABC. The thesis provides firm ground on hardware design and implementation of high accuracy network clock synchronization system. |
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