Abstract
Influence of interference in synchronous systems is investigated. It shows new insight into interference phenomena in synchronous systems. According to the analysis, it is possible that the small perturbation to an oscillator is enhanced by positive feedback through the coupling with the other oscillatory system. It means that the inherent phase error caused by thermal noise can lead to large amount of jitter by interference even if there is no external noise. It also reveals the relationship between the occurrence of jitter and the frequency difference in plesiochronous system.