Non-linear behaviour of charge-pump phase-locked loops

[摘要] The analysis of the mixed analogue and digital structure of charge-pumpphase-locked loops (CP-PLL) is a challenge in modelling and simulation. Inmost cases the system is designed and characterized using its continuouslinear model or its discrete linear model neglecting its non-linear switchingbehaviour. I.e., the time-varying model is approximated by a time-invariantrepresentation using its average dynamics. Depending on what kind of phasedetector is used, the scopes of validity of these approximations aredifferent. Here, a preeminent characterization and simulation technique basedon the systems event-driven feature is presented, merging the logical andanalogue inherent characteristics of the system. In particular, thehigh-grade non-linear locking process and the dead-zone are analyzed.

[学科分类] 电子、光学、磁材料