“…Although PLL-based circuits are essentially a nonlinear control systems, in modern engineering literature, devoted to the analysis of PLL-based circuits, the main direction is the use of simplified linear models, the methods of linear analysis, empirical rules, and numerical simulation (see a plenary lecture of D. Abramovich at American Control Conference 2002 (Abramovitch, 2002)). While the linearization and analysis of linearized models of control systems may lead to incorrect conclusions 1 , the attempts to justify the reliability of conclusions, based on the application of such simplified approaches, are quite rare (see, e.g., (Suarez and Quere, 2003;Margaris, 2004;Feely, 2007;Banerjee and Sarkar, 2008;Feely et al, 2012;Suarez et al, 2012)). Rigorous nonlinear analysis of PLL-based circuit models is often very difficult task, so for analysis of nonlinear PLL models, numerical simulation is widely used (Troedsson, 2009;Best, 2007;Bouaricha et al, 2012).…”