Coupled Phase-locked Loops: Stability, Synchronization, Chaos And Communication With ChaosModern technological, biological, and socioeconomic systems are extremely complex. The study of such systems largely relies on the concepts of competition and cooperation (synchronization). The main approaches to the study of nonlinear dynamics of complex systems are now associated with models of collective dynamics of networks and ensembles, formed by interacting dynamical elements. Unfortunately, the applicability of analytical and qualitative