Computing the Pull - in Range of Phase Locked Loop Using Particle Swarm Optimization

The pull-in process is a mechanism where phaselocked loop acquires lock state. It is known as the highest range of frequency where the phase locked loop (PLL) has a separatrix cycle. No exact formula exists for calculating this frequency. Many numerical methods have been proposed for computing this cycle when the loop pulls in. In this paper, the well-known particle swarm optimization (PSO) method is proposed to compute the separatrix cycle and the value of the pull-in frequency. The method is applied to a second order phase locked loop and results obtained is compared with Runge–Kutta method. Simulations results show the robustness and efficacy of the proposed method.