All DPLLs based on fuzzy PI control algorithm

An all DPLL(All-Digital Phase Locked Loop) based on fuzzy PI control algorithm is proposed in this paper. On analyzing system performance of a second-order PI control based PLL(Phase Locked Loop), the relationship between noise bandwidth with PI control parameters is derived, and fuzzy controller of the system is designed. Under the Matlab/Simulink environment, system-level PLL is directly modeled by using DSP Builder®, and then is represented by using VHDL. Software simulation confirms the correctness of the design. The PLL can automatically adjust noise bandwidth according its working state, and it is characteristic of its fast lock speed, small phase jitter, outstanding anti-interference performance and prone to integration and so on.