PLL System with Active PI Filter for FM Demodulation Application

This work develops a phase-locked loop (PLL) system for FM demodulation application. As the dynamic behavior of the PLL system is depends on the loop filter, hence in this paper, the focus is on validating the performance of the FM demodulation using the PLL circuit with an active proportional-integral (PI) filter. The active filter is designed using two methods based on the standard H∞ approach, and the H∞ approach integrated with nonlinear stability criterion. From the experimental results, the performance of the FM demodulation PLL system with the active-PI filter designed using the H∞ approach integrated with nonlinear stability criterion produces smoother output than the one with the filter designed using the H∞ approach.