Phase Locked Loop based on adaptive observer

A phase Locked Loop is a control system that generates an alternating signal with a bounded phase respect to an input signal, a feedback loop makes a comparison between these two signals and modifies its output signal frequency. This paper presents a PLL scheme which is aimed to estimate the angular frequency of the input voltage as well as a low pass filter function for cleaning this distorted signal. A prototype based on operational amplifiers has been built and simulations and experimental results are presented to prove its performance