In view of time-varying and instability of crystal oscillators in phase lock loops due to the effects of temperature

a scheme of implicit self-tuning control combined with forward compensation is proposed on the basis of the recursive identification algorithm

i.e.implicit self-tuning control algorithm.This scheme designs the controller regulating system in accordance with the parameters obtained from the identification so as to minimize the output signal variance variations.Application of this algorithm in the self-tuning prediction modules and simulation and validation of this algorithm by using MATLAB show that application of this algorithm can not only optimize the system identification parameters

but also considerably stabilize the output signals

satisfying the requirement of the output signals in phase lock loops to track the input signals.