| The uncertainty in the gain of some voltage controlled oscillators (VCOs) in analog phase-locked loops (PLLs) suggests some form of adaptive tuning or adaptive control to assure proper performance. In this dissertation, a modified version of the classical model reference adaptive control (MRAC) methodology is suggested for first order PLLs. Subsequently, the output of the adaptive PLL (APLL) is proven to converge to that of an intermediate model, whose output "follows" that of the desired model in some sense. In addition, global parameter convergence results are obtained, regardless of lock, for the "white" noise input normally present in radio receivers. Averaging analysis is used to derive an implementation technique for the APLL which has nice robustness properties in the face of unmodeled dynamics, plant (VCO) noise, and measurement noise, and future directions of research are suggested. |
