Patent ID: 6999546

Claim:
A system for phase aligning a first timing signal with a second timing signal, the system comprising: a selection unit coupled to a plurality of timing sources, wherein one timing source is being used as a reference to produce the first timing signal and at least one timing source is an internal timing source; a detection unit coupled to the selection unit for detecting a failure in the reference timing source of the first timing signal and causing the selection unit to switch to a second timing source to continue generating the first timing signal; a unit coupled to the selection unit for comparing the phase of the first timing signal after switching to the second timing source to the phase of the second timing signal, wherein the unit introduces gradual phase alterations to the second timing signal until the first and second timing signals are in-phase, and wherein the unit provides a feedback signal that is in phase with the first timing signal before failure of the reference timing source and is reset, prior to the first and second timing signals being in-phase, to be in phase with the first timing signal from the second timing source after failure of the reference timing source.