Redundant clock synthesizer

Abstract

A clock architecture employing redundant clock synthesizers is disclosed. In one embodiment, a computer system includes first and second clock boards. The first clock board may act as a master, generating a system clock signal, while the second clock board acts as a slave. The first clock board may monitor a phase difference between a first crystal clock signal and a feedback clock signal. If the phase difference exceeds a limit, the first crystal clock signal may be inhibited, preventing the first clock board from generating the system clock signal. The second clock board may monitor the system clock board in reference to a feedback clock signal. If the second clock board detects a predetermined number of consecutive missing clock edges, it may enable a second crystal clock signal, which may be used to generate a system clock signal.