An ASIC supporting external clock synchronization for distributed real-time systems

Designing clock synchronization algorithms for distributed real-time systems based on packet networks requires to decide on the amount and functionality of proper hardware support. Targeting a 1 μs precision and similar accuracy measures in case of external UTC supply from GPS-receivers, this paper describes pertinent features of a peripheral device called UTCSU manufactured as an ASIC. The most salient one is the introduction of an adder-based clock, that allows a fine grained rate adjustment, continuous amortization, and maintenance of local accuracy intervals