Rational Clocking

Communication between independently-clocked digital subsystems typically involves a nite probability of synchronization failure whose minimization introduces delays and consequent performance costs. This paper explores a technique that eliminates both the inherent unreliability of such communication and the performance overhead it implies. Our approach maintains a known phase relationship between clocks whose frequencies are related by a rational factor, and exploits the predictability of their relative phases to algorithmi-cally time communications without run-time arbitration contests.