Method for Reducing Jitter in Multi-Gigahertz ATE

Controlling jitter on a picosecond (or smaller) time scale has become one of the most difficult challenges for testing multi-gigahertz systems. In this paper we present a novel method for reducing jitter in timing-critical ATE signals. This method uses a real-time averaging approach to combine multiple ATE signals and produces timing references with significantly lower random jitter. For example, we demonstrate a 3times reduction in jitter by combining eight ATE signals (each with sigma=4ps) to produce a low-jitter signal (sigma=1.3ps). The measured jitter reduction is shown to closely match that predicted by theory. This counter-intuitive (but welcome) result is of general interest for the design of any low-jitter system, and is particularly helpful for multi-GHz ATE where precise timing is so critical