The Jitter-Noise Duality and Anatomy of an Eye Diagram
Vladimir Dmitriev-Zdorov, Martin T. Miller, Teledyne LeCroy, Chuck Ferry · 2014
We compare two approaches where the structure of the eye diagram is considered either as a timing uncertainty or alternatively a vertical uncertainty. We show that only the second view allows accurate BER evaluation when the eye is seriously impaired. It follows from BER definition that its proper evaluation should bedelay lock loop based on considering the two portions of the eye diagram, and by their separate integration. With such understanding of BER, it turns out that the jitter-induced vertical noise can be considered same way as the signal’s ISI, although correlated with the latter. We propose a method of statistical simulation based on this view, where the effect of Tx jitter and ISI is considered together. We use the probability mass functions (PMF) to represent both ISI and jitter contributions, which makes the algorithm simple and physically clear. Some interesting effects can be explained based on the proposed approach, for example jitter increase with growing PRBS order of the input pattern.