9.5. Peak Distortion Analysis

Peak distortion analysis is commonly used to extract a worst-case eye diagram ^{[15] [16] [17] [18] [19]}. This section first describes peak distortion analysis techniques based on single-bit response and multiple-edge response methods. Typical peak distortion analysis is done at the data sampling phase. Therefore it only gives worst-case voltage margin. This section extends peak distortion analysis to multiple phases to generate worst-case eye that has not only the worst-case voltage margin but also the worst-case timing margin. At the end, numerical examples are presented to compare the worst-case eye margin extracted using different methods.

9.5.1. Single-Bit Response (SBR) Method

Given an SBR, the largest undershoot can be found by picking the data sequence that results in the most negative total ISIs, as follows. Beginning with the symbol-spaced single-bit response p_Δt at phase Δt, let be the main cursor, and be a vector that contains all the ISI terms of the single-bit response at phase Δt. The lowest possible undershoot is given by , where denotes the l₁-norm, the sum of the absolute values of the elements.