Eye pattern margin measurement and receiver stress detection device

A system and method are provided wherein binary communications signals are received, and sequences of values of like types of these, such as positive ones, positive zeroes, negative ones, and negative zeroes, are observed. Responsive to a sequence of like-type signals, a reference potential is driven generally in the direction of value of these signals, and most responsively in the direction of the greatest signal degradation. A reference potential for each type is then stored, and the one of these having the most degraded amplitude is selected, and an indication of the percentile of its degradation is provided.