
time between the pairs, T
s
, is not related to the monitored signal bit rate, and can be
many orders of magnitude slower. Plotting the pairs produces information-rich pat-
terns called phase portraits, which are of similar complexity to eye diagrams, but do
not require clock recovery. A fundamental difference between the two techniques is
that the phase portrait contains information about the probability distributions of
closely spaced samples, or equivalently, distributions of waveform slopes. This
information is absent in eye diagrams, which are constructed from samples separated
by large periods. For a one-bit delay, Dt = T, the technique geomet ...