Eye diagram simulation in full-wave simulator

I am studying eye-diagram while questions raised up in my mind.

To my best understanding, eye-diagram superimpose outputs based on bit period (or Unit Interval). This assumes that a random 0-1 series is set as the input signal, and its output is squeezed into one bit period, right?

With that said, I have two questions:

1. For freq-domain solvers, how is eye-diagram being calculated?

2. What I am more concerned is: For all transient simulators, the initial period is not a steady state. (E.g. devices need to be charged and biased), thus the early outputs are actually not reflecting the system's steady performance. Shall eye-diagram include these initial responses? Or it is only valid for steady-state systems?

I can help out with 2! Never really used a freq-domain solver.

Eye-diagrams are only generated using steady state information for the reasons you mentioned. Eye-diagrams can help measure jitter, over/undershoot, and other distortions of the steady state signal, so including the early outputs when everything is charging up will only interfere and obscure the useful information in the eye diagram!

Thanks Jsherman, that is very clear explanation.

There are actually two types of eye diagrams: the usual digital eye diagram and there is also a I-Q eye diagram. It sounds like your looking for the digital eye diagram. ADS has some nice tools for this. I'd be interested to hear what other tools can do this.

Thanks DonnyP, I pretty much learned all about digital eye diagram, can you introduce a bit more about I-Q diagram?
Also, one my original question remains unanswered

1. For freq-domain solvers, how is eye-diagram being calculated?

Any inputs?