> Hmm... maybe the assumption that all edges walk around at the same speed is > wrong?
It's really really hard to make things like edges travel at exactly the same speed. If it isn't exact, then one will eventually catch up with another and self destruct. The signal integrity wizards discuss eye patterns for multi gigabit serial links. They now divide jitter into two parts: random and data-dependent. If you have a long string of 0s as compared to a single 0 between 1s, the data line will have a chance to get closer to a solid low. Starting from closer to 0 takes slightly longer to make a transition. You can see it in the eye diagram. Does anybody have a scope on a ring oscillator? Is the signal symmetric? If not, that says that the H-L transition travels at a different speed than the L-H transition. Actually, just looking at the prop times on a gate mignt be good enough. The ring is just a handy signal generator. It would be fun to make a ring with no inverters, inject a pulse, and watch to see how long it lasts. I'll bet there is matastability type math that depends on the width of the pulse. If you get the width exactly right it will last a long time. Too long and it settles to all 1s. Too short and it settles to all 0s. -- These are my opinions. I hate spam. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
