The "modern digital" model of gates having inputs and outputs is in fact a simplified case. It's unlikely that a digital logic student today would ever have been exposed to gate elements that can work bidirectionally (I'm not talking about tri-state, I'm talking about logic elements that have no preferred input vs output). In general, even symmetrical ring oscillator circuits using elements that do not have a preferred direction, will settle down into rotating one way or the other depending on infinitesimal details of initial conditions. See in particular the neon-light ring oscillator here: http://donklipstein.com/sillyne2.html
This is an example of "symmetry breaking", a term I learned in quantum electrodynamics class!, and the reason particles have mass! I don't actually understand the Higgs Boson but I do understand that neon light ring oscillator because I built it long before I took QED :-). Tim N3QE On Wed, Mar 18, 2015 at 4:28 AM, Hal Murray <hmur...@megapathdsl.net> wrote: > > > While for (optical/electrical) delay line oscillators, the way to go is > to > > add a frequency selective element, this is not done for ring oscillators. > > > So, how do people keep ring oscillators from oscillating at higher modes? > > I think the answer is that you don't have to do anything. It takes care of > it by itself. > > Suppose you have a long string of buffers and 1 inverter in a ring. > Suppose > you start out with 3 transitions. That's the normal 1 transition with an > extra pulse. The key idea is that the edges don't propagate at exactly the > same speed. So one edge will catch up with another and they will self > destruct. > > It would be fun to set that up and watch it on a scope. You could do that > with 3 NAND gates. Feed a reset signal into the other side of all 3 gates. > (watch the wire lengths) Maybe in a FPGA. > > > -- > These are my opinions. I hate spam. > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.