yeah, if memory serves, the 2:1 coupling is how the parametron mentioned in the article works; given a reference frequency signal such as 6 gigahertz and some oscillators that can oscillate around 3 gigahertz, you have two possible frequency-locked phases that can serve as 1 and 0. one of the half-frequency oscillators serves as a phase reference for the 1 level and everything else is measured relative to it

hmm, now i see that the article explains this, but i guess i'll leave this here as a simplified summary in case that it's useful to somebody