= Synchronous pulse detector with two-zero rearming
{title2=$q_1^+=a,\ q_0^+=q_1\lor(q_0\land a),\ z=q_1\land\neg q_0$}
The displayed two-register <Moore machine>, initialized to $q_1q_0=00$, generates a one-clock pulse on a sampled high when ready, then waits for two consecutive sampled zeros before it can generate another. The codes $00,10,11,01$ represent ready, pulse, disabled and one-zero-seen respectively. From ready a high enters pulse; from pulse the next edge leaves for disabled on a high or one-zero-seen on a low. Disabled enters one-zero-seen on a low. A second consecutive low returns to ready, whereas a high returns to disabled. This transition analysis proves the output rule, the one-period duration and the immediate first-edge response after reset. It assumes a synchronous input meeting setup and hold requirements.
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