 Synchronous pulse detector with two-zero rearming

The displayed two-register Moore machine, initialized to $q_1{q}_0=00$, 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.