Just want to let everyone know that this circuit doesn't work. I built it today and couldn't get anything at the at the output, not sure what the issue is with this circuit.
research truth tables for XOR, NOR ( in stans fig 6) and XNOR
I think we need XNOR logic to make the signal get through to the 74122
Was that the chip you used when you built the non functional circuit?
I think the patent drawing was drawn wrong on those logic ICs, the only time a NOR gate allows a signal high is when all inputs are LOW and this cant happen with VDD on each of the pins continuously !