US Patent 7656196 Multi-state latches from n-state reversible inverters

N-valued re-circulating latches using n-valued reversible inverters with n>3 are disclosed. Latches using n-valued self-reversing inverters are provided; latches using n-valued universal inverters are provided; and latches using inverters which are not self-reversing or universal are also provided. A latch may use two individually controlled gates. It may also use one individually controlled gate. N-valued latches are provided wherein a state is represented by a signal being an independent instance of a physical phenomenon. A latch not using absence-of-signal as a state is also provided.