  Self-sustaining nonlinear oscillators of practically any type can function as
latches and registers if Boolean logic states are represented physically as the
phase of oscillatory signals. Combinational operations on such phase-encoded
logic signals can be implemented using arithmetic negation and addition
followed by amplitude limiting. With these, general-purpose Boolean computation
using a wide variety of natural and engineered oscillators becomes potentially
possible. Such phase-encoded logic shows promise for energy efficient
computing. It also has inherent noise immunity advantages over traditional
level-based logic.
