Circuitry for establishing a traveling wave on a rotary traveling wave oscillator is described. The circuitry includes a gain portion that establishes a wave in a preferred direction by degenerating any wave traveling opposite to the preferred direction and regenerating any wave traveling in the preferred direction. If there are two such gain portions, each having opposite preferred directions, then a wave that is presently established in one direction can be degenerated and a new wave can be established in the opposite direction, thereby achieving reversibility of the traveling wave in real time. Each of the gain portions included in a plurality of regeneration/degeneration elements present on the rotary oscillator. Each of the regeneration/degeneration elements is connected to a pair of taps on the oscillator, the taps being separated by a direction dependent phase difference.