1. A type of cyclotron that modulates the frequency of the electric fields that accelerate the particles, thereby keeping the accelerating forces synchronized with the particle as its mass increases with velocity due to the effects of relativity, and providing greater energies for the accelerated particles than an unsynchronized cyclotron.
2. A type of cyclotron that synchronizes its accelerating voltage with particle velocity in order to compensate for the relativistic mass increase of the particle as it approaches the speed of light.