US Patent 11784619 Disciplining crystals to synchronize timing of independent nodes

A circuit includes a first system-on-chip (SoC) driven by a first clock generator and a second SoC driven by a second clock generator where the first clock generator and the second clock generator have independent time bases. The first and second clock generators are synchronized using an RLC circuit external to the first clock generator and the second clock generator that converts an output of the first clock generator into current pulses and injects the current pulses into the second clock generator to pull an output of the second clock generator into synchronization with the output of the first clock generator. The RLC circuit converts a voltage output of the first clock generator into current pulses at the resonant frequency or specific harmonics of the output of the first clock generator. The second clock generator may include a ring oscillator into which the current pulses are injected.