  We propose and demonstrate a quantum control scheme for hybrid quantum
registers that can reduce the operation time, and therefore the effects of
relaxation, compared to existing implementations. It combines resonant
excitation pulses with periods of free precession under the internal
Hamiltonian of the qubit system. We use this scheme to implement quantum gates
like controlled-NOT operations on electronic and nuclear spins of the
nitrogen-vacancy center in diamond. As a specific application, we transfer
population between electronic and nuclear spin qubits and use it to measure the
Rabi oscillations of a nuclear spin in a system with multiple coupled spins.
