  Implementing precise operations on quantum systems is one of the biggest
challenges for building quantum devices in a noisy environment. Dynamical
decoupling (DD) attenuates the destructive effect of the environmental noise,
but so far it has been used primarily in the context of quantum memories. Here,
we present a general scheme for combining DD with quantum logical gate
operations and demonstrate its performance on the example of an electron spin
qubit of a single nitrogen-vacancy center in diamond. We achieve process
fidelities >98% for gate times that are 2 orders of magnitude longer than the
unprotected dephasing time $T_{2}$.
