  To implement reliable quantum information processing, quantum gates have to
be protected together with the qubits from decoherence. Here we demonstrate
experimentally on nitrogen-vacancy system that by using continuous wave
dynamical decoupling method, not only the coherence time is prolonged by about
20 times, but also the quantum gates is protected for the duration of
controlling time. This protocol shares the merits of retaining the superiority
of prolonging the coherence time and at the same time easily combining with
quantum logic tasks. It is expected to be useful in task where duration of
quantum controlling exceeds far beyond the dephasing time.
