  We consider a Kuramoto model for the dynamics of an excitable system
consisting of two coupled active rotators. Depending on both the coupling
strength and the noise, the two rotators can be in a synchronized or
desynchronized state. The synchronized state of the system is most stable for
intermediate noise intensity in the sense that the coupling strength required
to desynchronize the system is maximal at this noise level. We evaluate the
phase boundary between synchronized and desynchronized states through numerical
and analytical calculations.
