  We study synchronization in populations of phase-coupled stochastic
three-state oscillators characterized by a distribution of transition rates. We
present results on an exactly solvable dimer as well as a systematic
characterization of globally connected arrays of N types of oscillators (N=2,
3, 4) by exploring the linear stability of the nonsynchronous fixed point. We
also provide results for globally coupled arrays where the transition rate of
each unit is drawn from a uniform distribution of finite width. Even in the
presence of transition rate disorder, numerical and analytical results point to
a single phase transition to macroscopic synchrony at a critical value of the
coupling strength. Numerical simulations make possible the further
characterization of the synchronized arrays.
