Experimental verification of synchronization in pulse-coupled oscillators with a refractory period and frequency distribution.

We propose herein globally pulse-coupled electronic-circuit oscillators with a refractory period and frequency distribution. The synchronization of such oscillators, which was analyzed by Konishi and Kokame [Chaos 18, 033132 (2008)], is verified by circuit experiments. Furthermore, we investigate a cluster state in the oscillators and analytically derive a simple condition to estimate the maximum possible number of clusters, which is confirmed by the circuit experiments.