  The objective of this paper is to explore the possibility to couple two van
der Pol (vdP) oscillators via a resistance-capacitance (RC) network comprising
a Ag-TiOx-Al memristive device. The coupling was mediated by connecting the
gate terminals of two programmable unijunction transistors (PUTs) through the
network. In the high resistance state (HRS) the memresistance was in the order
of MOhm leading to two independent selfsustained oscillators characterized by
the different frequencies f1 and f2 and no phase relation between the
oscillations. After a few cycles and in dependency of the mediated pulse
amplitude the memristive device switched to the low resistance state (LRS) and
a frequency adaptation and phase locking was observed. The experimental results
are underlined by theoretically considering a system of two coupled vdP
equations. The presented neuromorphic circuitry conveys two essentials
principle of interacting neuronal ensembles: synchronization and memory. The
experiment may path the way to larger neuromorphic networks in which the
coupling parameters can vary in time and strength and are realized by
memristive devices.
