Synchronization of two memristive coupled van der Pol oscillators

TL;DR

This paper demonstrates how two van der Pol oscillators can be synchronized through a memristive RC network, highlighting potential for neuromorphic systems with adaptable coupling.

Contribution

It introduces a memristive coupling mechanism for van der Pol oscillators, enabling frequency adaptation and phase locking, advancing neuromorphic circuit design.

Findings

Memristive device switches from high to low resistance state, enabling synchronization.

Coupled oscillators exhibit phase locking after memristive switching.

Experimental results align with theoretical coupled van der Pol equations.

Abstract

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.