Applications of solid-state memristors in tunable filters

In this paper we present a practical approach to employ solid-state TiO₂ memristors as tunable loads in filter configurations. First, memristive devices are employed in discrete realizations of tunable active filter topologies. Using an external programming circuit to set the devices to a desired memristive state enables control of the filter´s characteristics, namely passband boundaries and quality factor. Utilization of a memristor as a tunable load in low-pass and band-pass filter topologies is then experimentally demonstrated. We further expand this concept by demonstrating an amplitude-controlled gain amplifier topology. In this topology, instead of using external control circuitry to set the memristive state, the state is set internally during operation, providing an automatic gain control.