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 pass-band 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