An analog VLSI implementation of the inner hair cell and auditory nerve using a dual AGC model.

An analog inner hair cell and auditory nerve circuit using a dual AGC model has been implemented using 0.35 micron mixed-signal technology. A fully-differential current-mode architecture is used and the ability to correct channel mismatch is evaluated with matched layouts as well as with digital current tuning. The Meddis test paradigm is used to examine the analog implementation's auditory processing capabilities and investigate the circuit's ability to correct DC mismatch. The correction techniques used demonstrate the analog inner hair cell and auditory nerve circuit's potential use in low-power, multiple-sensor analog biomimetic systems with highly reproducible signal processing blocks on a single massively parallel integrated circuit.

A hydromechanical biomimetic cochlea: experiments and models.

The construction, measurement, and modeling of an artificial cochlea (ACochlea) are presented in this paper. An artificial basilar membrane (ABM) was made by depositing discrete Cu beams on a piezomembrane substrate. Rather than two fluid channels, as in the mammalian cochlea, a single fluid channel was implemented on one side of the ABM, facilitating the use of a laser to detect the ABM vibration on the other side. Measurements were performed on both the ABM and the ACochlea. The measurement results on the ABM show that the longitudinal coupling on the ABM is very strong. Reduced longitudinal coupling was achieved by cutting the membrane between adjacent beams using a laser. The measured results from the ACochlea with a laser-cut ABM demonstrate cochlear-like features, including traveling waves, sharp high-frequency rolloffs, and place-specific frequency selectivity. Companion computational models of the mechanical devices were formulated and implemented using a circuit simulator. Experimental data were compared with simulation results. The simulation results from the computational models of the ABM and the ACochlea are similar to their experimental counterparts.