Design of a 2-Dimensional, Pseudo-Voltage-Domain, Silicon Cochlea

A 2-dimensional cochlear model offers several advantages over the usual 1-dimensional implementations. It allows to properly model the different modes of wave propagation through the cochlea. Furthermore, the number of filters per octave can be increased without increasing the delay along the cochlea, which is not possible with a 1dimensional model. Another practical advantage of the 2-D implementation is that a defect in one of the filters does not disable all filters with a lower characteristic frequency. We have designed an analogue VLSI implementation of a 2-D cochlear model that uses a grid of transistors to model the cochlear fluid mass. The operation of this grid is linear in the pseudo-voltage domain. We present in this paper a pseudo-voltage domain resonator compatible with the resistive grid. Simulations of the resonator and the full implementation of the 2-D cochlea are presented.