Institute of Phonetic Sciences, University of Amsterdam, Proceedings 22 (1998), 61-83
Jan van Dijk
Abstract
The purpose of this work is to determine filter characteristics for an arbitrary point of the basilar membrane. We will do this in a phenomenological way. Firstly, attention is paid to the equation of motion for the basilar membrane. It appears that the pressure in this equation has to fulfil a special boundary condition. This condition has the shape of a homogeneous mixed type boundary condition for the pressure in the surrounding fluid. We consider this condition as an equation at the real axis of the complex plane. In consequence of this, the solution can be given in an explicit way. Secondly, both the filter characteristics for an arbitrary point of the membrane and the corresponding impulse response are determined. The impulse response is a chirp-like signal. This corresponds to recent physiological observations. We changed the slopes in the amplitude characteristic of the filter. The result is that small variations of these slopes lead to responses which resemble the observed responses.