Abstract
This paper presents a new model that describes the physical phenomena
occurring in an individual Outer Hair Cell (OHC) in the human hearing
organ (Cochlea). The new model employs the concept of parametric
amplification and piezoelectricity. As a consequence, the proposed model
may explain in a natural way many as yet unresolved problems about the
mechanisms of: 1) power amplification, 2) non- linearity, 3) fine tuning,
or 4) high sensitivity that take place in the human hearing organ.
Mathematical analysis of the model is performed. The equivalent electrical
circuits of an individual OHC are established. The high selectivity of the
OHC parametric amplifier is analyzed by solving the resulting Mathieu and
Ince differential equations. An analytical formula for the power gain in
the OHC’s parametric amplifier has been developed. The proposed model has
direct physical interpretation and all its elements have their physical
counterparts in the actual structure of the cochlea. The numerical values
of the individual elements of the electrical equivalent circuits are
consistent with the experimental physiological data. It is anticipated
that the proposed new model may contribute in future improvements of human
cochlear implants as well as in development of new digital audio standards.
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