Patent ID: 6047075
Filing Date: 2000-04-04
Classification: H04R

Abstract:
A hearing aid comprising:a. a housing having an interior and an exterior;b. a microphone disposed in the interior of said housing and having at least one sound inlet tube to receive sound from the exterior of said housing;c. an electronic damping circuit for damping electrical signals representative of sound received by said microphone, said electronic damping circuit having a frequency response characterized by a generally flat portion and an inverse peak, said electronic damping circuit comprising at least one switched capacitor filter for defining the inverse peak;d. a damper control circuit connected to provide at least one capacitor bank in said at least one switched capacitor filter, said at least one switched capacitor filter of said electronic damping circuit being responsive to said at least one capacitor bank to vary the filter characteristics of said inverse peak;e. a programming interface for controlling the capacitance of said capacitor bank; andf. an earphone for transducing electrical signals that have been damped by said electronic damping circuit into sound representative of the sound received by said microphone, said earphone having a sound outlet tube for conducting sound to the exterior of said housing, said earphone having a frequency response including a generally flat portion and at least one undamped peak, said at least one undamped peak occurring over a frequency range that is at least partially dependent on the length of said outlet tube, said inverse peak of said electronic damping circuit occurring over a frequency range generally corresponding to the frequency range of said undamped peak thereby to provide a hearing aid output signal that is generally unaffected by undesirable characteristics of said undamped peak.