Auditory prosthesis, noise suppression apparatus and feedback suppression apparatus having focused adaptive filtering

For use in an audio system having microphone means for generating an input signal from sounds external to said system and transducer means for emitting sound in response to an output signal provided by signal processing means, wherein a portion of the sound emitted by said transducer means propagates to the microphone means to add a feedback signal to the input signal, a feedback suppression apparatus comprising:

• probe means for generating a noise signal, said noise signal being injected into said output signal;
• combining means operatively coupled to said input signal and to an adaptive filter output signal for subtracting said adaptive filter output signal from said input signal so as to substantially cancel said feedback signal from said input signal and to generate an error signal that is input into said signal processing means;
• first filter means operatively coupled to said error signal for generating a filtered error signal by selectively passing an audio spectrum of said error signal corresponding to said feedback signal's audio spectrum;
• adaptive filter means operatively coupled to said filtered error signal for generating said adaptive filter output signal and for providing said adaptive filter output signal to said combining means;
• and
• second filter means for selectively passing to said adaptive filter means an audio spectrum of said noise signal corresponding to said feedback signal's audio spectrum.

An auditory prosthesis disposed to process acoustical signal energy, comprising:

• a microphone for generating an audio input signal in response to said acoustical signal energy, said input signal having both a desired component and an undesired component;
• first filter means operatively coupled to said input signal for generating a reference signal by selectively passing an audio spectrum of said input signal containing primarily said undesired component;
• adaptive filter means operatively coupled to said input signal and to said reference signal for adaptively filtering said input signal in order to provide an adaptive filter output signal;
• combining means operatively coupled to said input signal and to said adaptive filter output signal for combining said adaptive filter output signal with said input signal to cancel said undesired component from said input signal and produce an error signal;
• second filter means operatively coupled to said error signal for selectively passing to said adaptive filter means an audio spectrum of said error signal corresponding to said undesired component of said input signal;
• said adaptive filter means being controlled in accordance with a signal filter algorithm that employs both said reference signal and a portion of said error signal passed by said second filter means;
• a signal processor having an input coupled to said error signal and producing an desired output signal;
• output transducer means for emitting sound in response to said desired output signal;
• whereby said undesired component is effectively removed from said input signal without substantially affecting said desired component of said input signal.

An auditory prosthesis comprising:

• microphone means for generating an input signal from sounds external to said prosthesis;
• transducer means for emitting sound in response to an output signal, wherein a portion of the sound emitted by said transducer means propagates to the microphone means to add a feedback signal to the input signal;
• signal processing means for producing said output signal;
• probe means for generating a noise signal, said noise signal being injected into said output signal;
• combining means operatively coupled to said input signal and to an adaptive filter output signal for subtracting said adaptive filter output signal from said input signal so as to substantially cancel said feedback signal from said input signal and to generate an error signal that is input into said signal processing means;
• first filter means operatively coupled to said error signal for generating a filtered error signal by selectively passing an audio spectrum of said error signal corresponding to said feedback signal's audio spectrum;
• second filter means for selectively passing an audio spectrum of said noise signal corresponding to said feedback signal's audio spectrum;
• and
• adaptive filter means operatively coupled to said audio spectrum of said noise signal from said second filter means and to said filtered error signal for generating said adaptive filter output signal and for providing said adaptive filter output signal to said combining means.

For use in an audio system having input microphone means for generating an input signal from sounds external to said system and transducer means for emitting sound in response to an output signal provided by signal processing means, wherein a portion of the sound emitted by said transducer means propagates to the input microphone means to add a feedback signal to the input signal, a feedback suppression apparatus comprising:

• reference microphone means responsive to said feedback signal for generating a noise signal, said noise signal being injected into said output signal;
• combining means operatively coupled to said input signal and to an adaptive filter output signal for subtracting said adaptive filter output signal from said input signal so as to substantially cancel said feedback signal from said input signal and to generate an error signal that is input into said signal processing means;
• first filter means operatively coupled to said error signal for generating a filtered error signal by selectively passing an audio spectrum of said error signal corresponding to said feedback signal's audio spectrum;
• second filter means for selectively passing an audio spectrum of said noise signal corresponding to said feedback signal's audio spectrum;
• and
• adaptive filter means operatively coupled to said audio spectrum of said noise signal and to said filtered error signal for generating said adaptive filter output signal and for providing said adaptive filter output signal to said combining means.