Programmable multichannel hearing aid with adaptive filter
First Claim
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1. A signal processing circuit for a hearing aid, including:
- a sound pressure level transducing means for sensing an audio signal and generating an electrical signal corresponding to said sensed audio signal, and a broadband signal amplifying means for amplifying said electrical signal to produce an amplified electrical signal;
a broadband detecting means for receiving a control input and for generating a control signal having a control signal level proportional to the level of said control input;
an adaptive high-pass filtering means, having as a first input said amplified electrical signal, and as a second input said control signal, for selectively suppressing a low frequency portion of said amplified electrical signal to generate a selectively modified signal, the frequency bandwidth of said suppressed low frequency portion, relative to the width of the entire frequency spectrum of said amplified electrical signal, increasing with said control signal level;
a plurality of restricted bandwidth filters, each receiving said modified signal and enhancing a selected portion of the frequency bandwidth of said modified signal to generate a selected bandwidth signal as its output, and a summing means for receiving said selected bandwidth signals as inputs, and for generating a combined signal based on the summation of said selected bandwidth signals;
an oscillator means for generating a clocking signal provided to each of said restricted bandwidth filters to determine a control frequency for each restricted bandwidth filter, and means for adjustably controlling said oscillator means to simultaneously adjust said control frequencies; and
a receiver means for generating an audio signal corresponding to said combined signal.
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Abstract
A hearing aid is programmable with dual-tone multiple-frequency signals, received through the hearing aid microphone, to adjust operating coefficients of signal conditioning circuitry in the aid. A DTMF receiver filters and detects DTMF tone pairs into digital words provided to a controller for decoding, some of the digital words representing programming instructions and others representing data. In accordance with the instructions, the controller conveys the data to memory operatively associated with a plurality of control ports to the signal conditioning circuitry, with operating coefficients of the conditioning circuitry determined by the contents of the memory.
158 Citations
21 Claims
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1. A signal processing circuit for a hearing aid, including:
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a sound pressure level transducing means for sensing an audio signal and generating an electrical signal corresponding to said sensed audio signal, and a broadband signal amplifying means for amplifying said electrical signal to produce an amplified electrical signal; a broadband detecting means for receiving a control input and for generating a control signal having a control signal level proportional to the level of said control input; an adaptive high-pass filtering means, having as a first input said amplified electrical signal, and as a second input said control signal, for selectively suppressing a low frequency portion of said amplified electrical signal to generate a selectively modified signal, the frequency bandwidth of said suppressed low frequency portion, relative to the width of the entire frequency spectrum of said amplified electrical signal, increasing with said control signal level; a plurality of restricted bandwidth filters, each receiving said modified signal and enhancing a selected portion of the frequency bandwidth of said modified signal to generate a selected bandwidth signal as its output, and a summing means for receiving said selected bandwidth signals as inputs, and for generating a combined signal based on the summation of said selected bandwidth signals; an oscillator means for generating a clocking signal provided to each of said restricted bandwidth filters to determine a control frequency for each restricted bandwidth filter, and means for adjustably controlling said oscillator means to simultaneously adjust said control frequencies; and a receiver means for generating an audio signal corresponding to said combined signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A signal processing circuit for a hearing aid, including:
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a sound pressure level transducing means for sensing an audio signal and generating an electrical signal corresponding to said sensed audio signal, and a broadband signal amplifying means for amplifying said electrical signal to produce an amplified electrical signal; a plurality of restricted bandwidth filters, each receiving said amplified electrical signal and enhancing a selected portion of the frequency bandwidth of said amplified electrical signal to generate a selected bandwidth signal as its output, and a summing means for receiving said selected bandwidth signals as inputs, and for generating a combined signal based on the summation of said selected bandwidth signals; an oscillator means for generating a clocking signal, said clocking signal being provided to each of said restricted bandwidth filters to determine a control frequency for each restricted bandwidth filter, and means for adjustably controlling said oscillator means to simultaneously adjust said control frequencies; a broadband detecting means for receiving a control input and for generating a control signal having a control signal level proportional to the level of said control input; an adaptive high-pass filtering means, having as a first input said combined signal and as a second input said control signal, for selectively suppressing a low frequency portion of said combined signal to generate a selectively modified signal, the frequency bandwidth of said suppressed low frequency portion, relative to the width of the entire frequency spectrum of said combined electrical signal, increasing with said control signal level; and a receiver means for generating an audio signal corresponding to said modified electrical signal. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification