| 摘要 |
<p>Noise reduction circuitry in a hearing aid includes a programmable filter (41) coupled to a microphone (31) coupled to the ear canal. The filter is programmed in a feedback loop in which the coefficients of the filter are set in accordance with a signal from the microphone. The filter is programmed for a transfer function that is substantially the inverse of the spectrum of the sound detected by the microphone to provide a relatively quiet chamber in the ear canal.</p> |
