Circuit and method for adaptation of hearing device microphones
AssigneeSiemens Audiologische Technik GmbH
InventorsGeorg-Erwin Arndt, Joachim Eggers, Thomas Hanses, Torsten Niederdränk, Hartmut Ritter, Gunter Sauer
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Abstract
The microphones used in hearing devices normally possess different characteristic lines that are to be adapted to one another. For this purpose, the amplitude of an output signal of a first microphone and the amplitude of an output signal of a second microphone are measured. The output signal of the first microphone is subsequently filtered dependent on both measured amplitudes, such that the difference between the two output signals is reduced. One of the two microphones hereby serves as a reference, and an absolute normalization can be foregone.
Claims8
A method for reciprocal adaptation of a plurality of microphones of a hearing device, comprising the steps of:
- receiving incoming audio signals respectively with a plurality of microphones, with each microphone generating an output signal dependent on the audio signals received by that microphone, said microphones having respectively different sensitivities such that a difference exists between a first output signal from a first of said plurality of microphones and a second output signal from a second of said plurality of microphones;
- measuring a first amplitude of said first output signal in a predetermined frequency range;
- measuring a second amplitude of said second output signal in said predetermined frequency range;
- and
- reducing said difference by filtering said first output signal dependent on said first amplitude and on said second amplitude in a filter by multiplying filtering said first output signal with a transfer function of said filter having a numerator polynomial and a denominator polynomial, and in a feedback regulation loop containing said filter, varying only said numerator polynomial in said feedback regulation loop to equalize said first and second amplitudes.
A hearing device comprising
- a plurality of microphones that receive incoming audio signals, each microphone generating an output signal dependent on the audio signals received by that microphone, said microphones having respectively different sensitivities such that a difference exists between a first output signal from a first of said plurality of microphones and a second output signal from a second of said plurality of microphones;
- a first measurement unit that measures a first amplitude of said first output signal in a predetermined frequency range;
- a second measurement unit that measures a second amplitude of said second output signal in said predetermined frequency range;
- and
- a filter and a feedback regulation loon containing said filter that reduce
- said difference by filtering said first output signal dependent on said first amplitude and on said second amplitude by multiplying said first output signal with a transfer function of said filter having a numerator polynomial and a denominator polynomial and, in said feedback regulation loop, varying only said numerator polynomial.
Dependencies are inferred from the claim text.