Resonant response matching circuit for hearing aid
AssigneeMicro Ear Technology, Inc.
InventorsRandall W. Roberts, David A. Preves, Mark A. Bren
Life of this patent
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Abstract
An apparatus for and method of employing an electronic hearing aid device to assist a hearing impaired patient. The resonance curve of the outer auditory canal of the patient is determined. A device in accordance with the present invention is tuned to a frequency response curve which matches the measured resonance curve. The device is tuned by adjusting the overshoot of a low pass filter stage which is interposed between the microphone input and a class D output stage.
Claims20
An electronic device for use in assisting a hearing impaired patient having a microphone, a preamp, a signal processing stage, and an output amplifier, the electronic device comprising:
- an active low pass filter responsively coupled between said signal processing stage and said output amplifier, said active low pass filter having an adjustable overshoot adapted to tunably match a measured resonance curve to provide a substantially smooth insertion gain frequency response, said active low pass filter including:
- a resistor coupled to a capacitor to form a low pass filter to provide a filtered signal;
- an operational amplifier to receive the filtered signal at an input of the operational amplifier;
- a feedback capacitor coupled from an output of the operational amplifier to the input of the operational amplifier;
- and
- a variable resistor to couple the low pass filter to the input of the operational amplifier, wherein said active low pass filter is adapted to provide a frequency of peak gain of the electronic device.
A hearing aid comprising:
- a microphone;
- a preamp and signal processing stage responsively coupled to said microphone;
- an active low pass filter responsively coupled to said preamp and signal processing stage, said active low pass filter having an adjustable overshoot adapted to tunably match a measured resonance curve to provide a substantially smooth insertion gain frequency response, said active low pass filter including:
- a resistor coupled to a capacitor to form a low pass filter to provide a filtered signal;
- an operational amplifier to receive the filtered signal at an input of the operational amplifier;
- and
- a variable resistor to couple the low pass filter to the input of the operational amplifier such that the variable resistor controls a peak frequency of the low pass filter;
- and
- an output amplifier responsively coupled to said active low pass filter.
A method of assisting a hearing impaired patient comprising:
- tuning a frequency response curve of an electronic hearing aid to a measured resonance curve of said hearing impaired patient such that the electronic hearing aid provides said hearing impaired patient with a smooth insertion frequency response, wherein said tuning includes adjusting a variable resistor coupled to an operational amplifier of an active low pass filter in the electronic hearing aid, the active low pass filter configured having;
- a low pass filter to provide a filtered signal;
- the operational amplifier to receive the filtered signal at an input of the operational amplifier;
- and
- the variable resistor coupling the low pass filter to the input of the operational amplifier such that the variable resistor controls a peak frequency of the low pass filter.
A hearing aid comprising:
- means for converting an acoustic signal into an electrical signal;
- means responsively coupled to said converting means for adjustably processing said electrical signal to produce a desired frequency response, said processing means having an active low pass filter adapted to tunably match a measured resonance curve to provide a substantially smooth insertion gain frequency response, said active low pass filter including:
- a low pass filter to provide a filtered signal;
- an operational amplifier to receive the filtered signal at an input of the operational amplifier;
- and
- a variable resistor to couple the low pass filter to the input of the operational amplifier such that the variable resistor controls frequency of peak gain in a frequency response of the hearing aid;
- and
- means responsively coupled to said processing means for amplifying said processed electrical signal.
Dependencies are inferred from the claim text.