System for estimating sound pressure levels at the tympanic membrane using pressure-minima based distance

• US 20100260343A1
• Filed: 08/07/2009
• Published: 10/14/2010
• Est. Priority Date: 08/08/2008
• Status: Active Grant

• Current Assignee: Starkey Laboratories Incorporated
• Original Assignee: Starkey Laboratories Incorporated
• Inventors: Recker, Karrie LaRae, Zhang, Tao, Lin, Wei Li
• Granted Patent: US 8,571,224 B2
• Time in Patent Office: Days
• US Class Current: 381/58
• CPC Class Codes: A61B 5/121 evaluating hearing capacity

Abstract

In various embodiments, a system is used to provide an apparatus configured to measure sound in an ear canal of a wearer'"'"'s ear at a distance from a tympanic membrane of the ear. The sound is measured and received by the apparatus to produce a signal. A frequency analysis is performed on the signal to determine output as a function of the frequency and to determine the frequency of the minima (null). Further, a distance equal to a quarter wavelength of the null frequency is calculated. A correction factor associated with the quarter wavelength is retrieved and applied to the output to generate a corrected output. An estimated sound pressure level at the tympanic membrane from the corrected output is produced.

Claims

1. A method, comprising:

providing an apparatus configured to measure sound in an ear canal of a wearer'"'"'s ear at a distance from a tympanic membrane of the ear;

measuring sound received by the apparatus to produce a signal;

performing frequency analysis on the signal to determine output as a function of the frequency;

determining a null frequency of a minima of the output;

calculating a distance equal to a quarter wavelength of the null frequency;

retrieving a correction factor associated with the quarter wavelength;

applying the correction factor to the output to generate a corrected output; and

producing an estimated sound pressure level at the tympanic membrane from the corrected output.

2. The method of claim 1, wherein performing the frequency analysis includes performing a fast Fourier transform (FFT) on the signal;

3. The method of claim 1, wherein the correction factor is a function of width of the minima.

4. The method of claim 1, wherein the correction factor is a function of depth of the minima.

5. The method of claim 1, further comprising generating a complex tone for sound measurement by the apparatus.

6. The method of claim 5, wherein generating a complex tone for sound measurement includes:

generating a complex test tone with frequencies separated by 50 Hz.

7. The method of claim 5, wherein generating a complex test tone for sound measurement includes:

generating a complex test tone with frequencies at or above 100 Hz and at or below 16000 Hz.

8. The method of claim 1, further comprising generating a swept tone for sound measurement by the apparatus.

9. The method of claim 1, further comprising:

outputting the estimated sound pressure level at the tympanic membrane from the corrected output on a display device.

10. An apparatus for measuring sound pressure level of sound in an ear canal at a tympanic membrane, comprising:

an audio output device to play the sound;

a microphone configured to receive the sound in the ear canal at a first distance from the tympanic membrane and to provide a signal based on the received sound; and

a processor executing instructions configured to;

perform frequency analysis on the signal and determine output as a function of frequency;

determine a null frequency of a minima of the output;

calculate a second distance equal to a quarter wavelength of a wave at the null frequency;

retrieve a correction factor associated with the second distance, and

apply the correction factor to the output to generate a corrected output related to an estimated sound pressure level at the tympanic membrane.

11. The apparatus of claim 10, wherein the processor is programmed to perform an FFT on the signal.

12. The apparatus of claim 10, wherein the correction factor is a function of width of the minima.

13. The apparatus of claim 10, wherein the correction factor is a function of depth of the minima.

14. The apparatus of claim 10, wherein the sound is a complex tone.

15. The apparatus of claim 14, wherein the complex is a complex tone with frequencies at or above 100 Hz and at or below 16000 Hz.

16. The apparatus of claim 14, wherein the complex is a complex tone with frequencies separated by 50 Hz.

17. The apparatus of claim 10, wherein the sound is a swept tone.

18. The apparatus of claim 10, further comprising a display device to present the estimated sound pressure level at the tympanic membrane from the corrected output.

19. The apparatus of claim 10, further comprising a probe, wherein the probe is attached to the audio output device.

20. The apparatus of claim 10, wherein the processor is configured to send the sound wirelessly to the audio output device.