Headset noise exposure dosimeter

• US 20030191609A1
• Filed: 02/01/2002
• Published: 10/09/2003
• Est. Priority Date: 02/01/2002
• Status: Active Grant

• Current Assignee: Plantronics, Inc. (HP Inc.)
• Original Assignee: Plantronics, Inc. (HP Inc.)
• Inventors: Ewer, Paul A., Bernardi, Robert J.
• Granted Patent: US 6,826,515 B2
• Time in Patent Office: Days
• US Class Current: 702/191
• CPC Class Codes: G01H 3/14 Measuring mean amplitude; Measuring mean power; Measuring time integral of power
• CPC Class Codes: H04R 1/1091 Details not provided for in groups H04R1/1008 - H04R1/1083
• CPC Class Codes: H04R 2430/01 Aspects of volume control, not necessarily automatic, in sound systems

Abstract

A method and apparatus for monitoring and controlling exposure to noise related to a headset are described. The method includes sampling an input sound signal to produce samples of the input sound signal, calculating from these samples a headset sound level corresponding to the input sound signal, calculating cumulative exposure of a headset user to the headset sound level at a specific point in time, and calculating a gain adjustment for the input sound signal to ensure that the total sound to which the headset user will be exposed during a selected time period is within the regulatory maximum level. Advantageously, the method and apparatus of the present invention allow accurate real-time monitoring of cumulative exposure to headset noise and real-time adjustment of headset gain to ensure compliance with regulatory maximum sound exposure levels.

Claims

1. A method for monitoring noise exposure from a headset comprising:

sampling an input sound signal to produce a plurality of samples as a function of time;

calculating from said plurality of samples a headset sound level corresponding to the input sound signal;

calculating real-time exposure of a user of the headset to the headset sound level; and

extrapolating the real-time exposure to the end of a preselected time period.

2. The method of claim 1, wherein sampling an input sound signal comprises sampling at selected frequency bands.

3. The method of claim 1, wherein sampling an input sound signal comprises sampling at selected sampling rates.

4. The method of claim 1, wherein the input sound signal is from a public switched telephone network.

5. The method of claim 1, further comprising:

digitizing the input sound signal at sampled frequencies.

6. The method of claim 1, wherein calculating the headset sound level comprises using a transfer function that includes a headset speaker frequency response factor, a headset electrical sensitivity factor, and a free field equivalency factor.

7. The method of claim 1, wherein calculating real-time exposure to the headset sound level comprises using a weighting function that includes a trading relationship between exposure time and exposure level.

8. The method of claim 7, wherein a trading relationship is selected between approximately 3 dB to approximately 6 dB for doubling exposure time.

9. The method of claim 1, wherein extrapolating the real-time exposure to the end of a preselected time period comprises calculating a rate of exposure change.

10. The method of claim 1, further comprising:

determining real-time levels of impulse noise and continuous noise.

11. A method for controlling noise exposure from a headset comprising:

sampling an input sound signal to produce a plurality of samples as a function of time;

calculating from said plurality of samples a headset sound level corresponding to the input sound signal;

calculating real-time exposure of a user of the headset to the headset sound level;

extrapolating the real-time exposure to the end of a preselected time period;

calculating a gain adjustment for the input sound signal; and

adjusting gain of the input sound signal in conformity with the gain adjustment calculation.

12. The method of claim 11, wherein calculating a gain adjustment for the input sound signal comprises:

comparing extrapolated exposure to regulatory threshold levels.

13. The method of claim 11, wherein calculating a gain adjustment for the input sound signal comprises determining a time frame for gain adjustment depending upon the magnitude of the gain adjustment.

14. The method of claim 11, wherein adjusting gain of the input sound signal is carried out immediately for a small gain adjustment and is carried out over a longer time frame for a large gain adjustment.

15. The method of claim 14, wherein a small gain adjustment is in the range of approximately 1 dB to approximately 2 dB.

16. The method of claim 14, wherein a large gain adjustment is in the range of approximately 3 dB to approximately 6 dB.

17. The method of claim 11, further comprising:

selecting calculation parameters comprising regulatory threshold levels, time periods, headset apparatus type, and user gain adjustment levels.

18. The method of claim 11, further comprising:

visually displaying sound measurement values comprising impulse noise, continuous noise, exposure levels, and gain adjustments.

19. A headset audio dosimeter, comprising:

sampling circuitry for sampling an input sound signal to produce samples of said input sound signal;

a headset sound level technique for calculating from said samples of said input sound signal a headset sound level corresponding to the input sound signal;

an exposure technique for calculating from said headset sound level the cumulative exposure of a user of a headset to the headset sound level;

an exposure extrapolation technique for extrapolating the expected cumulative exposure of the user to the headset sound level to the end of a preselected time period; and

a gain adjustment technique for calculating a gain adjustment for the input sound signal to limit the total cumulative exposure of the user to sound over the preselected time period to below a selected value.

20. The headset audio dosimeter of claim 19, wherein the sampling circuitry is capable of sampling the input sound signal at selected frequency bands and at selected sampling rates.

21. The headset audio dosimeter of claim 19, wherein the input sound signal is from a public switched telephone network.

22. The headset audio dosimeter of claim 19, wherein the headset sound level technique comprises a transfer function that includes a headset speaker frequency response factor, a headset electrical sensitivity factor, and a free field equivalency factor.

23. The headset audio dosimeter of claim 19, wherein the exposure technique comprises a weighting function that includes a trading relationship between exposure time and exposure level.

24. The headset audio dosimeter of claim 19, further comprising:

a user interface for allowing a user to select a trading relationship of between approximately 3 dB to approximately 6 dB for doubling exposure time.

25. The headset audio dosimeter of claim 19, wherein the exposure extrapolation technique comprises:

structure for calculating a rate of exposure change.

26. The headset audio dosimeter of claim 19, wherein the gain adjustment technique comprises:

structure for comparing between extrapolated exposure and regulatory threshold levels.

27. The headset audio dosimeter of claim 19, wherein the gain adjustment technique comprises:

structure for determining a time frame for gain adjustment depending upon the magnitude of the gain adjustment.

28. The headset audio dosimeter of claim 27, wherein the structure is capable of adjusting gain immediately for a small adjustment and over a longer time for a large gain adjustment.

29. The headset audio dosimeter of claim 28, wherein a small adjustment is in the range of approximately 1 dB to approximately 2 dB.

30. The headset audio dosimeter of claim 28, wherein a large adjustment is in the range of approximately 3 dB to approximately 6 dB.

31. The headset audio dosimeter of claim 19, further comprising:

a user interface for allowing a user to select calculation parameters comprising regulatory threshold levels, weighting factors, time periods, headset apparatus type, and user gain adjustment levels.

32. The headset audio dosimeter of claim 19, further comprising:

a technique for determining levels of impulse noise and continuous noise.

33. The headset audio dosimeter of claim 19, further comprising:

a display to visually show sound measurement values comprising impulse noise, continuous noise, exposure levels, and gain adjustments.

34. A headset audio dosimeter system, comprising:

a sound signal source for producing an input sound signal;

means for sampling the input sound signal to produce samples of said input sound signal;

means for storing said samples;

a processor;

a program stored in a memory for allowing said processor to calculate from said samples a gain adjustment for the input sound signal;

gain control circuitry responsive to said calculated gain adjustment for adjusting gain of the input sound signal in conformity with the calculated gain adjustment to produce an adjusted sound signal; and

a headset apparatus to receive the adjusted sound signal.

35. The headset audio dosimeter system of claim 34, wherein said program comprises instructions to cause said processor to:

calculate a headset sound level corresponding to the input sound signal from said samples of said input sound signal;

calculate from the headset sound level the cumulative exposure of a user of a headset to the headset sound level;

extrapolate the expected cumulative exposure of the user to the headset sound level to the end of a preselected time period; and

calculate a gain adjustment for the input sound signal to limit the total cumulative exposure to sound of the user over the preselected time period to below a selected value.

36. The headset audio dosimeter system of claim 34, wherein the sound signal source comprises a public switched telephone network.

37. The headset audio dosimeter system of claim 34, wherein the sampling means samples the input sound signal at selected frequency bands and at selected sampling rates.

38. The headset audio dosimeter system of claim 35, wherein the program further comprises instructions to cause said processor to:

calculate a headset sound level using a transfer function that includes a headset speaker frequency response factor, a headset electrical sensitivity factor, and a free field equivalency factor.

39. The headset audio dosimeter system of claim 35, wherein the program further comprises instructions to cause said processor to:

calculate exposure to the headset sound level using a weighting function that includes a trading relationship between exposure time and exposure level.

40. The headset audio dosimeter system of claim 34, further comprising:

a user interface for allowing a user to select a trading relationship of between approximately 3 dB to approximately 6 dB for doubling exposure time.

41. The headset audio dosimeter system of claim 35, wherein the program further comprises instructions to cause said processor to:

extrapolate exposure to the end of a preselected time period at a calculated rate of exposure change; and

calculate a gain adjustment for the input sound signal by comparing extrapolated exposure to regulatory threshold levels.

42. The headset audio dosimeter system of claim 35, wherein the program further comprises instructions to cause said processor to:

determine a time frame for gain adjustment for the input signal depending upon the magnitude of gain adjustment.

43. The headset audio dosimeter system of claim 42, wherein structure is capable of adjusting gain immediately for a small adjustment and over a longer time for a large adjustment.

44. The headset audio dosimeter system of claim 43, wherein a small adjustment is in the range of approximately 1 dB to approximately 2 dB.

45. The headset audio dosimeter system of claim 43, wherein a large adjustment is in the range of approximately 3 dB to approximately 6 dB.

46. The headset audio dosimeter system of claim 34, further comprising:

a headset adapter which operably connects a variety of headset apparatus to the gain adjust circuitry.

47. The headset audio dosimeter system of claim 46, wherein the headset adapter includes a user interface for allowing gain adjustment by the user.

48. The headset audio dosimeter system of claim 34, further comprising:

a user interface for allowing a user to select calculation parameters comprising regulatory threshold levels, weighting factors, time periods, headset apparatus type, and user gain adjustment levels.

49. The headset audio dosimeter system of claim 34, wherein the program further comprises instructions to cause said processor to:

determine levels of impulse noise and continuous noise.

50. The headset audio dosimeter system of claim 34, further comprising:

a display to visually show sound measurement values calculated by the program comprising impulse noise, continuous noise, exposure levels, and gain adjustments.