Granted Patent B2

US 8,199,919 · App. 11/928,621 · Granted Jun 12, 2012

Abstract

Claims (32)

1. A method of operating an audio device configured to be inserted in an ear canal, the method comprising:

measuring first sound pressure levels (SPL ECR ) of an electrical drive signal directed to an ear canal receiver (ECR) of the audio device during a time period Δt having a plurality of samples;

simultaneously measuring second sound pressure levels (SPL ECM ) for acoustic energy received by an ear canal microphone (ECM) of the audio device during the time period Δt;

calculating a sound pressure level (SPL) dose (SPL_Dose Δt ) during the time period Δt using the second sound pressure levels (SPL ECM ) of the ECM;

combining the SPL dose (SPL Dose Δt ) with an SPL dose of a previous time period to form a total SPL dose (SPL Dose total ); and

modifying the electrical drive signal based on the first sound pressure levels (SPL ECR ) of the electrical drive signal and the total SPL dose, such that a value of the total SPL dose is maintained proximate to a SPL dose threshold over time.

2. The method according to claim 1 further comprising:

calculating a remaining duration time (Time — 100%) for continuing operation of the ECR based on the second sound pressure levels (SPL ECM ).

3. The method according to claim 1 , further comprising:

comparing the total SPL dose to a threshold value and reading an action parameter from a readable memory when the total SPL dose is greater than the threshold value.

4. The method according to claim 3 further comprising:

performing an action associated with the action parameter, where the action includes at least one of modifying an operation of the audio device, modifying the electrical drive signal directed to the ECR, and sending a notification signal to a user.

5. The method according to claim 4 , where modifying the operation of the audio device includes at least one of the following:

setting a time after which the audio device shuts down;

increasing a noise reduction ratio (NRR) of the audio device; and

activating active noise cancellation of non-ECR generated acoustic energy.

6. The method according to claim 4 , where modifying the electrical drive signal directed to the ECR includes at least one of the following:

reducing a signal to noise ratio by reducing a magnitude of the electrical drive signal sent to the ECR;

chopping the electrical drive signal at a rate unnoticeable by the user, where the chopping reduces a total sound pressure level of an acoustic signal generated by the ECR; and

reducing frequencies in a spectral signature of the electrical drive signal and converting the result into a modified acoustic signal.

7. The method according to claim 4 , where sending the notification signal to the user includes at least one of the following:

sending an acoustic voice notification;

sending an acoustic non-voice notification;

activating at least one indicator light; and

activating a vibratory warning system.

8. The method according to claim 2 where the time period Δt is an n-th time period, and

where the SPL dose (SPL_Dose Δt ) is calculated using:

SPL Dose Δt =(Δ t /Time — 100%), where Time — 100% has the form:

Time — 100% (n)=T c /(2^((SPL ECM −PSL)/ER)), where PSL is a permissible sound level, Tc is a critical time period and ER is an exchange rate.

9. The method according to claim 8 , where the total SPL dose (SPL_Dose total ) is calculated by:

SPL_Dose total =SPL Dose( n− 1)+SPL_Dose Δt ,

where SPL_Dose(n−1) is the total SPL Dose of the previous time period.

Assignments (11)