Sliding bias and peak limiting for optical hearing devices
AssigneeEarlens Corporation
InventorsDaniel J. Freed, Sunil Puria
Life of this patent
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Abstract
A processor comprises instructions to adjust a bias of an input signal in order to decrease a duty cycle of a pulse modulated optical signal. The bias can be increased, decreased, or maintained in response to one or more measured values of the signal. In many embodiments, a gain of the signal is adjusted with the bias in order to inhibit distortion. The bias can be adjusted slowly in order to inhibit audible noise, and the gain can be adjusted faster than the bias in order to inhibit clipping of the signal. In many embodiments, one or more of the bias or the gain is adjusted in response to a value of the signal traversing a threshold amount. The value may comprise a trough of the signal traversing the threshold.
Claims45
A hearing apparatus to transmit an audio signal to an ear of a user with light, comprising:
- an input to receive the audio signal;
- a light source to generate an optical signal;
- an output transducer to receive the optical signal from the light source;
- and
- a processor coupled to the input, the processor configured with instructions to receive the audio signal,
- determine a bias of the audio signal and a biased audio signal in response to the audio signal, and
- output the biased audio signal to circuitry to drive the light source with the biased signal in order to decrease light energy of the optical signal transmitted from the light source,
- wherein the processor comprises instructions for a look ahead delay to decrease the gain to inhibit clipping in response to a negative signal below a threshold amount detected with the look ahead delay.
A hearing apparatus to transmit an audio signal to an ear of a user with light, comprising:
- an input to receive the audio signal;
- a light source to generate an optical signal;
- an output transducer to receive the optical signal from the light source;
- and
- a processor coupled to the input, the processor configured with instructions to receive the audio signal,
- determine a bias of the audio signal and a biased audio signal in response to the audio signal, and
- output the biased audio signal to circuitry to drive the light source with the biased signal in order to decrease light energy of the optical signal transmitted from the light source,
- wherein the processor comprises instructions to limit the bias in response to a noise floor associated with one or more of delta sigma modulation circuitry, the circuitry to drive the light source, the light source or the output transducer to receive the output signal.
A hearing apparatus to transmit an audio signal to an ear of a user with light, comprising:
- an input to receive the audio signal;
- a light source to generate an optical signal;
- an output transducer to receive the optical signal from the light source;
- and
- a processor coupled to the input, the processor configured with instructions to receive the audio signal,
- determine a bias of the audio signal and a biased audio signal in response to the audio signal, and
- output the biased audio signal to circuitry to drive the light source with the biased signal in order to decrease light energy of the optical signal transmitted from the light source,
- wherein the audio signal comprises a fixed bias and the processor comprises instructions to determine the biased audio signal in response to the fixed bias of the audio signal.
Dependencies are inferred from the claim text.