Frequency-dependent ANR reference sound compression
First Claim
1. An active noise reduction (ANR) circuit comprising:
- a digital feed-forward ANR pathway coupled to a feed-forward microphone, to detect environmental sounds in an environment external to a casing, and coupled to a first acoustic driver to output sounds within the casing; and
a user input;
wherein the digital feed-forward ANR pathway applies a filter using a first set of coefficients to convert signals from the feed-forward microphone to feed-forward anti-noise sounds to reduce environmental sounds within the casing, andin response to activation of the user input, the digital feed-forward ANR pathway applies the filter using a second set of coefficients,the second set of coefficients reducing the degree of feed-forward ANR to enable human speech sounds in the environment external to the casing to be conveyed from the feed-forward microphone to the acoustic driver with less reduction than provided by the first set of coefficients.
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Abstract
An active noise reduction (ANR) circuit includes a digital feed-forward ANR pathway coupled to a feed-forward microphone, to detect environmental sounds in an environment external to a casing, and to a first acoustic driver to output sounds within the casing. The digital feed-forward ANR pathway applies a plurality of filters using a first set of coefficients to convert signals from the feed-forward microphone to feed-forward anti-noise sounds to reduce environmental sounds within the casing. In response to a stimulus, the digital feed-forward ANR pathway applies the plurality of filters using a second set of coefficients, which reduce the degree of feed-forward ANR to enable human speech sounds in the environment external to the casing to be conveyed from the feed-forward microphone to the acoustic driver with less reduction than provided by the first plurality of filters.
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Citations
9 Claims
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1. An active noise reduction (ANR) circuit comprising:
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a digital feed-forward ANR pathway coupled to a feed-forward microphone, to detect environmental sounds in an environment external to a casing, and coupled to a first acoustic driver to output sounds within the casing; and a user input; wherein the digital feed-forward ANR pathway applies a filter using a first set of coefficients to convert signals from the feed-forward microphone to feed-forward anti-noise sounds to reduce environmental sounds within the casing, and in response to activation of the user input, the digital feed-forward ANR pathway applies the filter using a second set of coefficients, the second set of coefficients reducing the degree of feed-forward ANR to enable human speech sounds in the environment external to the casing to be conveyed from the feed-forward microphone to the acoustic driver with less reduction than provided by the first set of coefficients. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification