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Active noise cancellation (ANC) system with selectable sample rates

A technology of active noise cancellation and noise cancellation, applied in active noise control, sounding equipment, instruments, etc., can solve the problems of reducing ANC performance and long anti-noise delay

Pending Publication Date: 2020-10-20
CIRRUS LOGIC INT SEMICON
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Long anti-noise delay reduces ANC performance

Method used

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  • Active noise cancellation (ANC) system with selectable sample rates
  • Active noise cancellation (ANC) system with selectable sample rates
  • Active noise cancellation (ANC) system with selectable sample rates

Examples

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Embodiment Construction

[0011] Embodiments of an ANC system with selectable sampling rates for filter processing are described. Before and after the filter of the ANC system are respectively a decimator with selectable decimation rate and an interpolator with selectable interpolation rate. A selectable decimation rate decimator and selectable interpolation rate interpolator operate to provide a selectable sampling rate for the filter. Processing by the filter at a lower sampling rate can advantageously reduce power consumption in portable devices including ANC systems. However, a lower sampling rate may introduce additional latency in the ANC system. In one embodiment, for example, the decimation rate and interpolation rate may be statically selected based on the type of portable audio device employing the ANC system. For example, in one product, a manufacturer may prioritize lower power consumption over higher noise cancellation, in which case a higher decimation and interpolation rate could be st...

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Abstract

An active noise cancellation (ANC) system including a selectable decimation rate decimator that receives an oversampled digital input and has an input that selects the decimation rate, a filter that receives an output of the decimator, and a selectable interpolation rate interpolator that receives an output of the filter and has an input that selects the interpolation rate. The selectable decimation rate decimator and the selectable interpolation rate interpolator operate to provide a selectable sample rate for the filter based on the selected decimation and interpolation rates. The filter maybe an anti-noise filter, feedback filter, and / or a filter that models an acoustic transfer function of the ANC system. Rate selection may be static, or dynamically controlled based on battery or ambient noise level. A ratio of the decimation rate and the interpolation rate is fixed independent of the dynamically controlled decimation and interpolation rates.

Description

[0001] Cross References to Related Applications [0002] This application claims priority based on U.S. Provisional Application Serial No. 62624984, entitled "ANC SYSTEM WITH CONFIGURABLE SAMPLE RATES," filed on February 1, 2018, said U.S. Provisional Application Incorporated herein by reference in its entirety. Background technique [0003] Portable audio devices such as wireless telephones (eg, mobile / cellular phones, cordless phones) and other consumer audio devices (eg, mp3 players) are widely used. Performance in terms of low power consumption is expected from portable audio equipment. Performance in terms of clarity is also expected from such a device. Intelligibility can be improved by providing noise cancellation, such as active noise cancellation (ANC), using a microphone to measure the ambient acoustic event, and then using signal processing to insert an anti-noise signal into the output of the device to cancel the ambient acoustic event. The ANC system has strict...

Claims

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Application Information

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IPC IPC(8): G10K11/16
CPCG10K2210/3051G10K11/17823G10K11/17853G10K11/17855G10K2210/108G10K11/17854G10K11/17815G10K2210/3026G10K2210/3027G10K2210/3028
Inventor 加布里埃尔·沃格尔杰弗里·艾德森瑞安·A·海尔曼尼廷·克瓦特拉
Owner CIRRUS LOGIC INT SEMICON