Systems and methods for noise canceling

Patent metadata

Field	Value
Publication number	US-2016196817-A1
Application number	US-201414911239-A
Country	US
Kind code	A1
Filing date	Aug 12, 2014
Priority date	Aug 12, 2013
Publication date	Jul 7, 2016
Grant date	—

Abstract

Active Noise Cancellation (ANC) systems and methods that reduce latency to improve performance. In certain embodiments the systems sample a noise signal using a sample period to create a stream of digital signal data that is representative of the noise signal. A data transport layer carries the digital signal data to a signal processor. The transport layer temporally organizes the digital signal data to place the digital signal data within an initial phase of a sample period. The remaining phase of the sample period is set to a duration that allows the signal processor to process the digital signal data carried in the initial phase and to output the processed data during the same sample period. In this way, the processing of data occurs within one sample period and the latency is reduced and predictable.

First claim

1 . A noise cancellation system, comprising
one or more analog to digital converters capable of sampling a noise signal and generating a stream of digital data at a higher rate than a sample period, a digital transport layer coupled to the one or more of the analog to digital converters for organizing the stream of digital data to place the digital data in an initial phase of the sample period, a signal processing filter capable of receiving the digital data carried in the initial phase of the sample period and generating processed signals during the sample period in which the digital data was received, and a digital to analog converter for converting the processed signals to an analog form.

2 . The noise cancellation system of claim 1 , wherein the signal processing filter further comprises
a sequencing processor capable of arranging the processed signals in an output stream to have the digital transport layer carry selected processed signals to the digital to analog converters ahead of other processed signals.

3 . The noise cancellation system of claim 1 , wherein the digital transport layer extends between the analog to digital converters and the digital to analog converters.

4 . The noise cancellation system of claim 1 , wherein the digital transport layer comprises a multi-channel digital audio transportation protocol.

5 . The noise cancellation system of claim 4 , wherein the multi-channel digital audio transportation protocol is selected from one of I2S, A2B, TDM, parallel data, LVDS, SPDIF, SoundWire, BlueTooth, and byte level transport.

6 . The noise cancellation system of claim 1 , wherein the analog to digital converter includes a power control process for powering the analog to digital converter for a period of time that is less than the sample rate.

7 . The noise cancellation system of claim 1 , further comprising a microphone pre-amplifier circuit coupled to the analog to digital converter.

8 . The noise cancellation system of claim 1 , further comprising a speaker amplifier coupled to the digital to analog converter.

9 . The noise cancellation system of claim 1 , wherein the signal processing filter includes more than one digital filter.

10 . The noise cancellation system of claim 1 , wherein the signal processing filter start is skewed to lower the instructions per second (MIPS) required to generate the noise cancellation signals.

11 . The noise cancellation system of claim 1 , wherein the ADC to DAC share a digital transport layer.

12 . The noise cancellation system of claim 1 , wherein the digital transport layer is capable of organizing the digital data in a sample period to have one or more contiguous processing phases to provide a processing phase having a duration set to be less than or equal to a time determined for the signal processor to generate the processed signals.

13 . The noise cancellation system of claim 12 wherein the one or more contiguous processing phases have a duration selected to support more than one noise cancellation system.

14 . The noise cancellation system of claim 13 wherein the more than one contiguous processing sections have a duration selected to allow the generation of noise cancellation signals for noise signals from independent input sources.

15 . The noise cancellation system of claim 13 where the more than one contiguous processing sections have a duration selected to allow the generation of noise cancellation signals generated by independent output sources for cancelling noise from one input source.

16 . A method for noise cancellation, comprising
oversampling an analog noise signal above a sample period to generate a stream of digital data, providing a digital transport layer for organizing the stream of digital data to place the digital data in an initial phase of the sample period, carrying the digital data to a signal processing filter capable of receiving the digital data carried in the initial phase of the sample period and generating processed signals during the sample period in which the digital data was received, and converting the processed signals to an analog form.

17 . The method of claim 16 , further comprising
sequencing the processed signals in an output stream to have the digital transport layer carry selected processed signals to the digital to analog converters ahead of other processed signals.

18 . The method of claim 16 , further comprising
powering the analog to digital converters for a period of time that is less than the sample rate.

19 . The method of claim 16 , further comprising
organizing the digital data in a sample period to have one or more contiguous processing phases to provide a processing phase having a duration set to be less than or equal to a time determined for the signal processor to generate the processed signals.

20 . The method of claim 19 , wherein the one or more contiguous processing phases have a duration selected to support more than one noise cancellation system.

Assignees

• Analog Devices Inc

Inventors

• Mortensen Mikael
• Nolet Melissa
• Nguyen Khiem Quang

Classifications

• G10K2210/1282

  Automobiles · CPC title

• G10K2210/3053

  Speeding up computation or convergence, or decreasing the computational load · CPC title

• H03M1/001

  Analogue/digital/analogue conversion · CPC title

• G10K11/178 Primary

  by electro-acoustically regenerating the original acoustic waves in anti-phase · CPC title

• G10K11/17823

  Reference signals, e.g. ambient acoustic environment · CPC title