GB2455821B - Split filter - Google Patents

Split filter

Info

Publication number
GB2455821B
GB2455821B GB0810994A GB0810994A GB2455821B GB 2455821 B GB2455821 B GB 2455821B GB 0810994 A GB0810994 A GB 0810994A GB 0810994 A GB0810994 A GB 0810994A GB 2455821 B GB2455821 B GB 2455821B
Authority
GB
United Kingdom
Prior art keywords
split filter
split
filter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
GB0810994A
Other versions
GB2455821A (en
GB0810994D0 (en
Inventor
Khaldoon Al-Naimi
Anthony James Magrath
Alastair Sibbald
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cirrus Logic International UK Ltd
Original Assignee
Wolfson Microelectronics PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wolfson Microelectronics PLC filed Critical Wolfson Microelectronics PLC
Priority to GB0919236A priority Critical patent/GB2465064B/en
Publication of GB0810994D0 publication Critical patent/GB0810994D0/en
Priority to PCT/GB2008/051189 priority patent/WO2009081193A1/en
Publication of GB2455821A publication Critical patent/GB2455821A/en
Application granted granted Critical
Publication of GB2455821B publication Critical patent/GB2455821B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787—General system configurations
    • G10K11/17873—General system configurations using a reference signal without an error signal, e.g. pure feedforward
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1781—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
    • G10K11/17821—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the input signals only
    • G10K11/17823—Reference signals, e.g. ambient acoustic environment
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1781—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
    • G10K11/17821—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the input signals only
    • G10K11/17827—Desired external signals, e.g. pass-through audio such as music or speech
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17853—Methods, e.g. algorithms; Devices of the filter
    • G10K11/17854—Methods, e.g. algorithms; Devices of the filter the filter being an adaptive filter
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787—General system configurations
    • G10K11/17875—General system configurations using an error signal without a reference signal, e.g. pure feedback
    • G10K11/1788—
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787—General system configurations
    • G10K11/17885—General system configurations additionally using a desired external signal, e.g. pass-through audio such as music or speech
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/108—Communication systems, e.g. where useful sound is kept and noise is cancelled
    • G10K2210/1081—Earphones, e.g. for telephones, ear protectors or headsets
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/301—Computational
    • G10K2210/3028—Filtering, e.g. Kalman filters or special analogue or digital filters
GB0810994A 2007-12-21 2008-06-16 Split filter Active GB2455821B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB0919236A GB2465064B (en) 2007-12-21 2008-06-16 Split filter
PCT/GB2008/051189 WO2009081193A1 (en) 2007-12-21 2008-12-15 Noise cancelling system with adaptive high-pass filter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GBGB0725115.0A GB0725115D0 (en) 2007-12-21 2007-12-21 Split filter

Publications (3)

Publication Number Publication Date
GB0810994D0 GB0810994D0 (en) 2008-07-23
GB2455821A GB2455821A (en) 2009-06-24
GB2455821B true GB2455821B (en) 2010-03-17

Family

ID=39048664

Family Applications (3)

Application Number Title Priority Date Filing Date
GBGB0725115.0A Ceased GB0725115D0 (en) 2007-12-21 2007-12-21 Split filter
GB0810994A Active GB2455821B (en) 2007-12-21 2008-06-16 Split filter
GB0919236A Active GB2465064B (en) 2007-12-21 2008-06-16 Split filter

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GBGB0725115.0A Ceased GB0725115D0 (en) 2007-12-21 2007-12-21 Split filter

Family Applications After (1)

Application Number Title Priority Date Filing Date
GB0919236A Active GB2465064B (en) 2007-12-21 2008-06-16 Split filter

Country Status (2)

Country Link
GB (3) GB0725115D0 (en)
WO (1) WO2009081193A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9094744B1 (en) 2012-09-14 2015-07-28 Cirrus Logic, Inc. Close talk detector for noise cancellation
US9107010B2 (en) 2013-02-08 2015-08-11 Cirrus Logic, Inc. Ambient noise root mean square (RMS) detector

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* Cited by examiner, † Cited by third party
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US8737636B2 (en) 2009-07-10 2014-05-27 Qualcomm Incorporated Systems, methods, apparatus, and computer-readable media for adaptive active noise cancellation
US8908877B2 (en) 2010-12-03 2014-12-09 Cirrus Logic, Inc. Ear-coupling detection and adjustment of adaptive response in noise-canceling in personal audio devices
WO2012075343A2 (en) 2010-12-03 2012-06-07 Cirrus Logic, Inc. Oversight control of an adaptive noise canceler in a personal audio device
US8693700B2 (en) * 2011-03-31 2014-04-08 Bose Corporation Adaptive feed-forward noise reduction
US9318094B2 (en) 2011-06-03 2016-04-19 Cirrus Logic, Inc. Adaptive noise canceling architecture for a personal audio device
US9824677B2 (en) 2011-06-03 2017-11-21 Cirrus Logic, Inc. Bandlimiting anti-noise in personal audio devices having adaptive noise cancellation (ANC)
US8958571B2 (en) 2011-06-03 2015-02-17 Cirrus Logic, Inc. MIC covering detection in personal audio devices
US9076431B2 (en) 2011-06-03 2015-07-07 Cirrus Logic, Inc. Filter architecture for an adaptive noise canceler in a personal audio device
US8948407B2 (en) 2011-06-03 2015-02-03 Cirrus Logic, Inc. Bandlimiting anti-noise in personal audio devices having adaptive noise cancellation (ANC)
US9214150B2 (en) 2011-06-03 2015-12-15 Cirrus Logic, Inc. Continuous adaptation of secondary path adaptive response in noise-canceling personal audio devices
US8848936B2 (en) 2011-06-03 2014-09-30 Cirrus Logic, Inc. Speaker damage prevention in adaptive noise-canceling personal audio devices
GB2492983B (en) 2011-07-18 2013-09-18 Incus Lab Ltd Digital noise-cancellation
US9325821B1 (en) 2011-09-30 2016-04-26 Cirrus Logic, Inc. Sidetone management in an adaptive noise canceling (ANC) system including secondary path modeling
US9014387B2 (en) 2012-04-26 2015-04-21 Cirrus Logic, Inc. Coordinated control of adaptive noise cancellation (ANC) among earspeaker channels
US9142205B2 (en) 2012-04-26 2015-09-22 Cirrus Logic, Inc. Leakage-modeling adaptive noise canceling for earspeakers
US9082387B2 (en) 2012-05-10 2015-07-14 Cirrus Logic, Inc. Noise burst adaptation of secondary path adaptive response in noise-canceling personal audio devices
US9123321B2 (en) 2012-05-10 2015-09-01 Cirrus Logic, Inc. Sequenced adaptation of anti-noise generator response and secondary path response in an adaptive noise canceling system
US9319781B2 (en) 2012-05-10 2016-04-19 Cirrus Logic, Inc. Frequency and direction-dependent ambient sound handling in personal audio devices having adaptive noise cancellation (ANC)
US9076427B2 (en) 2012-05-10 2015-07-07 Cirrus Logic, Inc. Error-signal content controlled adaptation of secondary and leakage path models in noise-canceling personal audio devices
US9318090B2 (en) 2012-05-10 2016-04-19 Cirrus Logic, Inc. Downlink tone detection and adaptation of a secondary path response model in an adaptive noise canceling system
US9369798B1 (en) 2013-03-12 2016-06-14 Cirrus Logic, Inc. Internal dynamic range control in an adaptive noise cancellation (ANC) system
US9106989B2 (en) 2013-03-13 2015-08-11 Cirrus Logic, Inc. Adaptive-noise canceling (ANC) effectiveness estimation and correction in a personal audio device
US9215749B2 (en) 2013-03-14 2015-12-15 Cirrus Logic, Inc. Reducing an acoustic intensity vector with adaptive noise cancellation with two error microphones
US9414150B2 (en) 2013-03-14 2016-08-09 Cirrus Logic, Inc. Low-latency multi-driver adaptive noise canceling (ANC) system for a personal audio device
US9208771B2 (en) 2013-03-15 2015-12-08 Cirrus Logic, Inc. Ambient noise-based adaptation of secondary path adaptive response in noise-canceling personal audio devices
US9502020B1 (en) 2013-03-15 2016-11-22 Cirrus Logic, Inc. Robust adaptive noise canceling (ANC) in a personal audio device
US9635480B2 (en) 2013-03-15 2017-04-25 Cirrus Logic, Inc. Speaker impedance monitoring
US9467776B2 (en) 2013-03-15 2016-10-11 Cirrus Logic, Inc. Monitoring of speaker impedance to detect pressure applied between mobile device and ear
US10206032B2 (en) 2013-04-10 2019-02-12 Cirrus Logic, Inc. Systems and methods for multi-mode adaptive noise cancellation for audio headsets
US9066176B2 (en) 2013-04-15 2015-06-23 Cirrus Logic, Inc. Systems and methods for adaptive noise cancellation including dynamic bias of coefficients of an adaptive noise cancellation system
US9462376B2 (en) 2013-04-16 2016-10-04 Cirrus Logic, Inc. Systems and methods for hybrid adaptive noise cancellation
US9478210B2 (en) 2013-04-17 2016-10-25 Cirrus Logic, Inc. Systems and methods for hybrid adaptive noise cancellation
US9460701B2 (en) 2013-04-17 2016-10-04 Cirrus Logic, Inc. Systems and methods for adaptive noise cancellation by biasing anti-noise level
DE102013207161B4 (en) * 2013-04-19 2019-03-21 Sivantos Pte. Ltd. Method for use signal adaptation in binaural hearing aid systems
US9578432B1 (en) 2013-04-24 2017-02-21 Cirrus Logic, Inc. Metric and tool to evaluate secondary path design in adaptive noise cancellation systems
US9264808B2 (en) 2013-06-14 2016-02-16 Cirrus Logic, Inc. Systems and methods for detection and cancellation of narrow-band noise
US9837066B2 (en) 2013-07-28 2017-12-05 Light Speed Aviation, Inc. System and method for adaptive active noise reduction
US9392364B1 (en) 2013-08-15 2016-07-12 Cirrus Logic, Inc. Virtual microphone for adaptive noise cancellation in personal audio devices
US9666176B2 (en) 2013-09-13 2017-05-30 Cirrus Logic, Inc. Systems and methods for adaptive noise cancellation by adaptively shaping internal white noise to train a secondary path
US9620101B1 (en) 2013-10-08 2017-04-11 Cirrus Logic, Inc. Systems and methods for maintaining playback fidelity in an audio system with adaptive noise cancellation
US10219071B2 (en) 2013-12-10 2019-02-26 Cirrus Logic, Inc. Systems and methods for bandlimiting anti-noise in personal audio devices having adaptive noise cancellation
US10382864B2 (en) 2013-12-10 2019-08-13 Cirrus Logic, Inc. Systems and methods for providing adaptive playback equalization in an audio device
US9704472B2 (en) 2013-12-10 2017-07-11 Cirrus Logic, Inc. Systems and methods for sharing secondary path information between audio channels in an adaptive noise cancellation system
US9369557B2 (en) 2014-03-05 2016-06-14 Cirrus Logic, Inc. Frequency-dependent sidetone calibration
US9479860B2 (en) 2014-03-07 2016-10-25 Cirrus Logic, Inc. Systems and methods for enhancing performance of audio transducer based on detection of transducer status
US9648410B1 (en) 2014-03-12 2017-05-09 Cirrus Logic, Inc. Control of audio output of headphone earbuds based on the environment around the headphone earbuds
US9319784B2 (en) 2014-04-14 2016-04-19 Cirrus Logic, Inc. Frequency-shaped noise-based adaptation of secondary path adaptive response in noise-canceling personal audio devices
US9609416B2 (en) 2014-06-09 2017-03-28 Cirrus Logic, Inc. Headphone responsive to optical signaling
US10181315B2 (en) 2014-06-13 2019-01-15 Cirrus Logic, Inc. Systems and methods for selectively enabling and disabling adaptation of an adaptive noise cancellation system
US9478212B1 (en) 2014-09-03 2016-10-25 Cirrus Logic, Inc. Systems and methods for use of adaptive secondary path estimate to control equalization in an audio device
US9552805B2 (en) 2014-12-19 2017-01-24 Cirrus Logic, Inc. Systems and methods for performance and stability control for feedback adaptive noise cancellation
CN108140380B (en) * 2015-08-20 2022-05-27 思睿逻辑国际半导体有限公司 Adaptive noise cancellation feedback controller and method with feedback response provided in part by fixed response filter
KR20180044324A (en) 2015-08-20 2018-05-02 시러스 로직 인터내셔널 세미컨덕터 리미티드 A feedback adaptive noise cancellation (ANC) controller and a method having a feedback response partially provided by a fixed response filter
US9578415B1 (en) 2015-08-21 2017-02-21 Cirrus Logic, Inc. Hybrid adaptive noise cancellation system with filtered error microphone signal
US10013966B2 (en) 2016-03-15 2018-07-03 Cirrus Logic, Inc. Systems and methods for adaptive active noise cancellation for multiple-driver personal audio device
US10810990B2 (en) * 2018-02-01 2020-10-20 Cirrus Logic, Inc. Active noise cancellation (ANC) system with selectable sample rates

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US5105377A (en) * 1990-02-09 1992-04-14 Noise Cancellation Technologies, Inc. Digital virtual earth active cancellation system
EP0505949A1 (en) * 1991-03-25 1992-09-30 Nippon Telegraph And Telephone Corporation Acoustic transfer function simulating method and simulator using the same
US5550923A (en) * 1994-09-02 1996-08-27 Minnesota Mining And Manufacturing Company Directional ear device with adaptive bandwidth and gain control
US5652799A (en) * 1994-06-06 1997-07-29 Noise Cancellation Technologies, Inc. Noise reducing system
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Publication number Priority date Publication date Assignee Title
US5105377A (en) * 1990-02-09 1992-04-14 Noise Cancellation Technologies, Inc. Digital virtual earth active cancellation system
EP0505949A1 (en) * 1991-03-25 1992-09-30 Nippon Telegraph And Telephone Corporation Acoustic transfer function simulating method and simulator using the same
US5652799A (en) * 1994-06-06 1997-07-29 Noise Cancellation Technologies, Inc. Noise reducing system
US5550923A (en) * 1994-09-02 1996-08-27 Minnesota Mining And Manufacturing Company Directional ear device with adaptive bandwidth and gain control
US6078672A (en) * 1997-05-06 2000-06-20 Virginia Tech Intellectual Properties, Inc. Adaptive personal active noise system
US20060251266A1 (en) * 1997-05-06 2006-11-09 Saunders William R Adaptive personal active noise system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9094744B1 (en) 2012-09-14 2015-07-28 Cirrus Logic, Inc. Close talk detector for noise cancellation
US9107010B2 (en) 2013-02-08 2015-08-11 Cirrus Logic, Inc. Ambient noise root mean square (RMS) detector

Also Published As

Publication number Publication date
GB0725115D0 (en) 2008-01-30
WO2009081193A1 (en) 2009-07-02
GB2465064A (en) 2010-05-12
GB2455821A (en) 2009-06-24
GB0919236D0 (en) 2009-12-16
GB2465064B (en) 2010-08-18
GB0810994D0 (en) 2008-07-23

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