WO2003003789A2 - Method and apparatus for minimizing latency in digital signal processing systems - Google Patents
Method and apparatus for minimizing latency in digital signal processing systems Download PDFInfo
- Publication number
- WO2003003789A2 WO2003003789A2 PCT/US2002/020223 US0220223W WO03003789A2 WO 2003003789 A2 WO2003003789 A2 WO 2003003789A2 US 0220223 W US0220223 W US 0220223W WO 03003789 A2 WO03003789 A2 WO 03003789A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- input
- signal
- output
- digital
- sampling rate
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
Definitions
- the present invention is generally directed to digital signal processing. More specifically, the present invention is directed to minimization of system latency in signal processing paths including digital control loops.
- the conventional ANC device generally includes a feedback circuit which uses an input transducer such as a microphone to detect ambient noise and an output transducer such as a loudspeaker or receiver to both generate an antinoise signal to cancel the ambient noise and to deliver the desired signal.
- the particular circuit elements vary from implementation to implementation.
- ANC is achieved in analog form by introducing a canceling antinoise signal.
- the actual noise is detected through one or more microphones.
- An antinoise signal of equal amplitude and opposite phase is generated and combined with the actual noise. If done properly, this should result in cancellation of both noises.
- the amount of noise cancellation depends upon the accuracy of the amplitude and phase of the generated antinoise signal.
- ANC can be an effective method of attenuating low- frequency noise which can prove to be very difficult and expensive to control using passive noise control techniques.
- FIG. 1 a block diagram of a first prior art feedback active noise cancellation system 10 as disclosed in U.S. Patents 4,455,675 and 4,644,581 is shown.
- the system 10 has as input a desired signal and a Noise signal and generates an output signal.
- the desired signal is an input voice (Vin) signal and that the output signal is an output voice (Vout) signal.
- the Noise signal is considered to be any disturbance signal in the sound environment other than the desired signal.
- the Vout signal is a combination of the Vin signal, the Noise signal, and an antinoise signal generated by the system 10.
- the antinoise signal exactly cancels the Noise signal leaving only the Vin signal without attenuation as the Vout signal.
- the system 10 attempts to achieve as high a gain as possible in the overall loop within a predetermined frequency range while maintaining the system stability.
- the forward path of the system 10 includes a compressor 12, a compensator 14, a power amplifier 16, and a receiver 18.
- the receiver 18 could be any output transducer including a loudspeaker.
- the feedback path of the system 10 includes a microphone 20 as an input transducer and a microphone preamplifier 22.
- the Vin signal and the feedback path signal are combined in a first summation node 24.
- the forward path signal and the Noise signal are combined in a second summation node 26.
- FIG. 2 a block diagram of a second prior art feedback active noise cancellation system 30 as disclosed in U.S. Patent 5,182,774 is shown.
- the system 30 has similarities with the system 10 of FIG. 1 except that the forward path includes a high-pass filter 32, a low-pass filter 34, and a mid-range filter 36 in combination with the receiver 18. Further, the feedback path adds a high-pass filter 38 to the microphone 20 and the microphone preamplifier 22.
- FIG. 3 a block diagram of a third prior art feedback active noise cancellation system 40 as disclosed in U.S. Patent 5,604,813 is shown.
- a boost circuit 42 has been added outside of the closed loop, that is, before the first summation node 24, to equalize the desired signal.
- the feedback path of the system 40 includes the microphone 20, a plurality of band-pass filters 44, and a low-pass filter 46.
- the conventional analog approach for reducing noise in a system is not without its problems.
- ANC systems are theoretically able to null the noise by generating a phase-inverted antinoise signal, however, as a practical concern, the various components of the system such as the input and output transducers will introduce certain undesirable delays.
- a method and an apparatus for minimizing latency in digital signal processing paths is disclosed.
- One example is an active noise cancellation device.
- the system includes a digital closed feedback loop having a forward path and a feedback path.
- the forward path includes a compensation filter, a digital-to-analog converter, and an output transducer.
- the feedback path includes an input transducer, a feedback delta-sigma modulator, and a feedback sampling-rate converter.
- An input signal is processed in one of several ways into a processed digital input signal having a preselected intermediate sampling rate.
- an analog output signal is processed into a digital feedback signal having substantially the same preselected intermediate sampling rate.
- the processed digital input signal and the digital feedback signal are combined and processed through the forward path to produce an antidisturbance signal that is combined with a disturbance signal to form the analog output signal.
- FIG. 1 is a block diagram of a first prior art feedback active noise cancellation system
- FIG. 2 is a block diagram of a second prior art feedback active noise cancellation system
- FIG. 3 is a block diagram of a third prior art feedback active noise cancellation system
- FIG. 4 is a block diagram of an exemplary embodiment of a feedback active noise cancellation system according to the present invention.
- FIG. 5 is a block diagram of another exemplary embodiment of a feedback active noise cancellation system according to the present invention.
- FIG. 6 is a block diagram of an exemplary embodiment of the input processor of FIGS. 4 and 5 according to the present invention.
- the components, process steps, and/or data structures may be implemented using various types of operating systems, computing platforms, computer programs, and/or general purpose machines.
- devices of a less general purpose nature such as hardwired devices, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), or the like, may also be used without departing from the scope and spirit of the inventive concepts disclosed herein.
- FIG. 4 a block diagram of an exemplary embodiment of a feedback active noise cancellation system 50 according to the present invention is shown.
- the system 50 includes an input processor 52.
- the details of the input processor 52 will be discussed in more detail below.
- the input processor 52 takes an INPUT signal, either analog or digital, and produces a processed digital input signal having an intermediate (I) sampling rate equal to / times Fs where / has a value greater than one and Fs is the sampling rate which is twice the Nyquist rate (Fmax) of the INPUT signal.
- the forward path includes a compensation filter 54, a digital-to-analog converter (DAC) 56, and an output transducer 58.
- DAC digital-to-analog converter
- the forward path is an analog forward path signal.
- the feedback path includes an input transducer 60, a feedback delta-sigma modulator 62, and a feedback sampling-rate converter 64.
- the output of the feedback delta-sigma modulator 62 has a sampling rate equal to N times Fs where N is greater than one. N is also greater than I.
- IFs is the desired sampling rate
- the output NFs needs to be down-sampled to the lower rate by the feedback sampling-rate converter 64.
- the result is a digital feedback signal that has the same sampling rate as the processed digital input signal.
- the intermediate sampling rate is chosen to produce an acceptably low delay in the feedback path. The tradeoff is increased circuit complexity and cost.
- the digital feedback signal is subtracted from the processed digital input signal at a first summation node 66. It is also possible to combine the feedback delta-sigma modulator 62 and the feedback sampling- rate converter 64 into a feedback analog-to-digital converter (ADC) with an output rate of IFs.
- ADC analog-to-digital converter
- the analog forward path signal is combined with an analog DISTURBANCE signal in a second summation node 68.
- the output of the second summation node 68 is the input of the feedback path and the output of the system 50 and is an analog acoustic output signal (Yout).
- FIG. 5 a block diagram of another exemplary embodiment of a feedback active noise cancellation system 70 according to the present invention is shown.
- the system 70 is essentially the same as the system 50 of FIG. 4 except that the compensation filter 54 has been moved from the forward path to the feedback path as shown.
- a whole array of block diagram manipulations are possible and well known to those of ordinary skill in the art. Any embodiment that can be the result of such manipulations is considered to be within the scope of the present invention as exemplified in FIGS. 4 and 5. Further such embodiments will not be presented in detail for the sake of brevity.
- FIG. 6 a block diagram of an exemplary embodiment of the input processor 52 of FIGS. 4 and 5 according to the present invention is shown.
- the input processor 52 takes an INPUT signal, either analog or digital, and produces the processed digital input signal having the intermediate sampling rate (IFs).
- the elements of the input processor 52 will depend in part on the characteristics of the INPUT signal. Various combinations of elements will be outlined below as examples, but other combinations may be possible depending on design choice and circumstances.
- the example elements shown assume that the INPUT signal is an analog signal (Xin).
- the elements of the input processor may include an input delta-sigma modulator 72, a first input sampling-rate converter 74, an equalizer 76, and a second input sampling-rate converter 78.
- the output of the input delta-sigma modulator 72 has a sampling rate equal to M times Fs where M is greater than one and greater than I. This output is then down-sampled by the first sampling-rate converter 74 to a rate equal to K times Fs. K is greater than or equal to one and less than /. Consequently, the output of the first sampling-rate converter 74 must later be up-sampled by the second input sampling-rate converter 78 to the intermediate sampling rate (IFs). Similar to above, it is also possible to combine the input delta-sigma modulator 72 and the first input sampling- rate converter 74 into an input ADC with an output rate of KFs. It is worth noting that M, N, and K are not necessarily related to one another except that K is assumed to be less than M.
- M may or may not be equal to N.
- the equalizer 76 is not in the critical delay path, that is, it is outside of the closed loop. As a result, either Finite Impulse Response (FIR) or Infinite Impulse Response (JTR) filters with higher order can be used to achieve better equalization.
- FIR Finite Impulse Response
- JTR Infinite Impulse Response
- the first sampling-rate converter 74 either alone or as part of the input ADC, has an output rate equal to the intermediate sampling rate.
- the second input sampling-rate converter 78 can be eliminated.
- the equalizer 76 may also be eliminated leaving only the input delta-sigma modulator 72 and the first input sampling-rate converter 74. Recall that the input delta-sigma modulator 72 and the first input sampling-rate converter 74 may also be replaced with the input ADC. If so, this would leave the input ADC as the only element of the input processor 52.
- the INPUT signal is a digital signal (Din). If so, then there will be no need for the input delta-sigma modulator 72 and the first input sampling-rate converter 74 shown. These can be eliminated. That leaves the equalizer 76 and the second input sampling-rate converter 78. Of course since there is now only one, the term second could be dropped leaving only an input sampling-rate converter 78. Depending on the circumstances, these remaining two elements may appear in one of four configurations, that is, the one, the other, both, and neither. When the sampling rate of the digital signal is already at the intermediate rate, then there will be no need for the sampling-rate converter 78.
- the input processor 52 may merely pass the signal through to the first summation node 66 of FIGS. 4 and 5 without transformation. Nevertheless, for the sake of uniformity, the signal is referred to as the processed digital input signal to distinguish it from the generalized INPUT signal which may or may not require transformation.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Compression, Expansion, Code Conversion, And Decoders (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP02744641A EP1417860A2 (en) | 2001-06-26 | 2002-06-25 | Method and apparatus for minimizing latency in digital signal processing systems |
JP2003509821A JP2004537890A (en) | 2001-06-26 | 2002-06-25 | Method and apparatus for minimizing latency in digital signal processing systems |
CA002451999A CA2451999A1 (en) | 2001-06-26 | 2002-06-25 | Method and apparatus for minimizing latency in digital signal processing systems |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US30130801P | 2001-06-26 | 2001-06-26 | |
US60/301,308 | 2001-06-26 | ||
US10/179,930 US6717537B1 (en) | 2001-06-26 | 2002-06-24 | Method and apparatus for minimizing latency in digital signal processing systems |
US10/179,930 | 2002-06-25 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2003003789A2 true WO2003003789A2 (en) | 2003-01-09 |
WO2003003789A3 WO2003003789A3 (en) | 2004-03-11 |
Family
ID=26875826
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2002/020223 WO2003003789A2 (en) | 2001-06-26 | 2002-06-25 | Method and apparatus for minimizing latency in digital signal processing systems |
Country Status (6)
Country | Link |
---|---|
US (1) | US6717537B1 (en) |
EP (1) | EP1417860A2 (en) |
JP (1) | JP2004537890A (en) |
CN (1) | CN1541496A (en) |
CA (1) | CA2451999A1 (en) |
WO (1) | WO2003003789A2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007129003A1 (en) * | 2006-04-12 | 2007-11-15 | Wolfson Microelectronics Plc | Digital circuit arrangements for ambient noise-reduction |
GB2465681A (en) * | 2006-04-12 | 2010-06-02 | Wolfson Microelectronics Plc | Digital filter arrangements for ambient noise-reduction |
Families Citing this family (27)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1449338A1 (en) * | 2001-11-21 | 2004-08-25 | Koninklijke Philips Electronics N.V. | Adaptive equalizer operating at a sampling rate asynchronous to the data rate |
US7599451B2 (en) * | 2005-05-11 | 2009-10-06 | Sigmatel, Inc. | Sample rate conversion module and applications thereof |
US7899135B2 (en) * | 2005-05-11 | 2011-03-01 | Freescale Semiconductor, Inc. | Digital decoder and applications thereof |
US8611553B2 (en) * | 2010-03-30 | 2013-12-17 | Bose Corporation | ANR instability detection |
US8144890B2 (en) * | 2009-04-28 | 2012-03-27 | Bose Corporation | ANR settings boot loading |
JP2010259008A (en) * | 2009-04-28 | 2010-11-11 | Toshiba Corp | Signal processing apparatus, sound apparatus, and signal processing method |
US8315405B2 (en) * | 2009-04-28 | 2012-11-20 | Bose Corporation | Coordinated ANR reference sound compression |
US8208650B2 (en) * | 2009-04-28 | 2012-06-26 | Bose Corporation | Feedback-based ANR adjustment responsive to environmental noise levels |
US8073151B2 (en) * | 2009-04-28 | 2011-12-06 | Bose Corporation | Dynamically configurable ANR filter block topology |
US8073150B2 (en) * | 2009-04-28 | 2011-12-06 | Bose Corporation | Dynamically configurable ANR signal processing topology |
US8345888B2 (en) * | 2009-04-28 | 2013-01-01 | Bose Corporation | Digital high frequency phase compensation |
US8155334B2 (en) * | 2009-04-28 | 2012-04-10 | Bose Corporation | Feedforward-based ANR talk-through |
US8532310B2 (en) * | 2010-03-30 | 2013-09-10 | Bose Corporation | Frequency-dependent ANR reference sound compression |
US8184822B2 (en) * | 2009-04-28 | 2012-05-22 | Bose Corporation | ANR signal processing topology |
US8280066B2 (en) * | 2009-04-28 | 2012-10-02 | Bose Corporation | Binaural feedforward-based ANR |
US8165313B2 (en) * | 2009-04-28 | 2012-04-24 | Bose Corporation | ANR settings triple-buffering |
US8090114B2 (en) * | 2009-04-28 | 2012-01-03 | Bose Corporation | Convertible filter |
US8085946B2 (en) * | 2009-04-28 | 2011-12-27 | Bose Corporation | ANR analysis side-chain data support |
US8472637B2 (en) | 2010-03-30 | 2013-06-25 | Bose Corporation | Variable ANR transform compression |
US8737636B2 (en) | 2009-07-10 | 2014-05-27 | Qualcomm Incorporated | Systems, methods, apparatus, and computer-readable media for adaptive active noise cancellation |
US9401158B1 (en) | 2015-09-14 | 2016-07-26 | Knowles Electronics, Llc | Microphone signal fusion |
US9779716B2 (en) | 2015-12-30 | 2017-10-03 | Knowles Electronics, Llc | Occlusion reduction and active noise reduction based on seal quality |
US9830930B2 (en) | 2015-12-30 | 2017-11-28 | Knowles Electronics, Llc | Voice-enhanced awareness mode |
US9812149B2 (en) | 2016-01-28 | 2017-11-07 | Knowles Electronics, Llc | Methods and systems for providing consistency in noise reduction during speech and non-speech periods |
US10284332B2 (en) * | 2017-03-03 | 2019-05-07 | Intel IP Corporation | Spur cancelation using inverse spur injection |
CN113439159A (en) * | 2018-12-21 | 2021-09-24 | 维斯塔斯风力系统集团公司 | Wind turbine control based on optimized and non-optimized controller routines |
US11386882B2 (en) | 2020-02-12 | 2022-07-12 | Bose Corporation | Computational architecture for active noise reduction device |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1994011953A2 (en) * | 1992-11-11 | 1994-05-26 | Noise Buster Technology | Active noise cancellation system |
US5638022A (en) * | 1992-06-25 | 1997-06-10 | Noise Cancellation Technologies, Inc. | Control system for periodic disturbances |
US5815582A (en) * | 1994-12-02 | 1998-09-29 | Noise Cancellation Technologies, Inc. | Active plus selective headset |
Family Cites Families (79)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4185168A (en) | 1976-05-04 | 1980-01-22 | Causey G Donald | Method and means for adaptively filtering near-stationary noise from an information bearing signal |
US4025721A (en) | 1976-05-04 | 1977-05-24 | Biocommunications Research Corporation | Method of and means for adaptively filtering near-stationary noise from speech |
US4122303A (en) | 1976-12-10 | 1978-10-24 | Sound Attenuators Limited | Improvements in and relating to active sound attenuation |
US4249128A (en) | 1978-02-06 | 1981-02-03 | White's Electronics, Inc. | Wide pulse gated metal detector with improved noise rejection |
US4309570A (en) | 1979-04-05 | 1982-01-05 | Carver R W | Dimensional sound recording and apparatus and method for producing the same |
US4603429A (en) | 1979-04-05 | 1986-07-29 | Carver R W | Dimensional sound recording and apparatus and method for producing the same |
JPS57500802A (en) | 1980-04-24 | 1982-05-06 | ||
US4473906A (en) | 1980-12-05 | 1984-09-25 | Lord Corporation | Active acoustic attenuator |
AU550700B2 (en) | 1981-06-12 | 1986-03-27 | Chaplin Patents Holding Co. Ltd | Method and apparatus for reducing repetitive noise entering the ear |
US4423442A (en) | 1981-12-31 | 1983-12-27 | General Electric Company | Tape recorder utilizing an integrated circuit |
US4455675A (en) | 1982-04-28 | 1984-06-19 | Bose Corporation | Headphoning |
US4494074A (en) | 1982-04-28 | 1985-01-15 | Bose Corporation | Feedback control |
US4622660A (en) | 1983-02-17 | 1986-11-11 | Cowans Kenneth W | Systems and methods for signal compensation |
GB8317086D0 (en) | 1983-06-23 | 1983-07-27 | Swinbanks M A | Attenuation of sound waves |
US4644581A (en) | 1985-06-27 | 1987-02-17 | Bose Corporation | Headphone with sound pressure sensing means |
US4868870A (en) | 1985-10-01 | 1989-09-19 | Schrader Daniel J | Servo-controlled amplifier and method for compensating for transducer nonlinearities |
US4783818A (en) | 1985-10-17 | 1988-11-08 | Intellitech Inc. | Method of and means for adaptively filtering screeching noise caused by acoustic feedback |
US4658932A (en) | 1986-02-18 | 1987-04-21 | Billingsley Michael S J C | Simulated binaural recording system |
FR2595498B1 (en) | 1986-03-07 | 1989-06-02 | Centre Nat Rech Scient | METHODS AND DEVICES FOR MITIGATING EXTERNAL NOISE ARISING AT TYMPAN AND IMPROVING THE INTELLIGIBILITY OF ELECTROACOUSTIC COMMUNICATIONS |
US4731850A (en) | 1986-06-26 | 1988-03-15 | Audimax, Inc. | Programmable digital hearing aid system |
US4879749A (en) | 1986-06-26 | 1989-11-07 | Audimax, Inc. | Host controller for programmable digital hearing aid system |
US4736751A (en) | 1986-12-16 | 1988-04-12 | Eeg Systems Laboratory | Brain wave source network location scanning method and system |
GB8717043D0 (en) | 1987-07-20 | 1987-08-26 | Plessey Co Plc | Noise reduction systems |
JPH0797810B2 (en) | 1987-09-30 | 1995-10-18 | シャープ株式会社 | Facsimile read / write head drive system |
US4922542A (en) | 1987-12-28 | 1990-05-01 | Roman Sapiejewski | Headphone comfort |
US5181252A (en) | 1987-12-28 | 1993-01-19 | Bose Corporation | High compliance headphone driving |
US4985925A (en) | 1988-06-24 | 1991-01-15 | Sensor Electronics, Inc. | Active noise reduction system |
US4827280A (en) | 1988-08-09 | 1989-05-02 | A. B. Dick Company | Flow rate control system |
US4878188A (en) | 1988-08-30 | 1989-10-31 | Noise Cancellation Tech | Selective active cancellation system for repetitive phenomena |
US4939600A (en) | 1989-01-05 | 1990-07-03 | Micropolis Corporation | Efficient head positioner power amplifier |
US5107379A (en) | 1989-01-24 | 1992-04-21 | Maxtor Corporation | Read channel detector with improved signaling speed |
US5222189A (en) | 1989-01-27 | 1993-06-22 | Dolby Laboratories Licensing Corporation | Low time-delay transform coder, decoder, and encoder/decoder for high-quality audio |
US5001763A (en) | 1989-08-10 | 1991-03-19 | Mnc Inc. | Electroacoustic device for hearing needs including noise cancellation |
US5259033A (en) | 1989-08-30 | 1993-11-02 | Gn Danavox As | Hearing aid having compensation for acoustic feedback |
NO169689C (en) | 1989-11-30 | 1992-07-22 | Nha As | PROGRAMMABLE HYBRID HEARING DEVICE WITH DIGITAL SIGNAL TREATMENT AND PROCEDURE FOR DETECTION AND SIGNAL TREATMENT AT THE SAME. |
US5164984A (en) | 1990-01-05 | 1992-11-17 | Technology Management And Ventures, Ltd. | Hands-free telephone assembly |
US5109410A (en) | 1990-01-05 | 1992-04-28 | Technology Management And Ventures, Ltd. | Two-line, hands-free telephone system |
US5105377A (en) | 1990-02-09 | 1992-04-14 | Noise Cancellation Technologies, Inc. | Digital virtual earth active cancellation system |
US5182774A (en) | 1990-07-20 | 1993-01-26 | Telex Communications, Inc. | Noise cancellation headset |
WO1992005538A1 (en) | 1990-09-14 | 1992-04-02 | Chris Todter | Noise cancelling systems |
US5083538A (en) | 1991-01-15 | 1992-01-28 | Brunswick Corporation | One-piece air intake and flywheel cover for an outboard marine engine |
US5159639A (en) | 1991-02-19 | 1992-10-27 | Shannon Clark W | Assistive listening device |
US5177755A (en) | 1991-05-31 | 1993-01-05 | Amoco Corporation | Laser feedback control circuit and method |
US5267321A (en) | 1991-11-19 | 1993-11-30 | Edwin Langberg | Active sound absorber |
US5287398A (en) | 1991-11-20 | 1994-02-15 | Nigel C. Briault | Remotely accessible security controlled audio link |
WO1993023942A1 (en) | 1992-05-11 | 1993-11-25 | Jabra Corporation | Unidirectional ear microphone and method |
US5251263A (en) | 1992-05-22 | 1993-10-05 | Andrea Electronics Corporation | Adaptive noise cancellation and speech enhancement system and apparatus therefor |
JP3097340B2 (en) | 1992-08-19 | 2000-10-10 | ソニー株式会社 | Headphone equipment |
US5381485A (en) | 1992-08-29 | 1995-01-10 | Adaptive Control Limited | Active sound control systems and sound reproduction systems |
GB2274757A (en) | 1993-01-28 | 1994-08-03 | Secr Defence | Ear defenders employing active noise control |
US5361303A (en) | 1993-04-01 | 1994-11-01 | Noise Cancellation Technologies, Inc. | Frequency domain adaptive control system |
US5481615A (en) | 1993-04-01 | 1996-01-02 | Noise Cancellation Technologies, Inc. | Audio reproduction system |
US5452361A (en) | 1993-06-22 | 1995-09-19 | Noise Cancellation Technologies, Inc. | Reduced VLF overload susceptibility active noise cancellation headset |
AU7355594A (en) | 1993-06-23 | 1995-01-17 | Noise Cancellation Technologies, Inc. | Variable gain active noise cancellation system with improved residual noise sensing |
US5539831A (en) | 1993-08-16 | 1996-07-23 | The University Of Mississippi | Active noise control stethoscope |
US5497426A (en) | 1993-11-15 | 1996-03-05 | Jay; Gregory D. | Stethoscopic system for high-noise environments |
US5604813A (en) | 1994-05-02 | 1997-02-18 | Noise Cancellation Technologies, Inc. | Industrial headset |
WO1996011466A1 (en) | 1994-10-06 | 1996-04-18 | Duke University | Feedback acoustic energy dissipating device with compensator |
US5602928A (en) | 1995-01-05 | 1997-02-11 | Digisonix, Inc. | Multi-channel communication system |
US5523715A (en) | 1995-03-10 | 1996-06-04 | Schrader; Daniel J. | Amplifier arrangement and method and voltage controlled amplifier and method |
US5850453A (en) | 1995-07-28 | 1998-12-15 | Srs Labs, Inc. | Acoustic correction apparatus |
US6072884A (en) | 1997-11-18 | 2000-06-06 | Audiologic Hearing Systems Lp | Feedback cancellation apparatus and methods |
US5727566A (en) | 1996-01-23 | 1998-03-17 | Howard S. Leight And Associates, Inc. | Trackable earplug |
US5793875A (en) | 1996-04-22 | 1998-08-11 | Cardinal Sound Labs, Inc. | Directional hearing system |
US5999631A (en) * | 1996-07-26 | 1999-12-07 | Shure Brothers Incorporated | Acoustic feedback elimination using adaptive notch filter algorithm |
AUPO316196A0 (en) | 1996-10-23 | 1996-11-14 | Lake Dsp Pty Limited | Method and apparatus for processing sigma-delta modulated signals |
US6181801B1 (en) | 1997-04-03 | 2001-01-30 | Resound Corporation | Wired open ear canal earpiece |
US6445799B1 (en) | 1997-04-03 | 2002-09-03 | Gn Resound North America Corporation | Noise cancellation earpiece |
US6078672A (en) | 1997-05-06 | 2000-06-20 | Virginia Tech Intellectual Properties, Inc. | Adaptive personal active noise system |
US5965850A (en) | 1997-07-10 | 1999-10-12 | Fraser Sound Scoop, Inc. | Non-electronic hearing aid |
WO1999005998A1 (en) | 1997-07-29 | 1999-02-11 | Telex Communications, Inc. | Active noise cancellation aircraft headset system |
US6219427B1 (en) | 1997-11-18 | 2001-04-17 | Gn Resound As | Feedback cancellation improvements |
US6396930B1 (en) | 1998-02-20 | 2002-05-28 | Michael Allen Vaudrey | Active noise reduction for audiometry |
US6163610A (en) | 1998-04-06 | 2000-12-19 | Lucent Technologies Inc. | Telephonic handset apparatus having an earpiece monitor and reduced inter-user variability |
US6160893A (en) | 1998-07-27 | 2000-12-12 | Saunders; William Richard | First draft-switching controller for personal ANR system |
US6208279B1 (en) | 1998-08-17 | 2001-03-27 | Linear Technology Dorporation | Single-cycle oversampling analog-to-digital converter |
US6173063B1 (en) | 1998-10-06 | 2001-01-09 | Gn Resound As | Output regulator for feedback reduction in hearing aids |
EP1097607B1 (en) * | 1999-02-05 | 2003-04-16 | Widex A/S | Hearing aid with beam forming properties |
US6373953B1 (en) * | 1999-09-27 | 2002-04-16 | Gibson Guitar Corp. | Apparatus and method for De-esser using adaptive filtering algorithms |
-
2002
- 2002-06-24 US US10/179,930 patent/US6717537B1/en not_active Expired - Lifetime
- 2002-06-25 CA CA002451999A patent/CA2451999A1/en not_active Abandoned
- 2002-06-25 CN CNA028157869A patent/CN1541496A/en active Pending
- 2002-06-25 JP JP2003509821A patent/JP2004537890A/en active Pending
- 2002-06-25 EP EP02744641A patent/EP1417860A2/en not_active Withdrawn
- 2002-06-25 WO PCT/US2002/020223 patent/WO2003003789A2/en not_active Application Discontinuation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5638022A (en) * | 1992-06-25 | 1997-06-10 | Noise Cancellation Technologies, Inc. | Control system for periodic disturbances |
WO1994011953A2 (en) * | 1992-11-11 | 1994-05-26 | Noise Buster Technology | Active noise cancellation system |
US5815582A (en) * | 1994-12-02 | 1998-09-29 | Noise Cancellation Technologies, Inc. | Active plus selective headset |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007129003A1 (en) * | 2006-04-12 | 2007-11-15 | Wolfson Microelectronics Plc | Digital circuit arrangements for ambient noise-reduction |
GB2465681A (en) * | 2006-04-12 | 2010-06-02 | Wolfson Microelectronics Plc | Digital filter arrangements for ambient noise-reduction |
GB2465681B (en) * | 2006-04-12 | 2010-12-15 | Wolfson Microelectronics Plc | Digital circuit arrangements for ambient noise-reduction |
US8165312B2 (en) | 2006-04-12 | 2012-04-24 | Wolfson Microelectronics Plc | Digital circuit arrangements for ambient noise-reduction |
US8644523B2 (en) | 2006-04-12 | 2014-02-04 | Wolfson Microelectronics Plc | Digital circuit arrangements for ambient noise-reduction |
US9558729B2 (en) | 2006-04-12 | 2017-01-31 | Cirrus Logic, Inc. | Digital circuit arrangements for ambient noise-reduction |
US10319361B2 (en) | 2006-04-12 | 2019-06-11 | Cirrus Logic, Inc. | Digital circuit arrangements for ambient noise-reduction |
US10818281B2 (en) | 2006-04-12 | 2020-10-27 | Cirrus Logic, Inc. | Digital circuit arrangements for ambient noise-reduction |
Also Published As
Publication number | Publication date |
---|---|
CN1541496A (en) | 2004-10-27 |
US6717537B1 (en) | 2004-04-06 |
WO2003003789A3 (en) | 2004-03-11 |
EP1417860A2 (en) | 2004-05-12 |
CA2451999A1 (en) | 2003-01-09 |
JP2004537890A (en) | 2004-12-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6717537B1 (en) | Method and apparatus for minimizing latency in digital signal processing systems | |
US11205412B1 (en) | Hybrid active noise cancellation filter adaptation | |
KR101393756B1 (en) | Digital filter circuit, digital filter program and noise canceling system | |
US8611551B1 (en) | Low latency active noise cancellation system | |
US8345888B2 (en) | Digital high frequency phase compensation | |
CN110603582A (en) | Real-time acoustic processor | |
US11189261B1 (en) | Hybrid active noise control system | |
GB2455828A (en) | Noise cancellation system with adaptive filter and two different sample rates | |
WO2009081193A1 (en) | Noise cancelling system with adaptive high-pass filter | |
CN109600698A (en) | The audio reproduction that noise reduces | |
JP2007522754A (en) | Acoustic feedback suppression | |
JP2000217187A (en) | Receiver for telephone set adopting feedforward noise cancellation | |
US5953431A (en) | Acoustic replay device | |
US11107453B2 (en) | Anti-noise signal generator | |
US10186249B1 (en) | Active noise cancellation system | |
US10904661B2 (en) | Low delay decimator and interpolator filters | |
US11264004B2 (en) | Parallel noise cancellation filters | |
WO2009081184A1 (en) | Noise cancellation system and method with adjustment of high pass filter cut-off frequency | |
US20140112491A1 (en) | Method and Apparatus for a Configurable Active Noise Canceller | |
AU2002345900A1 (en) | Method and apparatus for minimizing latency in digital signal processing systems | |
TWI754555B (en) | Improved noise partition hybrid type anc system | |
US10783870B1 (en) | Audio playback device and method having noise-cancelling mechanism | |
NL2018617B1 (en) | Intra ear canal hearing aid | |
CN112312250B (en) | Audio playing device and method with anti-noise mechanism | |
US20230199122A1 (en) | Echo cancellation |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A2 Designated state(s): AU CA CN JP |
|
AL | Designated countries for regional patents |
Kind code of ref document: A2 Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
WWE | Wipo information: entry into national phase |
Ref document number: 2451999 Country of ref document: CA |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2003509821 Country of ref document: JP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2002345900 Country of ref document: AU |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2002744641 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 20028157869 Country of ref document: CN |
|
WWP | Wipo information: published in national office |
Ref document number: 2002744641 Country of ref document: EP |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 2002744641 Country of ref document: EP |