1. Active Noise Control A site specializing in active noise control, with news, suggested reading, and links brought to you by Signal Systems Corporation. What is active noise control? http://www.signalsystemscorp.com/ancindex.htm

Home Projects Contact Personnel ... Links [ ANC ] Downloads Home ANC News Active Noise Control Organizations ... ANC Status Active Noise Control quiets offensive noise by using cancellation techniques, or anti-sound. Signal Systems Corporation's mission is to help quiet irritating noises so you can have a more peaceful life. This web site is designed to give the active noise community a common source for information about this technology, its applications and suppliers. Please use the feedback link at the bottom of each page to let us know how we can improve this site. What is active noise control? Check out the ANC FAQ Where is active noise control technology going ? Read our discussion about commercializing ANC technology

2. Redirection University of Adelaide. Active noise and vibration control group. Current research projects and publications. http://www.mecheng.adelaide.edu.au/anvc/home.html

Hold on You are being redirected to the ANVC homepage You will be redirected immediately

3. Active Noise Control active noise control. One of the less desirable aspects of modern technology has been the generation of unwanted noise. http://www.me.berkeley.edu/active_noise_control.html

Active Noise Control One of the less desirable aspects of modern technology has been the generation of unwanted noise. Noise can be produced by manufacturing machinery, from air and fluid flows, from vibrations transmitted within structures, etc. This noise can reduce an individual's ability to receive acoustic information and induce listening fatigue and/or permanent hearing damage. At Berkeley, researchers are focusing on active means to ameliorate the problems of unwanted noise. Research Areas Control strategies for noise reduction Acoustic tailoring Piezo sensors and actuators Transient wave control Structural/acoustic response prediction Research Facilities Active Noise Control Laboratory Faculty K. Hedrick A. Packard B. Tongue Professors Packard, Hedrick, and Tongue (from left to right) examine the experimental sound box used to test methods for reducing noise. Latest update: June 18, 1996

4. Analog Feedback Active Noise Control Analog Feedback active noise control. 0) Introduction to single channel feedback noise control Nelson and Elliott and Section 6.2 from active noise control Systems, Kuo and Morgan http://ourworld.compuserve.com/homepages/discoveryengineering/fanc1.htm

Analog Feedback Active Noise Control Introduction to single channel feedback noise control The system consists of a microphone sensor, a loudspeaker actuator, and an equalizer to correct for the delay from the speaker to the microphone and for the transfer function of the speaker itself. The microphone is usually placed close to the speaker. The system transfer function is increasingly difficult to equalize as the mic moves away from the speaker (the phase change goes from gradual over the bandwidth of interest to very rapid). A disturbance input at the sensor (low frequency acoustic noise) can be attenuated by the proper choice of equalization. The zone of silence around the sensor is approximately 1/10 th of the wavelength of the noise to be attenuated. see Sections 7.3, 7.4 and 7.7 from Active Control of Sound , Nelson and Elliott and Section 6.2 from Active Noise Control Systems , Kuo and Morgan Pick the problem For example, reduce a 100 Hz tone by at least 10 dB in the vicinity of an error microphone Assemble the HW needed Noise generator to measure the system transfer function - use an analyzer with a built in source, buy, or build your own

5. Active Noise Control FAQ V1996-03-14 active noise control FAQ v199603-14. This FAQ has four purposes * Provide concise, accurate answers to common questions about active noise control. http://www.faqs.org/faqs/active-noise-control-faq/

Usenet FAQs Search Web FAQs Documents ... RFC Index Active Noise Control FAQ v1996-03-14 There are reader questions on this topic! Help others by sharing your knowledge From: ruckman@xis.com (Dr. Chris Ruckman) Newsgroups: alt.sci.physics.acoustics comp.dsp ruckman@xis.com mail-server@rtfm.mit.edu (send usenet/news.answers/active-noise-control-faq) Like most FAQs, this is a living, evolving document. Please e-mail contributions, comments, praise, and criticisms to the FAQ maintainer (ruckman@oasys.dt.navy.mil) or post to news:alt.sci.physics.acoustics . In particular, please contribute the following: * Companies/universities that teach courses on active control * Companies that sell active control products * Interesting references from the general literature * Comments from readers who do not know much about acoustics To cite this FAQ as a reference, I suggest a citation like this: Ruckman, C.E. (1995) "Frequently Asked Questions: Active Noise Control," Internet FAQ document. Available via anonymous ftp from ftp://rtfm.mit.edu/pub/usenet/news.answers/, or via Usenet in news:news.answers. - - - - - - - - - - - - - - - - - - - - - - - Subject: 1.3. Contributors The following people contributed to the discussions upon which this FAQ is based: * rtm@sabine.acs.psu.edu

6. Active Control active noise control. Active Control eXperts. Active Control eXperts (ACX) is a rapidly growing product design and manufacturing company specializing in applying smart materials, such as piezoelectrics, and active control technology. ANC, from Causal Systems, makes active noise control accessible to engineers, researchers, consultants http://www.ecgcorp.com/velav/vldocs/active.html

Active Noise Control Active Control eXperts Active Control eXperts (ACX) is a rapidly growing product design and manufacturing company specializing in applying smart materials, such as piezoelectrics, and active control technology. ACX provides engineering services and components to companies that need actuators, sensors, vibration reduction, and motion control in their products. Causal Systems EZ-ANC II is a product released in 2000 that has a Windows graphical user interface. It is based on the Analog Devices floating point Sharc processor, has 10 inputs and 10 outputs, is suitable for random and periodic noise control, and is supplied in an enclosure with power supply. Lord Corporation Lord Corporation's NVX Active Systems solve a range of vibration, motion and noise control challenges. Typical systems feature a controller, actuators and sensors which work together to eliminate unwanted vibration and noise or to produce precise forces or motions, depending on the application. NCT Group, Inc. NCT is a leading technology company dedicated to the development and commercialization of Active Wave Management applicationsthe electronic manipulation of sound and signal waves to reduce noise, improve signal-to-noise ratios and enhance sound quality. QRDC, Inc.

7. Active Noise Control FAQ V1996-03-14 FAQ This FAQ describes active noise control, a novel method for controlling unwanted sound and vibration. Frequently Asked Questions active noise control SUMMARY The FAQ you are now reading discusses active noise control, a novel way of using http://www.non.com/news.answers/active-noise-control-faq.html

Non.com FAQ Mirrors Prev: acedb-faq Next: advertisers-blacklist Active Noise Control FAQ v1996-03-14 Frequently Asked Questions: Active noise control SUMMARY: The FAQ you are now reading discusses active noise control, a novel way of using basic physics to control noise and/or vibration. What is an FAQ, you say? Well, the Internet supports thousands of "newsgroups" discussion forums covering every imaginable topic. An FAQ (Frequently Asked Questions list) is a summary written to answer specific questions that arise repeatedly in the newsgroups. This particular FAQ was written for the newsgroups news: alt.sci.physics.acoustics and news: comp.dsp Subject: 1. Introduction Subject: 1.1. What's new in the Active Control FAQ comp.dsp 1994/12/22 revised list of applications (2.8) 1994/12/12 added new references 1994/10/04 expanded description of mechanisms; corrected typo’s 1994/06/14 initial release - - - - - - - - - - - - - - - - - - - - - - - Subject: 1.2. Finding the most recent FAQ The Active Noise Control FAQ is updated monthly; see the version date cited above. You have several options to obtain the latest version: * Usenet: the FAQ is posted monthly to these newsgroups: news: alt.sci.physics.acoustics

8. Active Noise Control FAQ active noise control FAQ. The FAQ you are now reading discusses active noise control, a novel way of using basic physics to control noise and/or vibration. http://www.erols.com/ruckman/ancfaq.htm

Active Noise Control FAQ Winner of the Acoustical Society of America Science Writing Award Version 2001-02-27 The "FAQ" you are now reading discusses active noise control, a novel way of using basic physics to control noise and/or vibration. What is an FAQ, you say? It's a "Frequently Asked Questions list." The Internet supports thousands of "newsgroups" discussion forums covering every imaginable topic. When certain questions tend to get asked over and over again, it's common to assemble the answers into a list for easy reference. This particular FAQ was written for the newsgroups news:alt.sci.physics.acoustics and news:comp.dsp to serve four purposes: Provide concise, accurate answers to common questions about active noise control. Dispel popular misconceptions about what active noise control can and cannot do. Refer readers to web links, technical references, and other sources of information. Stimulate public interest in acoustics. You can use the links at left to read the FAQ, or you can click here to download the entire FAQ as a text file.

9. Active Noise Control FAQ Provides answers to common questions about active noise control including a discussion of popular misconceptions about what active noise control can and cannot do. http://users.erols.com/ruckman/ancfaq.htm

Active Noise Control FAQ Winner of the Acoustical Society of America Science Writing Award Version 2001-02-27 The "FAQ" you are now reading discusses active noise control, a novel way of using basic physics to control noise and/or vibration. What is an FAQ, you say? It's a "Frequently Asked Questions list." The Internet supports thousands of "newsgroups" discussion forums covering every imaginable topic. When certain questions tend to get asked over and over again, it's common to assemble the answers into a list for easy reference. This particular FAQ was written for the newsgroups news:alt.sci.physics.acoustics and news:comp.dsp to serve four purposes: Provide concise, accurate answers to common questions about active noise control. Dispel popular misconceptions about what active noise control can and cannot do. Refer readers to web links, technical references, and other sources of information. Stimulate public interest in acoustics. You can use the links at left to read the FAQ, or you can click here to download the entire FAQ as a text file.

10. Publications On Active Noise And Vibration Control -- Scott C. Douglas Active Noise and Vibration Control (ANVC) active noise control, and its cousin, active vibration control, attempt to cancel an unwanted ``noise'' acoustical wave by injecting http://www.seas.smu.edu/~douglas/pubanvc.html

Active Noise and Vibration Control (ANVC) Active noise control, and its cousin, active vibration control, attempt to cancel an unwanted ``noise'' acoustical wave by injecting an equal-but-opposite ``anti-noise''acoustical wave into the medium, thereby attenuating the wave via destructive interference. The origins of ANVC date back to at least 1936, when P. Leug patented the idea for sound control. It tooks nearly fifty years, however, to obtain what might be called successful ANVC, due to the level of electronic precision required to create an anti-noise signal with any great fidelity. Today, anti-noise headsets abound (I have a very cute set of Sony earbud-style `phones from Japan); these are mostly analog systems. Large-scale quieting requires the use of adaptive digital signal processing technology in all but the simplest acoustic environments. I began my study of ANVC as a summer hire at SRI International, Menlo Park, CA, in 1992. While working in the Acoustics and Radar Technology Laboratory, I helped develop the algorithms and guide software code developers to implement a simple one-input, one-output, one-error active noise control system that illustrated some of the advantages that simple adaptive processing has over more-costly off-line calibration methods. I also developed the multichannel extensions of the algorithms and wrote an internal SRI report that helped others to design a real-time multichannel active noise control system for reverberant room noise control. After joining the University of Utah, I remained as a consultant to SRI, developing normalized LMS algorithms for multichannel active noise control and studying simplified

11. ANC News active noise control News. Selected events in active noise control. Digisonix has been reorganized after Nelson Industries was bought by Cummins Engine. http://www.signalsystemscorp.com/anc_news.htm

Home Projects Contact Personnel ... Home [ ANC News ] Active Noise Control Organizations ANC FAQ MATLAB Active Noise Control Toolbox Active Noise Control e-Store ... ANC Status Active Noise Control News Selected events in Active Noise Control Digisonix has been re-organized after Nelson Industries was bought by Cummins Engine. The focus of Digisonix has migrated from HVAC noise reduction to internal combustion exhaust noise reduction. The technical staff has reduced in size. Cymer, a leading supplier of excimer light sources used in semiconductor manufacturing, has completed its acquistion of ACX (Active Control eXperts), a leading developer of active vibration reduction products. ACX will be focused on reducing nano-scale vibration in next generation semiconducter capital equipment. Before focusing on semiconducter manufacturing applications, ACX's commerical plans included vibration reduction solutions for sporting equipment (bats, snowboards, etc.). More information can be found at ACX Labs web site: ACX Website

12. The Active Noise Control Of A Light Aircraft Cabin Interior; A Work In Progress. The active noise control of a Light Aircraft Cabin Interior; A work in progress. Colin Kestell, Ben Cazzolato and Colin H. Hansen http://www.mecheng.adelaide.edu.au/anvc/publications/papers/1998/anaheim.html

The Active Noise Control of a Light Aircraft Cabin Interior; A work in progress. Colin Kestell Ben Cazzolato and Colin H. Hansen School of Mechanical Engineering, The University of Adelaide, South Australia 5005, Australia Presented at the Institute of Mechanical Engineers Conference : IMECH98, November, Anaheim. Abstract This material is now only available to staff and students of the University of Adelaide. Should you wish to receive a copy, please contact the ANVC Group Webmaster PDF File format (303kb) This page has been accessed : Since 9/3/99. Return to ANVC Homepage

13. Industrial Enclosure, Electronic Boxes, Plastic Boxes, Aluminum Enclosures, Plas Bosco Italia S.p.A plans, builds and implements noise reduction and active noise control systems http://www.industrial-enclosures.com

INDUSTRIAL ENCLOSURES and ELECTRONIC BOXES as ALUMINUM or PLASTIC ENCLOSURE STANDARD or CUSTOMIZED HOUSINGS and CABINETS To make it easier for you to find the type of enclosure you are looking for with our great variety of industrial enclosures, we have put together the enclosures in groups according to their usage. Via the buttons on the left you get directly to the respective index pages. In case you don’t find the desired industrial enclosure, please just send us an email, our range of products is stretched constantly. New product lines: Enclosure line ISAG new Aluminum enclosure serie Profile enclosure line PRIOLINE We can deliver more than 500 different types of industrial enclosures with front foils or foil keyboards varnishing / powder coating mecanical processing printing and many more Are you looking for additional products and services all around your enclosures? In co-operation with other companies, we have put together www.Gehaeuse.info

14. Center For Applied Control Mission is to promote and conduct research in a broad spectrum of fields including acoustics, aeroacoustics, aeroelasticity, structural dynamics, nonlinear systems, pattern recognition, seismic structural vibration, fuzzy logic active control applications, active noise control, and active magnetic bearings. http://edisto.egr.duke.edu/~hpgavin/CAC/

15. Active Noise Control : Internet Resources active noise control Internet Resources Research Publications Companies Conferences Misc . . If you want to add a link http://www.hh.se/staff/wolfgang/orpheus/anclinks.html

Active Noise Control: Internet Resources Research Publications Companies Conferences ... Misc If you want to add a link, just mail it to Wolfgang.Svensson@ide.hh.se Research Intelligent Systems lab., Halmstad University, (Swe) Centre for Acoustics and Vibration Penn State University,(USA) Institute of Sound and Vibration Research, University of Southampton,(UK) Mechanical Engineering , Trinity College, Dublin, (EIRE) University of Utah (USA) Signal Processing Division, University of Strathclyde, Glasgow, (Sco) Department of Signal Processing, University of Karlskrona Ronneby, (Sweden) Acoustics and Signal Processing Institute for Micro structural Sciences National Research Council of Canada Bldg, Ottawa (Can) Laboratories , Marseilles, (Fra) VIRGINIA TECH. Mechanical Engineering Department. (USA) Department of Mechanical Engineering , University of Adelaide, (Australia) Production Engineering, Machine Design and Automation , K.U.Leuven (B) Fraunhofer institut Stuttgart (GER.) TNO TPD research institute of Applied Physics Delft (NL) Publication Books, CD and video publications of the

16. Principle Of Active Noise Control vibrations. TechnoFirst industrial leader in active control of noise and vibration. What s active noise control ? Definition. The http://www.technofirst.com/us/antibruit_us.htm

What's Active Noise Control ? Definition The principle of active sound control has been known for a long time, but its application to real situations is often difficult and raises numerous difficulties. It consists of canceling an undesirable noise by superposing an inverse noise, which results in the destructive interference of the pressure waves. Sound is driven by the propagation of a pressure wave. It is possible to cancel this wave by adding its opposite As you can see on the following animation, the resulting wave if very weak. External noise Analyze and signal processing Resulting wave How is it realized ? First of all, the creation of an opposite sound requires the use of at least one noise source (loud-speaker). Sensors (microphones) are also needed to gather information about the acoustic field. The characteristics of the sources and sensors are closely related to the application concerned. Finally, the heart of noise control is an electronic system (analog or digital), which generates the canceling noise which will interfere with the undesirable noise.

17. Hi-Fi Headset With Active Noise Control LITE™ Audio Headphone with Active Noise Reduction system. Listen to music in noisy environment ! (Train, Plane, Computer room, ). http://www.technofirst.com/us/casq_lite_us.htm

LITE™: Audio Headphone with Active Noise Reduction system Listen to music in noisy environment (Train, Plane, Computer room,...) The LITE™ headphone benefits from the technology of professional NoiseMaster™ headsets. It provides an attenuation of external noise from 10 to 15 dB in the 20 to 1000 Hz frequency range. Audio input : jack 3.5 mm. Battery : 9 Volts. Box weight : 80 g. Power cable length : 1 m. Headphone sold without CD player ref. : tf-1060 Performances and characteristics

18. First Test Of Fan Active Noise Control (ANC) Completed First Test of Fan active noise control (ANC) Completed. With active noise control (ANC) holds promise as a solution to this problem. It http://www.grc.nasa.gov/WWW/RT1995/2000/2770h.htm

First Test of Fan Active Noise Control (ANC) Completed With the advent of ultrahigh-bypass engines, the space available for passive acoustic treatment is becoming more limited, whereas noise regulations are becoming more stringent. Active noise control (ANC) holds promise as a solution to this problem. It uses secondary (added) noise sources to reduce or eliminate the offending noise radiation. The first active noise control test on the low-speed fan test bed was a General Electric Company system designed to control either the exhaust or inlet fan tone. This system consists of a "ring source," an induct array of error microphones, and a control computer. Fan tone noise propagates in a duct in the form of spinning waves. These waves are detected by the microphone array, and the computer identifies their spinning structure. The computer then controls the "ring source" to generate waves that have the same spinning structure and amplitude, but 180° out of phase with the fan noise. This computer-generated tone cancels the fan tone before it radiates from the duct and is heard in the far field. The "ring source" used in these tests is a cylindrical array of 16 flat-plate acoustic radiators that are driven by thin piezoceramic sheets bonded to their back surfaces. The resulting source can produce spinning waves up to mode 7 at levels high enough to cancel the fan tone. The control software is flexible enough to work on spinning mode orders from -6 to 6. In this test, the fan was configured to produce a tone of order 6.

19. ENGINEERING ANALYSIS INC. ACTIVE NOISE CONTROL ENGINEERING ANALYSIS INC. active noise control. An adaptive filter design based on fractional calculus was developed for active noise control. http://www.mindspring.com/~eai/EAInoise.html

ENGINEERING ANALYSIS INC. ACTIVE NOISE CONTROL The study has involved fractional calculus ANFRAC program was developed. The study demonstrates that an adaptive filter based on fractional calculus for active broad-band noise control is clearly feasible. Welcome Page Background Information Software Customers ... Feedback

20. Experiment active noise control Experiment. With this shareware, you can test and experiment with a very simple active noise control system at home. http://www.val.me.vt.edu/Experiment/experiments.html

Active Noise Control Experiment With this shareware, you can test and experiment with a very simple active noise control system at home. The purpose of this experiment is to demonstrate active noise control. The basic principle of active noise control is to cancel a sound wave (noise) by emitting a secondary opposite (out-of-phase) sound wave (control wave). The active noise control principle is illustrated in the figure below. In the real world, the implementation of active noise control is much more complex due to phase and spatial matching, efficient transducers, system identification, etc., as explained in the paper " Active Control of Sound and Vibration ," by C. R. Fuller and A. H. Flotow. The shareware that you can download, sends a single frequency wave (sine wave at 1000 Hz) to your right speaker. This sound wave represents the noise to be cancelled. By activating the control (pushing on the control button in the program), sound wave of equal amplitude and opposite phase is sent to the left speaker to cancel the noise. Note that for an effective demonstration, the two speakers should face each other and be close to one another (see picture above). If desired, the speakers can then be moved apart and the resulting effect on the sound cancellation observed. This share was tested using "Labtec LCS-800" speakers; the sound cancellation obtained was large and appreciable. Note that the control results depends highly on the quality of speakers used. Please make sure that the volume of each speaker is set to be identical. Also notice that this experiment is more impressive at medium-high volume (please be careful not to overdrive your speakers and ears!).

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

Page 1     1-20 of 91    1  | 2  | 3  | 4  | 5  | Next 20