Sökning: "active noise reduction"

Visar resultat 1 - 5 av 26 avhandlingar innehållade orden active noise reduction.

1. 1. Active Noise Control of Enclosed Sound Fields Optimising the Performance

   Författare :Per Sjösten; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; optimising actuator and sensor positions; hybrid controller for anc; fast feedforward algorithm; multiple-error algorithm; active noise control; complex lms; multichannel feedforward algorithm; simulated annealing; mean-field annealing; multiple-reference controller;

   Sammanfattning : Active noise control is the art of reducing a primary unwanted sound field by interference with an actively created secondary sound field. To achieve high reduction, it is crucial to obtain both temporal and spatial matching between the primary and the secondary sound fields. LÄS MER

3. 2. Counteracting Acoustic Disturbances in Human Speech Communication

   Författare :Nils Westerlund; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Speech Enhancement; Noise Reduction; Hearing Aids; Adaptive Feedback Control; Ear-Mic; Active Noise Control;

   Sammanfattning : A signal can be said to be any information bearing unit or action carrying a message from a sender to a receiver. This definition covers a vast number of human and non-human actions, ranging from flirtation to satellite communication. This thesis deals with increasing the quality of one of the most ubiquitous human-to-human signals: Speech. LÄS MER

4. 3. Substrate Noise Coupling in Mixed-Signal Integrated Circuits: Compact Modeling and Grounding Strategies

   Författare :Simon Kristiansson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; active noise reduction; substrate noise coupling modeling; elliptic integrals.; grounding resistance; Mixed-signal integrated circuits; z-parameter; substrate resistance; surface potential;

   Sammanfattning : Integration of digital and analog circuits on the same chip is the result of the microelectronic industry's strive for low-cost, small, hand-held products. However, these mixed-signal circuits can experience interference problems; digital circuits inject noise into the substrate which is transmitted throughout the chip and received by sensitive analog circuits. LÄS MER

5. 4. Vibrations in Metal Cutting : Measurement, Analysis and Reduction

   Författare :Linus Pettersson; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Vibration and noise in metal cutting are ubiquitous problems in the workshop. The turning operation is one kind of metal cutting that exhibits vibration related problems. Today the industry aims at smaller tolerances in surface finish. Harder regulations in terms of the noise levels in the operator environment are also central. LÄS MER

7. 5. Active Vibration Control of Multibody Systems : Application to Automotive Design

   Författare :Claes Olsson; Alexander Medvedev; Stephen Elliott; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Active Vibration Control; Vibration Isolation; Feedback Control; Adaptive Filtering; Saturation; Limit Cycles; Multi Body Systems; Modelling; Simulation; Non-linearity; Gain Scheduling; Structure Flexibility; Automatic control; Reglerteknik;

   Sammanfattning : Active vibration control to reduce vibrations and structure borne noise is considered using a powerful multi-disciplinary virtual design environment which enables control system design to be considered as an integral part of the overall vehicle design. The main application studied is active automotive engine vibration isolation where, first, the potential of large frequency band multi-input multi-output H2 feedback control is considered. LÄS MER