Active sound absorber using adaptive signal processing.

Sound Signal Processing Using Complex Dynamic Representation

Abstract : In this paper we show that a complex dynamic representation (logenvelope and instantaneous frequency) can be used efficiently to compress the spectrum and band−shift a discrete−time signal. The original method and algorithm conceived here do not violate the amplitude−phase relationships typical of natural sound signals. This is achieved by simultaneous modification via transmapping o...

Adaptive Piezoelectric Absorber for Active Vibration Control

Abstract: Passive vibration control solutions are often limited to working reliably at one design point. Especially applied to lightweight structures, which tend to have unwanted vibration, active vibration control approaches can outperform passive solutions. To generate dynamic forces in a narrow frequency band, passive single-degree-of-freedom oscillators are frequently used as vibration abso...

Signal Processing for Sound Capture

High-quality electret microphones and single-chip processors are economical enough to be used in large numbers. This latitude opens opportunities for dynamic source location and sound capture with spatial selectivity in three dimensions, This report discusses algorithms for matched-filter processing of microphone arrays and for coordinate tracking of moving talkers. A prototype conferencing sys...

Adaptive Tunable Vibration Absorber using Shape Memory Alloy

This study presents a new approach to control the nonlinear dynamics of an adaptive absorber using shape memory alloy (SMA) element. Shape memory alloys are classified as smart materials that can remember their original shape after deformation. Stress and temperature-induced phase transformations are two typical behaviors of shape memory alloys. Changing the stiffness associated with phase tran...

Adaptive Signal Processing