Radiation mode-based microphone array: Experimental verification.

The mouth of a speaker is generally close to the microphones of speech communication devices, such as headsets and phones, whereas noise sources are more distant from the microphones. Hence, near-field enhancement using microphone arrays is a promising strategy for noise suppression. This study deals with radiation mode-based microphone arrays and mainly focuses on experimentally validating the methodology.

Microphone array based on tangent line method.

The tangent line method (TLM) was originally proposed for loudspeaker arrays to generate curvilinear acoustic beams. In this study, the TLM was applied to a microphone array. Based on reciprocity, the TLM-based microphone array can be used to form curvilinear beams.

Sound delivery to listening point using tangent line method.

In personal audio systems, sounds should propagate toward the listening point and attenuate beyond the listening point. This study deals with controlling directivity and distance attenuation using loudspeaker arrays. The array signal processing is based on tangent line method (TLM), which can generate acoustic beams following arbitrary convex trajectories.

Generalized radiation modes and microphone arrays for close-talking.

In close-talking applications, such as mobile phones, selective measurement of the near-field sound is desirable as it can be used to improve the signal-to-noise ratio. In this study, the theory of generalized radiation modes is applied to the design of microphone arrays. The generalized radiation modes are formulated as a generalized eigenvalue problem related to the specific acoustic impedances on the array surface.

Controlling a distance from linear loudspeaker arrays to a listening point by using tangent line method.

A technique for confining the acoustic fields near loudspeaker arrays is proposed for personal audio systems. The proposed technique is based on tangent line method (TLM), which enables the production of circular acoustic beams. The produced beams are focused at a point designated as the listening point.

Radiation modes and acoustic field confined near acoustic sources.

A method to confine the acoustic pressure distribution near a loudspeaker array is investigated for potential application to personal audio devices. The surface velocity distribution of the loudspeaker array is determined so that more reactive than active acoustic power can be generated. The design is based on the theory of radiation modes, i.

Design Procedure and Experimental Verification of a Broadband Quad-Stable 2-DOF Vibration Energy Harvester.

Vibration-based energy harvesters brought the idea of self-powered sensors to reality in the past few years. Many strategies to improve the performance of linear vibration energy harvesters that collect energy over a limited bandwidth have been proposed. In this paper, a bi-stable two degrees of freedom (2-DOF) cut-out vibration energy harvester employing a pair of permanent magnets is designed through a proposed design methodology.

Radiation clusters and the active control of sound transmission into a symmetric enclosure.

Radiation cluster control is proposed for the purpose of attenuating harmonic sound transmission into a symmetric enclosure using error signals derived from structural vibration sensors. The approach falls into a category of middle authority control, which is between LAC (low authority control: structural modal control) and HAC (high authority control: radiation modal control), possessing the benefit of practicality over LAC, while providing high control performance and some flexibility of control gain assignment similar to HAC. The structure of a radiation cluster control system is outlined, showing that it is possible to control a target cluster without affecting the other clusters.