Realization and applications of highly directional acoustic system

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05857
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Dynamics/Control
• Research Institution: The University of Electro-Communications
• Principal Investigator: Kamakura Tomoo 電気通信大学, 産学官連携センター, 客員教授 (50109279)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 超音波 / 非線形音響 / パラメトリックスピーカ / ハイレゾリューション

Outline of Final Research Achievements

This study introduces theoretical and experimental attempts for the improvement of conversion efficiency from electric to acoustic power in driving parametric loudspeakers. In line with the fact that parametric sound pressure is generally increased by decreasing primary frequencies, a 25-kHz ultrasonic emitter is fabricated in order to realize a long distance acoustic alert system. Incidentally, audio signals pass through three processes when parametric loudspeaker is driven. These are the amplitude-modulation process, emitting process of ultrasound waves, and self-demodulation process. To find clues to improve the features of parametric loudspeaker, the study demonstrates that the above three processes are mathematically modeled and are successfully connected via computer simulation of using high resolution source signals with 96 kHz sampling frequency and 16-bit quantization.

Free Research Field

音響エレクトロニクス