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Development of Higly Directive Sound Gidance System for Safe Walking

Research Project

Project/Area Number 17310096
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Social systems engineering/Safety system
Research InstitutionThe University of Electro-Communications

Principal Investigator

KAMAKURA Tomoo  The University of Electro-Communications, Faculty of Electro-Communications, Professor, 電気通信学部, 教授 (50109279)

Co-Investigator(Kenkyū-buntansha) NISHI Kazuki  The University of Electro-Communications, Faculty of Electro-Communications, Associate Professor, 電気通信学部, 助教授 (00208125)
AOKI Kenichi  The University of Electro-Communications, Faculty of Electro-Communications, Research Assistant, 電気通信学部, 助手 (30017412)
TOI Takeshi  Chuo University, Faculty of Science and Engineering, Professor, 理工学部, 教授 (90286956)
鈴木 英男  千葉工業大学, 情報科学部, 教授 (50333018)
Project Period (FY) 2005 – 2006
Project Status Completed (Fiscal Year 2006)
Budget Amount *help
¥10,100,000 (Direct Cost: ¥10,100,000)
Fiscal Year 2006: ¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 2005: ¥5,300,000 (Direct Cost: ¥5,300,000)
KeywordsParametric loudspeaker / Weaver SSB modulator / Digital power amplifier / Pedestrian signal / 音環境 / SSB / ウエーバー(Weaver)方式 / D級アンプ
Research Abstract

A highly directional loudspeaker like a spotlight is actually realized by the self-demodulation effect of an intense airborne ultrasound amplitude-modulated by audio signals. This loudspeaker, which is usually called a parametric loudspeaker in acoustics, is based on the generation of a parametric array (in addition, virtual and end-fire array) in the beam space, and is able to transmit faithfully audio sounds to a specific area that cannot be detected by people in adjacent locations. The most remarkable and interesting property of the difference frequency component or parametric array is its sharp directivity that cannot be realized by any conventional loudspeakers with the same aperture size. Additionally, the side-lobes that usually exist for a directive sound source are suppressed considerably. According to our previous research on a parametric loudspeaker, three problems remain unsolved for practical applications. The problems are summarized as follows. First, to reduce harmonic d … More istortion in parametric sounds as much as possible, appropriate signal processing is needed in driving the parametric loudspeaker. Under the financial supports from the Grants-in-Aid for Scientific Research, we, in collaboration with Mitsubishi Electric Engineering Company, have worked during two years to reduce the distortion by means of a suitable modulation of the carrier intense ultrasound. The method is based on a single-side band (SSB) modulation with the carrier whose amplitude is dynamically changed in proportional to an input audio signal. This dynamic SSB modulation then achieves less distortion as well as less electric power consumption in working the parametric loudspeaker. The modulator is realized through digital circuit technology so as to adjust its modulation functions accurately and readily. Second, to reduce electric power consumption, they are now developing a digital power amplifier to drive the loudspeaker with power saving. We confirm that our preliminary experiments using a digital power amplifier demonstrate that the power consumption is reduced more than 75 % incomparison with a analog power amplifier. This technology is also of importance for further developing the parametric loudspeaker. Finally, we have to develop an airborne ultrasonic transducer that radiates an intense and a relatively wide-band carrier wave. Additionally, the transducer requires high conversion efficiency from electric power to ultrasonic power and robustness in mechanics. The last problem is a next step for research project, and would be overcome by new technology such as MEMS, thus creating better products with good sound and electric performances. Less

Report

(3 results)
  • 2006 Annual Research Report   Final Research Report Summary
  • 2005 Annual Research Report
  • Research Products

    (12 results)

All 2006

All Journal Article (11 results) Patent(Industrial Property Rights) (1 results)

  • [Journal Article] パラメトリックスピーカの実用化2006

    • Author(s)
      鎌倉友男, 酒井新一
    • Journal Title

      日本音響学会誌 62巻11号

      Pages: 791-797

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] A highly directional audio system using a parametric array in air (invited paper)2006

    • Author(s)
      T.Kamakura, K.Aoki, S.Sakai
    • Journal Title

      9th WESPAC in Seoul (June, 2006).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Study of sound radiation mechanism for an airborne ultrasonic transducer2006

    • Author(s)
      S.Sakai, K.Yasutake, T.Toi, Y.Shiozawa, T.Kamakura
    • Journal Title

      9th WESPAC in Seoul (June, 2006).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Principle and applications of a parametric loudspeaker (Invited paper)2006

    • Author(s)
      T.Kamakura, S.Sakai
    • Journal Title

      IEICE Technical Report US2005-116

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Study on optimum arrangement of ultrasonic transducers for parametric loudspeaker2006

    • Author(s)
      S.Sakai, K Yasutake, T.Kamakura
    • Journal Title

      IEICE Technical Report US2006-81

    • NAID

      110005717018

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Practical development of a parametric loudspeaker2006

    • Author(s)
      T.Kamakura, S.Sakai
    • Journal Title

      J.Acoust.Soc.Jp. 62

      Pages: 791-797

    • NAID

      110004837178

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] A highly directional audio system using a parametric array in air (invited paper)2006

    • Author(s)
      T.Kamakura, K.Aoki, S.Sakai
    • Journal Title

      9th WESPAC in Seoul

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Study of sound radiation mechanism for an airborne ultrasonic transducer2006

    • Author(s)
      S.Sakai, K.Yasutake, T.Toi, Y.Shiozawa, T.Kamakura
    • Journal Title

      9th WESPAC in Seoul

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Principle and applications of a parametric loudspeaker (Invited paper)2006

    • Author(s)
      T.Kamakura, S.Sakai
    • Journal Title

      IEICE Technical Report US

      Pages: 2005-2116

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Study on optimum arrangement of ultrasonic transducers for parametric loudspeaker2006

    • Author(s)
      S.Sakai, K Yasutake, T.Kamakura
    • Journal Title

      IEICE Technical Report US

      Pages: 2006-2081

    • NAID

      110005717018

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] パラメトリックスピーカの実用化2006

    • Author(s)
      鎌倉友男, 酒井新一
    • Journal Title

      日本音響学会 62巻11号

      Pages: 791-797

    • Related Report
      2006 Annual Research Report
  • [Patent(Industrial Property Rights)] 変調器及び超指向性音響装置2006

    • Inventor(s)
      鎌倉友男, 酒井新一, 吉田俊治
    • Industrial Property Number
      2006-192997
    • Filing Date
      2006-07-13
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Annual Research Report 2006 Final Research Report Summary

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Published: 2005-04-01   Modified: 2016-04-21  

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