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Analysis of Frequency Response Characteristics in Optical Microphone

광 마이크로폰의 주파수 응답특성 분석

  • 염경태 (원광대학교 전기전자 및 정보공학부) ;
  • 김관규 (원광대학교 전기전자 및 정보공학부) ;
  • 허도근 (원광대학교 전기전자 및 정보공학부) ;
  • 김용갑 (원광대학교 전기전자 및 정보공학부)
  • Published : 2008.06.28

Abstract

In this paper, in order to analyze property of frequency response in optical microphone, system was implemented. The capacitance microphone and fiber-optic transmission path type fiber-optic microphone (FOM) have weaknesses in directivity, size, weight, and price. However suggested optical microphone can be constituted by cheap devices, so it has many benefits like small size, light weight, high directivity, etc. Head part of optical microphone which is suggested in this paper is movable back and forth by sound pressure with the attached reflection plate. Operating point is determined by measuring the respond characteristics and choosing the point on which has maximum linearity and sensitivity while changing the distance between optical head and vibrating plate. We measured the output of the O/E transformed signal of the optical microphone while frequency of sound signal is changed using sound measurement/analysis program, Smaart Live and USBPre, which are based on PC, and compared the result from an existing capacitance microphone. The measured Optical microphone showed almost similar output characteristics as those of the compared condenser microphone, and its bandwidth performance was about 300[Hz]-3[kHz] at up to 3 [dB].

Keywords

Optical Sensor;Microphone;Diaphragm;Acousto-Optic Sensor;Transducer

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