• 한국음향학회지
• /
• 제26권1호
• /
• pp.8-15
• /
• 2007

음향 공동-유리창 연성계를 대상으로 도청음의 음성 명료도를 검토한다. MLS신호를 음원으로 유리창의 가속도와 속도 응답을 가속도계와 레이저 도플러 진동계를 사용하여 측정한다. 변조전송함수 (MTF)를 사용하여 공동-유리창 진동계의 음성전달특성을 규명한다. 변조전송함수에 근거하여 음성전송지수 (STI)를 구하고, 유리창 진동음의 음성명료도를 평가한다. 가속도음과 속도음의 음성명료도를 비교하고, 최종적으로 대화음의 명료도를 주관적 평가로 확인한다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 추계학술대회논문집
• /
• pp.150-155
• /
• 2006

Speech intelligibility is investigated on a conference room-window glass coupled system. Using MLS(Maximum Length Sequency) signal as a sound source, acceleration and velocity responses of the window glass are measured by accelerometer and laser doppler vibrometer. MTF(Modulation Transfer Function) is used to identify the speech transmission characteristics of the room and window system. STI(Speech Transmission Index) is calculated by using MTF and speech intelligibility of the room and the window glass is estimated. Speech intelligibilities by the acceleration signal and the velocity signal are compared and the possibility of the wiretapping is investigated. Finally, intelligibility of the conversation sound is examined by the subjective test.

• 산업기술연구
• /
• 제27권A호
• /
• pp.55-60
• /
• 2007

Possibility of the eavesdropping is investigated on a conference room-glass window coupled system. Speech intelligibility analysis is performed on the eavesdropping sound of the glass window. Using MLS(Maximum Length Sequency) signal as a sound source, acceleration and velocity responses of the glass window are measured by accelerometer and laser doppler vibrometer. MTF(Modulation Transfer Function) is used to identify the speech transmission characteristics of the room and window system. STI(Speech Transmission Index) is calculated by using MTF and speech intelligibility of the vibration sound is estimated. Speech intelligibilities by the acceleration signal and the velocity signal are compared.

• 한국음향학회지
• /
• 제28권2호
• /
• pp.127-134
• /
• 2009

본 연구에서는 다양한 두께의 유리창을 대상으로 레이저 원격 도청 가능성을 검토한다. MLS 신호음을 사용하여 유리창을 진동시키고 레이저 도플러센서로 진동음을 탐지한다. 탐지된 진동음으로부터 음성정보의 인식 수준인 음성명료도를 객관적으로 평가한다. 평가에는 변조전송함수에 근거하여 결정되는 음성전송지수를 사용한다. 또한, 외부 스피커와 유리창 교란기로 각각 교란파를 발생시켜, 배경소음과 도청방지기의 음성명료도에 대한 교란효과를 평가한다. 다양한 두께의 유리창을 대상으로 레이저 원격 도청음의 음성인식 수준과 국산 도청 방지장치의 도청방지 성능을 평가하는 데에 본 연구의 목적이 있다.

• 한국소음진동공학회논문집
• /
• 제17권4호
• /
• pp.363-369
• /
• 2007

The purpose of the study is to obtain acoustical information to prevent eavesdropping of the glass window. Speech intelligibility was investigated on the vibration sound detected from the glass window of a conference room. Objective test using speech transmission index(STI) was performed to estimate quantitatively the speech intelligibility. STI was determined based on tile modulation transfer function(MTF) of the room-glass window system. Using Maximum Length Sequency(MLS) signal as a sound source, impulse responses of the glass window and MTF were determined by signals from accelerometers and laser doppler vibrometer. Finally, speech intelligibility of the interior sound and window vibration were compared under different sound pressure levels and amplifier gains to confirm the effect of measurement condition on the speech intelligibility.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 춘계학술대회논문집
• /
• pp.649-654
• /
• 2007

Eavesdropping prevention performance is evaluated on a commercial window shaker, which is used to prevent a glass window from eavesdropping. Speech transmission index (STI) is introduced in order to estimate quantitatively the speech intelligibility of the sound detected on the glass window. Objective test by IEC standard using modulation transfer function (MTF) is performed to determine STI. Using Maximum Length Sequency (MLS) signal as a sound source, MTF is measured by accelerometers and laser doppler vibrometer. STI under different level of disturbing wave are compared to confirm the disturbing effect on the speech intelligibility.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 춘계학술대회논문집
• /
• pp.551-556
• /
• 2008

Possibility of the remote eavesdropping through window glass is investigated using a laser sensor. Various thicknesses and types of glass windows are excited by maximum length sequency (MLS) signal and the vibration sound is detected by a laser doppler vibrometer. Intelligibility of the detected sound is evaluated using the speech transmission index (STI), which is based on the modulation transfer function (MTF). In order to identify the disturbing effect, different level of disturbing wave is generated by an outside speaker and a window shaker attached on the glass window. On the different thickness of glass windows, decrease effect of the speech intelligibility is analysed.

• 한국소음진동공학회논문집
• /
• 제15권3호
• /
• pp.320-328
• /
• 2005

Last target of architectural acoustics is that people wish to convey voice effectively from the space adaptively in use purpose in building. But, how exactly through space sound (sound source) that wish to deliver from indoor can be passed method to do quantification and evaluate quantity of sound by method to serve indoor architectural acoustics estimation summer period and methods to estimate definition propose. This Study searches special quality of sound source about MLS signal that is occurred short-answer sound source (pistol sound source) and nondirectional speaker among indoor sound estimation method, and measure and analyzed reverberation time (RT60), definition (C80, D50) by regulation of each ISO 3382 in age place (classroom, hall, gymnasium). Analysis result and sound factor among could know that d of two sound sources converges in measurement error extent about reverberation time (RT60) of analysis incidental and sound factors and value shows change irregularly about sound factor of D50, C80, pistol sound source judged there is problem. Also, could know that problem is happened in deflection except reverberation time is in deflection analysis with wave that measure each in fixed distance in branch. Finally, when differ size of sound source and measure about change of sound pressure level in case measure sound pressure level giving difference about 10 dB, sound factor could know that there is no different effect.