• Title/Summary/Keyword: Sound signal

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Tonality Design for Sound Quality Evaluation for Gear Whine Sound (승합차량의 액슬기어 음질의 평가를 위한 새로운 순음도 모델 개발과 응용)

  • Kim, Eui-Youl;Jang, Ji-Uk;Lee, Sang-Kwon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.12
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    • pp.1172-1183
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    • 2012
  • Aure's tonality was considered as the sound metrics for the expression of the tonality of gear whine sound in a previous research. It was failed to use the Aure's tonality as a sound metric for the tonal impression. Thus Aures's tonality, was developed for tonal impression in previous research. However, this metric did not express well the tonality of gear whine sound since the whine sound is a non-stationary signal with frequency modulation and amplitude modulation. In this study, the new method for the tonality evaluation for a non-stationary signal is presented. It is developed based on the prominence ratio, tonality impression function, and lower threshold level. It improves the accuracy and reliability of the sound quality index being used for the sound quality evaluation of the axle-gear whine sound.

Improving The Excitation Signal for Low-rate CELP Speech Coding (저전송속도 CELP 부호화기에서 여기신호의 개선)

  • 권철홍
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1998.08a
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    • pp.136-141
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    • 1998
  • In order to enhance the performance of a CELP coder at low bit rates, it would be necessary to make the CELP excitation have the peaky pulse characteristic. In this paper we introduce an excitation signal with peaky pulse characteristic. It is obtained by using a two-tap pitch predictor. Samples of the signal have different gains according to their amplitudes by the predictor. In voiced sound the signal has the desirable peaky pulse characteristic, and its periodicity is well reproduced. Particularly, peaky pulses at voiced onset and a burst of plosive sound are clearly reconstructed.

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Order Tracking without a Tacho Signal - A new Method and Its Applicability for Rotating Machinery Diagnostics

  • Pedersen, Thorkiid Find;Konstantin-Hansenf, Hans
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.271-274
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    • 2005
  • For noise and vibration order-analysis on rotating machinery, it is compulsory to measure the RPM of the rotating part of the machine. Normally the RPM is measured using dedicated tacho-probes. In this paper we describe a new method that in real-time synthesizes a tacho signal from the measured noise or vibration signal thus eliminating the tacho probe. The method strengths and weaknesses are evaluated on practical signals.

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Analysis of Reference Signal for Immunity Test of Sound System and Television Broadcast Receiver (음향 기기 및 TV 방송 수신기의 내성 시험용 기준 신호 분석)

  • Choi, Su-Na;Cho, Sung-Woong;Park, Seung-Keun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.7
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    • pp.805-814
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    • 2012
  • Intermittent or periodic signals with undulating amplitudes of mobile devices cause interference noise at audible frequency to the sound system which is installed nearby. In this regard, it is recently issued that the intermittently transmissions of LTE mobile phones cause the interference noises with sound systems, similar to that of GSM mobile phones. For retaining the immunity to noises, a national regulation KN20 suggests a 1 kHz AM 80 % and a CDMA modulation signal as reference signals for immunity test of sound and television broadcast receiver. In this paper, the effects of interference noises of AM and CDMA are compared with those of GSM and LTE, and the improvement of reference signal for national immunity test of sound systems is suggested. It is recommended to delete the CDMA modulation signal from reference signals for immunity test because it hardly cause interference noise with sound systems. On the other hand, it is desirable to select the modulation signal of LTE instead of CDMA as a reference signal for immunity test of sound system and television broadcast receiver because many people use the LTE service and it is analysed that the LTE signal causes considerable interference noises.

A study on digital sound reception systems for ships (선박용 디지털 음향수신장치 연구)

  • Kim, Hyungjong;Kim, Jeongchang
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.9
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    • pp.1125-1130
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    • 2014
  • In this paper, we propose a sound reception system against surrounding noise for ships based on digital signal processing technologies. In order to suppress unwanted surrounding noises, a digital band-pass filter is designed, which the pass-band of the filter is between 70Hz to 820Hz. Also, we develope a sound direction indicating algorithm with 4 microphones. After filtering the audio signals from 4 microphones, the developed sound direction indicating algorithm can indicate 8 directions. In addition, we implement prototype board for the sound reception using a digital signal processor chip and audio codecs, and verify the proposed algorithm.

Perception of sentences varying with prosody pattern, sound intensity, and signal-to-noise ratio (운율 패턴, 강도, 신호대소음비에 따른 문장 지각 변화)

  • Chang, Son-A;Jang, Eunjoo;Jang, Jaejin
    • Phonetics and Speech Sciences
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    • v.9 no.2
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    • pp.119-124
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    • 2017
  • This study investigates how perception of easy sentences varies with prosody pattern, sound intensity, and signal-to-noise ratio(SNR) in young adults with normal hearing who were in their 20's. The results showed that the presence of proper prosody pattern in the sentences increased correct perception rate of the target sentences, and that the lower the intensity and SNR, the lower the sentence perception scores. The results also showed that SNR had a greater effect on the sentence perception scores than sound intensity. There was a significant decrease of perception scores starting at the level of 15 dB and +3 SNR for the sentences with prosody pattern, while starting at the level of 18 dB and +6 SNR for the sentences without prosody pattern, ending up with a very poor perception score as sound intensity and SNR gets lower. There was a significant difference in the perception score of the sentences with prosody pattern between 20 year-old group and 21 year or older group in several listening conditions of sound intensity and SNR.

Intelligibility Analysis on the Eavesdropping Sound of Glass Windows Using MTF-STI (MTF-STI를 이용한 유리창 도청음의 명료도 분석)

  • Kim, Hee-Dong;Kim, Yoon-Ho;Kim, Seock-Hyun
    • The Journal of the Acoustical Society of Korea
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    • v.26 no.1
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    • pp.8-15
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    • 2007
  • Speech intelligibility of the eavesdropping sound is investigated on a acoustic cavity - glass window coupled system. 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 tile speech transmission characteristics of the cavity and window system. STI (Speech Transmission Index) based upon MTF is calculated and speech intelligibility of the vibration sound of the glass window is estimated. Speech intelligibilities by the acceleration signal and the velocity signal are compared. Finally, intelligibility of the conversation sound is confirmed by the subjective test.

Speech Intelligibility Analysis on the Vibration Sound of the Window Glass of a Conference Room (회의실 유리창 진동음의 명료도 분석)

  • Kim, Yoon-Ho;Kim, Hee-Dong;Kim, Seock-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.150-155
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    • 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.

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A Study on the Eavesdropping of the Glass Window Vibration in a Conference Room (회의실내 유리창 진동의 도청에 대한 연구)

  • Kim, Seock-Hyun;Kim, Yoon-Ho;Heo, Wook
    • Journal of Industrial Technology
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    • v.27 no.A
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    • pp.55-60
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    • 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.

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A Study on 2-Dimensional Sound Source Tracking System II (2차원적 음원추적에 관한 연구 II)

  • 문성배;전승환
    • Journal of the Korean Institute of Navigation
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    • v.22 no.4
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    • pp.31-36
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    • 1998
  • The whistle is a very important information source for the safety navigation under foggy weather. But navigator has no concern about this, because it must be achived by human hearing sense and considered as a vague signal. If the range and relative bearing of signal source can be detected automatically, it would be very useful system for preventing marine casualties making a lot of economic loss and environment pollution. Before the algorithm of 2-dimensional sound source tracking system was reported. This paper describes the method that can obtain the time lag between three signals and the theory of cross-correlation analysis and subtraction method for cauculating the time lag by using the digital signal data sequences. And a series of experiments were carried out for various position of sound source in the range from 200cm to 530cm. As a result, we have recognized that sound source tracking system is possible to the sea field with improvement of position error.

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