서지주요정보
과도 음향 신호의 음질 해석 = Sound quality analysis of nonstationary acoustic signals
서명 / 저자 과도 음향 신호의 음질 해석 = Sound quality analysis of nonstationary acoustic signals / 정혁.
저자명 정혁 ; Jeong, Hyuk
발행사항 [대전 : 한국과학기술원, 1999].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8010318

소장위치/청구기호

학술문화관(문화관) 보존서고

DME 99041

휴대폰 전송

도서상태

이용가능

대출가능

반납예정일

초록정보

For the noise control of commercial products, the most important fact is the subjective feeling of the human being on noise and the countermeasure plans should be properly prepared for reducing the annoyance due to the noise source. It is recently known that sound quality metrics are more useful for describing the subjective preference of product sounds than the strength related metrics. Example metrics of the former include loudness, sharpness, roughness and fluctuation strength and the latter includes the overall sound pressure level expressed in the A-weighted decibels. As a result of psychoacoustic research, models of sound quality metrics have been developed that allow for prediction and evaluation of attributes of hearing events. However, signal-processing techniques for the analysis of unsteady sounds in these models have been not clearly given yet. In this study, models of sound quality metrics for unsteady sounds are generated and the signal-processing techniques appropriate for this purpose are introduced such as digital filtering and time-frequency analysis. Based on Zwicker's loudness model for steady sounds, the loudness model for unsteady sounds is suggested. For dealing with nonstationary acoustic signals, the suggested loudness model contain the signal processing technique such as bandpass filtering and envelope extraction and simulation algorithms of psychoacoustic facts such as post-masking and temporal integration. In the proposed roughness model, the analysis method based on the Fourier transform for overlapped 47 critical bands is used and details of each step such as calculation of excitation and correlation coefficient are discussed. The proposed roughness model is in turn used for modeling the fluctuation strength. In modeling the fluctuation strength, several weighting functions complying with the psychoacoustic experimental results are employed. The usefulness of suggested models is confirmed by comparing the calculation results of present model with psychoacoustic facts. Additionally, previous models are revised to improve the calculation accuracy of the present models and to make easy for searching the mainly contributing frequency components to the sound quality of a product. For example, in the revised loudness model, overlapped 47 critical bandpass filters instead of conventional 24 filters are used especially for minimizing the loudness error of frequency-varying pure tones within the same critical band. In addition, a signal processing technique is proposed for the time-frequency analysis of the unsteady sound signals considering the auditory perception model, which is called the VFR-STFT (Short Time Fourier Transform with Variable Frequency Resolution). The conventional STFT, which is commonly used for the spectral analysis of unsteady sounds, is not suitable for the auditory model because the frequency resolution of the spectral analysis within the hearing system is not constant but varies with frequencies. In this study, the frequency resolution of the VFR-STFT can be adjusted to the variation of analyzed frequency ranges by introducing the downsampling technique. In the implementation of the VFR-STFT, calculation schemes are included for minimizing the undesirable effects: the distortion of overall level due to non-overlapping of the analysis windows and the impairment of partial spectra due to the finite order of anti-aliasing filters. Additionally, a procedure for equalizing time grids at all frequency ranges is included in order to describe the two-dimensional time-frequency map having different time grids. The proposed VFR-STFT is applied to the spectral analysis of the extraction of tonal components in an unsteady sound. The results are compared with those from other time-frequency analysis methods such as STFT, VFR-FFT (Fast Fourier Transform with Variable Frequency Resolution) and wavelet packet method. It is found that the proposed VFR-STFT algorithm describes the auditory sensation of time-varying and intermittent tones very excellently as well as steady sounds.

서지기타정보

서지기타정보
청구기호 {DME 99041
형태사항 xiii, 135 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Hyuk Jeong
지도교수의 한글표기 : 이정권
지도교수의 영문표기 : Jeong-Guon Ih
수록잡지명 : "Implementation of the New Algorithm Using the STFT with Variable FrequencyResolution for the Time-Frequency Auditory Model". Journal of Audio Engineering Society, vol 47, no.4, pp. 240-251 (1999)
학위논문 학위논문(박사) - 한국과학기술원 : 기계공학과,
서지주기 참고문헌 : p. 132-135
주제 음질
심리음향학
라우드니스
러프니스
Sound quality
Psychoacoustics
Loudness
Roughness
VFR-STFT
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