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대칭구조를 갖는 일반적인 고차의 미분 에너지함수를 기반한 순간주파수를 이용한 음성의 기본주파수 추정
임병관(Byeong Gwan Iem) 대한전기학회 2011 전기학회논문지 Vol.60 No.12
The fundamental frequency of the voiced speech is estimated using the instantaneous frequency based on the symmetric higher order differential energy operator. The instantaneous frequency based on the symmetric higher order energy operator shows better frequency estimation result since it is aligned to the time instance of the signal. The speech is pre-processed by a lowpass filter to remove higher frequency components. Then, it is processed by the instantaneous frequency to obtain the fundamental frequency estimates. The symmetric higher order energy operator has been used as an indicator to determine the voiced/unvoiced speech. The fundamental frequency estimates are further processed by a moving average filter to obtain the monotonically changed estimates. The obtained fundamental frequency estimates have been compared with the spectrogram of the speech to confirm its accuracy.
자연스런 인간-로봇 상호작용을 위한 음성 신호의 AM-FM 성분 분해 및 순간 주파수와 순간 진폭의 추정에 관한 연구
이희영,Lee, He-Young 한국음성학회 2005 음성과학 Vol.12 No.4
A Vowel of speech signals are multicomponent signals composed of AM-FM components whose instantaneous frequency and instantaneous amplitude are time-varying. The changes of emotion states cause the variation of the instantaneous frequencies and the instantaneous amplitudes of AM-FM components. Therefore, it is important to estimate exactly the instantaneous frequencies and the instantaneous amplitudes of AM-FM components for the extraction of key information representing emotion states and changes in speech signals. In tills paper, firstly a method decomposing speech signals into AM - FM components is addressed. Secondly, the fundamental frequency of vowel sound is estimated by the simple method based on the spectrogram. The estimate of the fundamental frequency is used for decomposing speech signals into AM-FM components. Thirdly, an estimation method is suggested for separation of the instantaneous frequencies and the instantaneous amplitudes of the decomposed AM - FM components, based on Hilbert transform and the demodulation property of the extended Fourier transform. The estimates of the instantaneous frequencies and the instantaneous amplitudes can be used for modification of the spectral distribution and smooth connection of two words in the speech synthesis systems based on a corpus.
Seun Jin Chang,Yoon Ho Choi,Yong June Shin,Jin Bae Park 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10
In this paper, an impedance discontinuities localization for the nuclear control cable using the time-frequency domain reflectometry (TFDR) is proposed. By analyzing characteristics of the target cable, the reference signal is designed. To be prepared for on-voltage experiment, the reference signal is injected into the target cable via capacitive coupler. Using the Wigner distribution, the reflected signal from the impedance discontinuities is analyzed in time-frequency domain. To estimate instantaneous frequency (IF) of the signal, the Wigner-Hough Transform(WHT) is applied to the nuclear cable. Through the estimating time delay between the IF of the reference signal and that of the reflected signal, the impedance discontinuities localization can be measured. The experiment using the TFDR is carried out to localize the impedance discontinuities spot as the end of target cable. Through the experiment, the performance of the proposed TFDR system is verified.
전파 거리에 따른 신호의 감쇠와 분산이 고려된 순시 주파수 추정 알고리즘 및 장거리 전파용 반사파 계측법 시뮬레이터 개발
성현모(Hyun-Mo Seong),심연섭(Yeon-Sub Sim),장승진(Seung Jin Chang) 대한전기학회 2023 전기학회논문지 Vol.72 No.6
Time-Frequency domain Reflectometry(TFDR) is used for the purpose of fault detection and evaluating the integrity in cables. TFDR can diagnose live wire in nondestructive. but, the incident signal cannot aviod attenuation and dispersion according to increasing propagation distance, propagation velocity changes with propagation distance. attenuation and dispersion in long distance lead to decresing falut detection performance of cable. therefore, Developing instantaneous frequency Estimation algorithm of signal and signal restoration algorithm in order to determine tendency of propagation velocity for propagation distance, we demonstrate the performance of algorithm by implementing TFDR simulator possible long length.