Hiroyoshi Morikawa was bom in Japan on February 7, 1949 . He received the BS degree in management engineering from Osaka Electrocommunications University in 1971, and the MS degree in radiocommunications from University of Electrocommunications, Tokyo, in 1973 Tokyo, Tokyo, Japon, in 1954, 1956, and 1962, respectively. In 1962, he joined the Faculty of Engineering of the University of Tokyo as Assistant Professor . He has held the position of Professor of Electronic Engineering since 1973 . He has been engaged research on speech communication and information processing and published a number of technical papers and several books . Dr. Fujisaki is Vice-President of the Acoustical Society of Japan . He has been Chairman of the Tokyo Chapter of the IEEE Acoustics, Speech, and Signal Processing Society . He is a fellow of the Acoustical Society of America, and a member of the Institute of Electronics, Information and Communication Engineers of Japan, the Information Processing Society of Japon, the Linguistic Society of Japon, Tau Beta Pi, and Sigma Xi . SUMMARY A modified SEARMA method is proposed for estimating the speech spectrum in the presence of colored background noise . The following assumptions are used in developing the analysis . The speech production process is represented by an autoregressive moving-average (ARMA) mode] . The background noise is represented by an MA process . The noise process is locally stationary during speech activity. Following these assumptions, the process during speech activity can be represented by an extended ARMA model . In this formulation, unique estimation of AR parameters of the vocal tract transfer function is always possible if the MA parameters of the noise process can be estimated separately, but the estimation of MA parameters of the speech production process requires further assumption of a high SNR . The validity of the proposed method is demonstrated by spectral estimation of both synthetic and natural speech sounds in the presence of additive colored noise, and by comparing the results with those obtained by the LPC method .
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