TY - JOUR
T1 - Pitch synchronous innovation code excited linear prediction (PSI‐CELP)
AU - Miki, Satoshi
AU - Moriya, Takehiro
AU - Mano, Kazunori
AU - Ohmuro, Hitoshi
PY - 1994
Y1 - 1994
N2 - This paper proposes a new speech coding method pitch synchronous innovation code excited linear predictor (PSI‐CELP). This method is based on CELP but adds pitch synchronous innovation. This results in even random codevectors being adaptively converted to have pitch periodicity for voiced frames. This scheme can improve the synthesized speech quality of voiced frames in the low bit‐rate CELP without increasing either computational complexity or bit rate. In addition to pitch synchronous innovation, this paper also proposes four other methods in which the quality of synthesized speech is effectively improved or the computational complexity is reduced for low bit‐rate CELP: (1) the perceptual weighting filter is an MA‐type and uses nonquantized LPC parameters; (2) the fixed codebook is prepared as part of the adaptive codebook for nonperiodic frames; (3) the random codebook consists of two‐channel conjugate sub‐codebooks; and (4) codebook searches are made using delayed decision. In a speech coding system with pitch synchronization of random codevectors, improvements in ratio SNR, segmental SNR, and opinion equivalent Q value are respectively 1.6 dB, 1.0 dB, and 0.5 dB. These basic methods were adopted in the standard codec for Japanese half‐rate digital mobile telephone service.
AB - This paper proposes a new speech coding method pitch synchronous innovation code excited linear predictor (PSI‐CELP). This method is based on CELP but adds pitch synchronous innovation. This results in even random codevectors being adaptively converted to have pitch periodicity for voiced frames. This scheme can improve the synthesized speech quality of voiced frames in the low bit‐rate CELP without increasing either computational complexity or bit rate. In addition to pitch synchronous innovation, this paper also proposes four other methods in which the quality of synthesized speech is effectively improved or the computational complexity is reduced for low bit‐rate CELP: (1) the perceptual weighting filter is an MA‐type and uses nonquantized LPC parameters; (2) the fixed codebook is prepared as part of the adaptive codebook for nonperiodic frames; (3) the random codebook consists of two‐channel conjugate sub‐codebooks; and (4) codebook searches are made using delayed decision. In a speech coding system with pitch synchronization of random codevectors, improvements in ratio SNR, segmental SNR, and opinion equivalent Q value are respectively 1.6 dB, 1.0 dB, and 0.5 dB. These basic methods were adopted in the standard codec for Japanese half‐rate digital mobile telephone service.
KW - CELP
KW - Speech coding
KW - low bit‐rate
KW - mobile telephone
KW - pitch synchronous innovation
KW - random codebook
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U2 - 10.1002/ecjc.4430771204
DO - 10.1002/ecjc.4430771204
M3 - Article
AN - SCOPUS:0028754881
VL - 77
SP - 36
EP - 49
JO - Electronics and Communications in Japan, Part III: Fundamental Electronic Science (English translation of Denshi Tsushin Gakkai Ronbunshi)
JF - Electronics and Communications in Japan, Part III: Fundamental Electronic Science (English translation of Denshi Tsushin Gakkai Ronbunshi)
SN - 1042-0967
IS - 12
ER -