BASIC ALGORITHM OF PITCH SYNCHRONOUS INNOVATION CELP (PSI-CELP) SPEECH CODING

This paper proposes a new speech coding method called PSI-CELP (Pitch Synchronous Innovation CELP). This method is based on CELP, but adds p itch synchronous innovation, which means that even random codevectors are adaptively converted to have pitch periodicity for voiced frames. In addition, this paper also proposes four other methods: (a) a fixed codebook that is prepared as part of the adapative codebook for nonper iodic frames, (b) a random codebook which consists of two conjugate su b-codebooks, (c) an MA-type perceptual weighting filter using unquanti zed LPC parameters, and (d) codebook searches using delayed decision. PSI-CELP improves the SNR, segmental SNR, and opinion equivalent Q val ue of the coding system by 1.6 dB, 1.0 dB, and 0.5 dB respectively.