The Preliminary Report on the Cognitive Superiority of Phase Error to Amplitude Envelope in Speech : A MMN Study

抄録

It has been reported that the maximum and minimum data of the narrow-band (one octave) acoustic waveforms played a key role in the speech synthesis by using the sinusoidal interpolation between two successive extrema. Although two indices of phase and quantization errors of the extrema have closely related to the perception of sound localization, and the form of amplitude envelope, respectively, which has been regarded as a principal carrier of speech waveforms, the interaction between the two has remained unclear as to which is a critical factor in the auditory cognitive system in the previous study. We have, then, measured the mismatch negativity (MMN) of the event-related potentials, by using a repetitive stimulus of a male syallable /kal, randomly replaced at a 14.3 % probability by the synthesis. Salient MMN component has been elicited by the synthesized syllable with 7 % phase error, but not the corresponding one with quantization error. It has been suggested that the two key indices concerning the quality of sound demonstrated the intrinsic features of the cognitive system with superior temporal resolution but inferior sensitivity to noise in amplitude envelope.