Patent ID: 6219636
Filing Date: 2001-04-17
Classification: G10L

Abstract:
A pitch coding method of calculating and coding a pitch of an input speech, which is divided into a plurality of frames which is further divided into a plurality of sub frames, for each of the sub frames, comprising:a calculating process of calculating a pitch of each of the sub frames included in one or a plurality of the frames;a judging process of judging whether or not the input speech included in each of the sub frames is a voiced sound accompanying a vibration of a vocal chord;a first coding process of (i) coding, if a head sub frame of the sub frames which includes a first input speech is judged to be the voiced sound, the calculated pitch of the head sub frame, and (ii) selecting and coding, if the head sub frame is not judged to be the voiced sound and a subsequent sub frame of the sub frames which is subsequent to the head sub frame is judged to be the voiced sound, one of standard pitch values set in advance for the head sub frame; anda second coding process of (i) calculating and coding, if a preceding sub frame of the sub frames which is preceding to the subsequent sub frame judged to be the voiced sound is judged to be the voiced sound, a difference between the calculated pitch of the preceding sub frame and the calculated pitch of the subsequent sub frame, and (ii) calculating and coding, if the preceding sub frame is not judged to be the voiced sound, a difference between the selected standard value and the calculated pitch of the subsequent sub frame.