| 摘要 |
PROBLEM TO BE SOLVED: To provide a speech communication system and method which are improved for handling information lost during transmission from the encoder to the decoder. SOLUTION: In the improved speech communication system, the minimum spacing between LSFs is set to an increased value, and then the value for subsequent frames is decreased in a controlled adaptive manner in order to handle the lost LSFs. Moreover, the system estimates a lost pitch lag by extrapolating from the pitch lags of a plurality of the preceding received frames in order to handle lost pitch lags. Furthermore, when the decoder receives the pitch lag of the succeeding frame, the system finely adjusts its estimation of the pitch lag for the lost frame, by using a curve fitting between the pitch lag of preceding received frame and the pitch lag of the succeeding received frame, and adjusts or corrects the adaptive codebook buffer prior to its use by subsequent frames. COPYRIGHT: (C)2006,JPO&NCIPI |
