| 摘要 |
<p>The product of the word extracted by long term excitation with the associated long term gain (Ga) is added (SM) to the product of the word extracted by short term excitation with the associated short term gain (Gc). The dataword is filtered using a low-pass filter having a cut-off frequency which is greater than 25 % of the sampling frequency, but less than 50 % of the latter. The filtered code is then combined with the adaptive coded index. Speech is sampled in order to obtain a succession of speech frames, each one comprising a pre-determined number of samples. The parameters for a code excitation-based linear prediction model are determined for each speech frame and these parameters comprise a long term excitation dataword (vi) extracted from an associated coded index (DLT) and an associated short term gain, as well as a short term excitation dataword (cj) extracted from an algebraic coded index (DCT) and an associated short term gain, providing an adaptive coded index obtained from the long term excitation extracted word and the short term excitation extracted word. Independent claims are also included for the following: (1) Speech coding device (CD) for carrying out this method; and (2) Wireless communication terminal provided with the coding device.</p> |
