Method and device for enlarged bandwidth speech coding, allowing in particular an improved quality of voiced frames

摘要

The linear prediction filter (FP) is updated using the short term excitation word which has been filtered using a filter with an order greater than or equal to 1 (FLT1), whose coefficients depend on the value of the long term gain (Ga), so that the short term excitation contribution is reduced until the long term excitation gain is greater than a threshold value. 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 adaptively coded index (DLT) and an associated long term gain, as well as a short term excitation dataword (cj) extracted from an fixed coded index (DCT) using a linear prediction filter and an associated short term gain (Gc). The adaptively coded index is updated using the extracted long and short term excitation datawords. 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.