| 摘要 |
<p>This invention is a new kind of parametric speech coding system in which the parametrization according to a speech production model is carried out not only on the speech signal to be coded but also on the decoded, that is, synthesized speech signal. A parametric representation (207) of the synthesized signal is compared with a parametric representation (203) of the original speech signal and the coding functions are controlled according to their difference. At first, parametrization (205) according to the speech production model used in the encoding is carried out on the decoded speech signal. Next, the parameter values formed from the synthesized speech signals are compared (204) with the parameter values (203) calculated, in the encoder, from the speech signal to be coded. A known distance measure can be used in carrying out the comparison. The coding functions are controlled by means of a shaping block (202) in such a way that the difference indicated by the distance measure is made as small as possible. <IMAGE></p> |
