PARAMETRIC SPEECH CODING
 Inventor: Kari Juhaiii Jarvinen, Tampere. Finland
 Assignees: Nokia Mobile Phones Ltd., Salo;
Nokia Telecommunications Oy, Espoo, both of Finland
 Appl. No.: 382,875
 Filed: Feb. 3,1995
 Foreign Application Priority Data
Feb. 8, 1994 [FI] Finland i 940577
 Int. CL6 G10L3/02
 U.S. CI 395/2.29; 395/2.28
 Field of Search 395/2.29,2.31.
 References Cited
U.S. PATENT DOCUMENTS
4,752,956 6/1988 Sluijter 381/38
5,018,200 5/1991 Ozawa 381/36
5,115,469 5/1992 Tanigushi .et al 381/36
5,483,668 1/1996 Malkamaki et al 455/33.2
5,517,511 5/1996 Hardwick et al 371/37.4
5,579,433 11/1996 Jarvinen 395/228
Leich. H., 'Technique De Codage De La Parole", Revue HF,
vol. 17, No. 1/02/03, 1 Jan. 1993, pp. 37-50.
Lee, Hwang S. et al., "A Vector Quantization Adaptive
Predictive Coder", IEEE Aug. 1987, vol. 3, pp. 1272-1277.
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.
17 Claims, 3 Drawing Sheets