The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 25, 1993
Filed:
Jul. 31, 1991
Tor B Minde, Lule.ang., SE;
Telefonaktiebolaget LM Ericsson, Stockholm, SE;
Abstract
The invention relates to a method of coding a sampled speech signal vector by selecting an optimal excitation vector in an adaptive code book. This optimal excitation vector is obtained by maximizing the energy normalized square of the cross correlation between the convolution of the excitation vectors with the impulse response of a linear filter and the speech signal vector. Before the convolution the vectors of the code book are block normalized with respect to the vector component largest in magnitude. In a similar way the speech signal vector is block normalized with respect to its component largest in magnitude. Calculated values for the squared cross correlation C.sub.I and the energy E.sub.I and stored corresponding values C.sub.M, E.sub.M for the best excitation vector so far are divided into a mantissa and a scaling factor with a limited number of scaling levels. The number of levels can be different for squared cross correlation and energy. During the calculation of the products C.sub.I .multidot.E.sub.M and E.sub.I .multidot.C.sub.M, which are used for determining the optimal excitation vector, the respective mantissas are multiplied and a separate scaling factor calculation is performed.