Patent ID: 6470313
Filing Date: 2002-10-22
Classification: G10L

Abstract:
A method of coding a speech signal which signal comprises a sequence of subframes containing digitised speech samples, the method comprising, for each subframe:(a) selecting a quantised vector d(i) comprising at least one pulse, wherein the number m and position of pulses in the vector d(i) may vary between subframes; (b) determining a gain value gc for scaling the amplitude of the quantised vector d(i) or of a further vector c(i) derived from the quantised vector d(i), wherein the scaled vector synthesizes a weighted residual signal {tilde over (s)}; (c) determining a scaling factor k which is a function of the ratio of a predetermined energy level to the energy in the quantised vector d(i); (d) determining a predicted gain value &gcirc;c on the basis of one or more previously processed subframes, and as a function of the energy Ec of the quantised vector d(i) or said further vector c(i) when the amplitude of the vector is scaled by said scaling factor k; and (e) determining a quantised gain correction factor {circumflex over (&ggr;)}gc using said gain value gc and said predicted gain value &gcirc;c.