Patent ID: 7792670

Claim:
A method for coding speech by a speech coder, the method comprising the steps of: generating, by a processor, a plurality of weighted adaptive codebook vectors ( c ′ 0 (n) . . . c ′ K′ (n)) based on a sub-sample resolution delay value, an adaptive codebook, and a weighted synthesis filter; receiving an input speech signal s(n); generating a target vector p(n) based on the input speech signal; generating a plurality of correlation terms (R cc (i,j),R pc (i)) based on the target vector p(n) and the plurality of weighted adaptive codebook vectors; generating a plurality of symmetric multi-tap long-term predictor filter coefficients (β i 's) based on the plurality of correlation terms, wherein the plurality of symmetric multi-tap long-term predictor filter coefficients comprises coefficients β 0 =αθ and β 1 = ( 1 - α ) ⁢ θ 2 and wherein α is a shaping coefficient of a shaping filter and θ is an overall long-term predictor gain value; and constraining values of the shaping coefficient α such that a characteristic of the shaping filter is low-pass.