Patent ID: 6993478

Claim:
A system for processing a sequence of input vectors, said input vectors each comprising a plurality of element values, and said system comprising: a digital filter with a filter vector input for receiving said sequence of input vectors obtained from a digitized speech signal and a predictor gain input for controlling characteristics of said filter, said digital filter also having both a current slowly evolving filter estimate output and a previous slowly evolving filter estimate output, said current slowly evolving filter estimate output providing a current filtered estimate vector of current filtered estimate element values of a slowly evolving component of said sequence of input vectors and said previous slowly evolving filter estimate output providing a previous filtered estimate vector of previous filtered estimate element values of said slowly evolving component of said sequence of input vectors; a parameter estimator having an estimator vector input for receiving said sequence of input vectors and a previous slowly evolving filter estimate input coupled to said previous slowly evolving filter estimate output, said parameter estimator further includes, a predictor gain output coupled to said predictor gain input; a smoother module having inputs coupled respectively to at least two outputs of said digital filter, said smoother module having a smoothed estimate output providing a smoothed estimate value of a said previous slowly evolving component; and a slowly evolving component encoder with an input coupled to said smoothed estimate output, wherein when said system receives a current input vector that is one of said sequence of said input vectors, said parameter estimator provides a current predictor gain vector of current predictor gain element values at said predictor gain input each of said current predictor gain element values modifying both one of said current filtered estimate element values at said current slowly evolving filter estimate output and said smoothed estimate value, each of said current predictor gain element values being dependent upon both a said previous filtered estimate vector received at said slowly evolving filter estimate input and a said current input vector received at said estimator vector input, and wherein the slowly evolving component encoder processes said smoothed estimate value to provide a digitized encoded slowly evolving component of the speech signal.