Patent ID: 7080007

Claim:
A Speech Absence Probability (SAP) computing device for computing the SAP indicating probability that speech is absent in a m th frame, from a first through Nc th posteriori (Nc means the total number of channels) Signal to Noise Ratios (SNR) calculated with regard to the m th frame of a speech signal and a first through Nc th predicted SNRs predicted with regard to the m th frame, the SAP computing device comprising: a first through Nc th likelihood ratio generators for generating a first through Nc th likelihood ratios from the first through Nc th posterior SNRs and the first through Nc th predicted SNRs, and outputting them; a first multiplying unit for multiplying the first through Nc th likelihood ratios by a predetermined a priori probability, and outputting the multiplication results; an adding unit for adding each of the multiplication results received from the first multiplying unit to a predetermined value, and outputting the added results; a second multiplying unit for multiplying the added results received from the adding unit and outputting the multiplication result; and a inverse number calculator for calculating inverse number of the multiplication result received from the second multiplying unit and outputting the calculated inverse number as the SAP.