Patent ID: 6847928
Filing Date: 2005-01-25
Classification: G10L

Abstract:
1. A speech decoder that decodes parameters received in frames and reconstructs a speech based on the received parameters, comprising: a first-stage decoding circuit that generates excitation vectors from the received parameters: a second-stage decoding circuit that performs a speech synthesis, using the excitation vectors, to obtain a reconstructed speech; an adaptive preprocessing filter, located between the first-stage and second-stage circuits, that emphasizes, to a degree, a harmonic component of at least one of the excitation vectors; and an error frame counter that counts successive error frames that contain a transmission error, the error frame counter operably connected to the adaptive preprocessing filter to decrease the degree of emphasis performed thereby as a count of the successive error frames increases, wherein the error frame counter disables the adaptive preprocessing filter to effect zero emphasis on the at least one of the excitation vectors when the count of the successive error frames reaches a predetermined number.