Adaptive short-term post-filters for speech coders
AssigneeAT&T Corp.
InventorsHong-Goo Kang, Hong Kook Kim
Life of this patent
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Abstract
Methods and systems for filtering synthesized or reconstructed speech are implemented. A filter based on a set of linear predictive coding (LPC) coefficients is constructed by transforming the LPC coefficients to the pseudo-cepstrum, a domain existing between LPC domain and the line spectral frequency (LSF) domain. The resulting filter can emphasize spectral frequencies associated with various formants, or spectral peaks, of an inverse transfer function relating to the LPC coefficients, and can de-emphasize spectral frequencies associated with various spectral minima, or spectral valleys, of the inverse transfer function relating to the LPC coefficients.
Claims21
A method for processing speech, comprising:
- synthesizing a first filter having at least one or more pseudo-cepstral coefficients based on a set of linear predictive coding coefficients, a pseudo-cepstral coefficient being a parameter relating to a pseudo-cepstrum domain existing between the linear predictive coding domain and the line spectral frequency domain;
- and
- processing one or more frames of speech using the first filter.
A filter that processes speech, comprising:
- two or more pseudo-cepstral coefficients based on a set of linear predictive coding coefficients, a pseudo-cepstral coefficient being a parameter relating to a pseudo-cepstrum domain existing between the LPC domain and the line spectral frequency domain.
Dependencies are inferred from the claim text.