Open Access

Channel Effect Compensation in LSF Domain

EURASIP Journal on Advances in Signal Processing20032003:401704

DOI: 10.1155/S111086570330513X

Received: 15 April 2003

Published: 18 August 2003

Abstract

This study addresses the problem of channel effect in the line spectrum frequency (LSF) domain. LSF parameters are the popular speech features encoded in the bit stream for low bit-rate speech transmission. A method of channel effect compensation in LSF domain is of interest for robust speech recognition on mobile communication and Internet systems. If the bit error rate in the transmission of digital encoded speech is negligibly low, the channel distortion comes mainly from the microphone or the handset. When the speech signal is represented in terms of the phase of inverse filter derived from LP analysis, this channel distortion can be expressed in terms of the channel phase. Further derivation shows that the mean subtraction performed on the phase of inverse filter can minimize the channel effect. Based on this finding, an iterative algorithm is proposed to remove the bias on LSFs due to channel effect. The experiments on the simulated channel distorted speech and the real telephone speech are conducted to show the effectiveness of our proposed method. The performance of the proposed method is comparable to that of cepstral mean normalization (CMN) in using cepstral coefficients.

Keywords

line spectrum frequency channel distortion channel effect compensation robust speech recognition

Authors’ Affiliations

(1)
Department of Computer Science, National Chubei Senior High School
(2)
Department of Electrical Engineering, National Tsing Hua University

Copyright

© Copyright © 2003 Hindawi Publishing Corporation 2003