The Skipping Technique: A Simple and Fast Algorithm to Find the Pitch in CELP Vocoder

JooHun LEE  MyungJin BAE  Souguil ANN  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E78-A   No.11   pp.1571-1575
Publication Date: 1995/11/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Digital Signal Processing
pitch search,  correlation function,  CELP vocoder,  computation time reduction,  skipping technique,  

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A fast pitch search algorithm using the skipping technique is proposed to reduce the computation time in CELP vocoder. Based on the characteristics of the correlation function of speech signal, the proposed algorithm skips over certain ranges in the full pitch search range in a simple way. Though the search range is reduced, high speech quality can be maintained since those lags having high correlation values are not skipped over and are used for search by closed-loop analysis. To improve the efficiency of the proposed method, we develop three variants of the skipping technique. The experimental results show that the proposed and the modified algorithm can reduce the computation time in the pitch search considerably, over 60% reduction compared with the traditional full search method.