Speech coder

摘要

A long-period prediction circuit (160), which is provided in this speech coder and outputs an optimum delay code of delay codes indicative of a pitch correlation of a speech signal, extracts delay codes by selecting a predetermined section of delay codes and/or while evenly or unevenly thinning out the delay codes, conducts preliminary selection of delay codes through closed-loop search of the extracted delay codes and determines an optimum delay code by executing closed-loop search with respect to the preliminarily selected delay codes. <MATH>