Digital speech coder having improved long term lag parameter determination

摘要

A method and apparatus is provided for determining the lag Lk of a long term filter (105) in a code excited linear prediction speech coder (100). An open loop lag Lopen is first determined using an autocorrelation function. The open loop lag is then utilized to generate a limited range over which a closed loop search is performed. The range for appropriate values includes lags that are harmonically related to the open loop lag as well as adjacent lags.