A circuit,system,semiconductor chip and mobile telephone for effecting an algebraic codebook search on a signal for transcoding speech

摘要

The present invention relates to a circuit for encoding a speech signal to a digital signal for use in a mobile telephone. Hitherto such encoding has involved a large number of multiply accumulate operations in the algebraic codebook search. The present invention comprises replacing one of more multiply accumulate units with a shift operation. Thus, the present invention is directed to a shift accumulate unit to perform on said speech signal an algebraic codebook search. Significant power efficiencies can be obtained by reducing the reliance upon so many multiply accumulate units.