Signal processor for analyzing distortion of speech signals

摘要

A speech coder utilizing previously stored sound source vectors to generate synthetic speech, a distortion computing circuit for computing a distortion of synthetic speech from input speech and a selection circuit for selecting the sound source vector that provides minimum distortion. Sound source vectors are stored within a plurality of reduced size code books rather than a single larger code book. A vector adder adds the sound source vectors respectively output from each of the reduced code books thereby generating a single sound source vector for comparison with the input speech. The distortion circuit computes the distortion for this sound source vector by analyzing the sound source vectors respectively output from each of the reduced code books in addition to the sound source vector output from the vector adder. The computational complexity required to determine the distortion is greatly reduced from the complexity required if a single larger code book of sound source vectors is utilized.