Orthogonalization search for the CELP based speech coding

摘要

An orthogonal search method for excitation of an algebraic structured random codebook for determining a search reference value comprising a numerator and a denominator term, for use in a CELP speech coding method where a random vector is composed of a few signed pulses, the orthogonal search method characterized by the following steps to calculate the denominator:
referring to an input speech signal, an adaptive vector, a numerical value that is calculated in advance using synthesis filter coefficients, and a random vector formed with a combination of the signed pulses;
orthogonalizing synthesized candidate random vectors for a predetermined synthesized adaptive vector; and
specifying from the orthogonalized random vectors a random vector that minimizes coding distortion.