Fast pitch modelling for CS-ACELP coder using fermat number transforms

This paper presents a double improvements to reduce the speech coding complexity of the pitch prediction in a code-excited linear prediction (CELP) coder. First, the pitch analysis structure is modified. A new fast pitch modelling by linear-filtering (PMF) procedure will determine the adaptive and stochastic codebook contributions of the excitation signal. Afterwards, an efficient implementation of the PMF-CELP coding is proposed by using number theoretic transforms which can significantly reduce the algorithm computation complexity.