A METHOD TO DETERMINE THE EXCITATION PULSE POSITIONS WITHIN A SPEECH FRAME

摘要

A method of determining the positions within a speech frame for a given number (N=j+N1, N2) of excitation pulses in a linear predictive speech encoder. The method is a combination of two known methods. In accordance with the invention, the positions of the excitation pulses are calculated in a number of calculation stages (j) in accordance with the first method and the positions of the excitation pulses are calculated in a number of calculation stages (N1, N2, ..., NL) in accordance with the second method, each with a starting point from one of a number of positions (mi, mk, mr) calculated in accordance with the first method, therewith to obtain one of a number (L) of pulse placements, and the proportion between the number of calculation stages (j and max [N1, N2] respectively) according to the first and the second method respectively is chosen so as to obtain the least calculation complexity for a certain given speech quality. Two different embodiments of the second method are described.