Patent ID: 6064956
Filing Date: 2000-05-16
Classification: G10L

Abstract:
A method of determining the positions within a speech frame of a given number of excitation pulses in a linear predictive speech encoder in which a speech signal divided in speech frames is analyzed and the analyzed speech signal is synthesized to form a prediction residue and a number of predictive parameters, which, according to a first method, are applied to an excitation processor which filters the prediction residue and the parameters obtained from the excitation processor for each of the desired excitation pulses in accordance with said predictive parameters, wherein according to a second method a speech frame is also divided into a number of phase positions and each phase position is divided into a number of phases and restrictions are inserted to the effect that the phase that is occupied when placing an excitation pulse is prohibited to each subsequent excitation pulse and to each phase position within the speech frame, the method comprising the steps ofa) calculating the positions of the excitation pulses in a number of calculation stages in accordance with the first method;b) calculating the positions of the excitation pulses in a number of calculation stages in accordance with the second method, each stage with a starting point from one of a number of positions calculated in accordance with the first method, therewith to obtain one of a number of pulse placements; andc) choosing the proportion between the number of calculation stages according to the first and the second method, respectively, so as to obtain the least calculation complexity for a certain given speech quality.