1. A method for analysis-by-synthesis coding of a signal comprising steps of: generating a target vector based on an input signal; generating a plurality of constituent components associated with an synthetic excitation signal, wherein a first constituent component of the plurality of constituent components is based on a shifted version of a second constituent component of the plurality of constituent components; and evaluating error criteria based on the target vector and the plurality of constituent components to determine a gain associated with each constituent component of the plurality of constituent components.