Joint optimization of linear predictors in speech

Formant and pitch predictors which are jointly optimized are discussed. The first configuration considered is a combination prediction error filter (in either a transversal or lattice form) that performs the function of both a formant and a pitch filter. Although a transversal combination filter outperforms the conventional F-P (formant followed by pitch) sequential solution, the combination filter exhibits a high incidence of nonminimum phase filters. For an F-P cascade connection, combined solutions and iterated sequential solutions are found. They yield high prediction gains than the conventional F-P sequential solution. Furthermore, a practical implementation of the iterated sequential solution is developed such that both the formant and pitch filters are minimum phase. This implementation leads to decoded speech of higher perceptual quality than the conventional sequential solution.<>