Patent ID: 6304843
Filing Date: 2001-10-16
Classification: G10L

Abstract:
An apparatus for reconstructing a linear prediction synthesis filter excitation signal, the apparatus comprising:means for receiving parameters representative of a signal's magnitude and phase spectrum, and for producing therefrom a deterministic signal comprising a magnitude spectrum and a phase spectrum; andmeans for receiving the deterministic signal and a noise signal and for reconstructing therefrom the linear prediction synthesis filter excitation signal,wherein the phase spectrum is derived substantially from the formula:.phi.E(.omega.)=-tan.sup.-1 (.sup..alpha.sin .omega. /.sub.1-.alpha.cos .omega.)-tan.sup.-1 (.sup..gamma.sin .omega. /.sub.1-.gamma.cos .omega.)+2 tan.sup.-1 (.sup.sin .omega. /.sub..beta.-cos .omega.)where.phi.E (.omega.) represents the phase at frequency .omega.,.alpha. is a predetermined constant,.gamma. represents a desired degree of spectral tilting, and.beta. is substantially equal to the mean average of .alpha. and .gamma..