Patent ID: 6131083
Filing Date: 2000-10-10
Classification: G10L

Abstract:
A speech encoding method of encoding speech parameters representing the spectral envelope of an input speech signal comprising the steps of:obtaining an autocorrelation coefficient from the input speech signal;obtaining first LSF (line spectral frequency) parameters represented by F(k) (k=1, 2, . . . , N; N is the order of the LSF parameters) on the basis of the autocorrelation coefficient;obtaining second LSF parameters f(k) by performing on the first LSF parameters a transformation defined byf(k)=log C(1+A.times.F(k))(A, C=positive constant);quantizing the second LSF parameters to obtain third quantized LSF parameters fq(k) and first codes representing the third LSF parameters; andobtaining fourth LSF parameters Fq(k) by performing on the third LSF parameters an inverse transformation defined byFq(k)=(C.sup.fq(k) -1)/A.