mediaLib Library Functions          mlibSignalLPC2LSPS16(3MLIB)



NAME
     mlibSignalLPC2LSPS16 - convert linear  prediction  coeffi-
     cients to line spectral pair coefficients

SYNOPSIS
     cc [ flag... ] file... -lmlib [ library... ]
     #include 

     mlibstatus mlibSignalLPC2LSPS16(mlibs16 *lsp, const mlibs16 *lpc,
          mlibs32 lscale, mlibs32 order);


DESCRIPTION
     The mlibSignalLPC2LSPS16() function converts linear  pred-
     iction coefficients to line spectral pair coefficients.


     The line spectral pair (LPS) coefficients are defined as the
     roots of the following two polynomials:

                           -(M]1)     -1
            P(z) = A(z) ] z      * A(z  )

                           -(M]1)     -1
            Q(z) = A(z) - z      * A(z  )



     where A(z) is the inverse filter

                       M          -i
            A(z) = 1- SUM a(i) * z
                      i=1



     Note that since P(z) is symmetric and Q(z) is  antisymmetric
     all  roots  of  these polynomials are on the unit circle and
     they alternate each other. P(z) has a root at z =  -1  (w  =
     PI) and Q(z) has a root at z = 1 (w = 0).


     The line spectral frequency (LPF) are the angular  frequency
     of the line spectral pair (LPS) coefficients.

            q = cos(w)



     where q is the LPS and w is the LPF.





SunOS 5.11           Last change: 2 Mar 2007                    1






mediaLib Library Functions          mlibSignalLPC2LSPS16(3MLIB)



     See Fundamentals of Speech Recognition by  Lawrence  Rabiner
     and Biing-Hwang Juang, Prentice Hall, 1993.

PARAMETERS
     The function takes the following arguments:

     lsp       The line spectral pair coefficients in Q15 format.


     lpc       The linear prediction coefficients.


     lscale    The scaling factor of the linear prediction  coef-
               ficients,  where  actualdata = inputdata * 2**(-
               scalingfactor).


     order     The order of the linear prediction filter.


RETURN VALUES
     The function returns MLIBSUCES if  successful.  Otherwise
     it returns MLIBFAILURE.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Committed                   
    
     MT-Level                     MT-Safe                     
    


SEE ALSO
     mlibSignalLSP2LPCS16(3MLIB), attributes(5)














SunOS 5.11           Last change: 2 Mar 2007                    2