mediaLib Library Functions          mlibSignalLSP2LPCS16(3MLIB)



NAME
     mlibSignalLSP2LPCS16, mlibSignalLSP2LPCS16Adp - convert
     line spectral pair coefficients to linear prediction coeffi-
     cients

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

     mlibstatus mlibSignalLSP2LPCS16(mlibs16 *lpc,
          mlibs32 lscale, const mlibs16 *lsp, mlibs32 order);


     mlibstatus mlibSignalLSP2LPCS16Adp(mlibs16 *lpc,
          mlibs32 *lscale, const mlibs16 *lsp, mlibs32 order);


DESCRIPTION
     Each of the functions in this group converts  line  spectral
     pair coefficients to linear prediction 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)




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mediaLib Library Functions          mlibSignalLSP2LPCS16(3MLIB)



     where q is the LPS and w is the LPF.


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


     Note for functions with adaptive scaling  (with  Adp  post-
     fix),  the  scaling factor of the output data will be calcu-
     lated based on the actual  data;  for  functions  with  non-
     adaptive  scaling  (without Adp postfix), the user supplied
     scaling factor will be used and the output will be saturated
     if necessary.

PARAMETERS
     Each function takes the following arguments:

     lpc       The linear prediction coefficients.


     lscale    The scaling factor of the line spectral pair coef-
               ficients,  where actualdata = outputdata * 2**(-
               scalingfactor).


     lsp       The line spectral pair coefficients in Q15 format.


     order     The order of the linear prediction filter.


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

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

















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mediaLib Library Functions          mlibSignalLSP2LPCS16(3MLIB)



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


SEE ALSO
     mlibSignalLPC2LSPS16(3MLIB), attributes(5)












































SunOS 5.11           Last change: 2 Mar 2007                    3