Manual Pages for UNIX Operating System command usage for man mlib_SignalLSP2LPC_S16_Adp

mediaLib Library Functions          mlib_SignalLSP2LPC_S16(3MLIB)



NAME
     mlib_SignalLSP2LPC_S16, mlib_SignalLSP2LPC_S16_Adp - convert
     line spectral pair coefficients to linear prediction coeffi-
     cients

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

     mlib_status mlib_SignalLSP2LPC_S16(mlib_s16 *lpc,
          mlib_s32 lscale, const mlib_s16 *lsp, mlib_s32 order);


     mlib_status mlib_SignalLSP2LPC_S16_Adp(mlib_s16 *lpc,
          mlib_s32 *lscale, const mlib_s16 *lsp, mlib_s32 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          mlib_SignalLSP2LPC_S16(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 actual_data = output_data * 2**(-
               scaling_factor).


     lsp       The line spectral pair coefficients in Q15 format.


     order     The order of the linear prediction filter.


RETURN VALUES
     Each function returns MLIB_SUCCESS if successful.  Otherwise
     it returns MLIB_FAILURE.

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

















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mediaLib Library Functions          mlib_SignalLSP2LPC_S16(3MLIB)



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|


SEE ALSO
     mlib_SignalLPC2LSP_S16(3MLIB), attributes(5)












































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