mlib_SignalLPC2LSP_S16(3MLIB)				    mediaLib Library Functions				     mlib_SignalLPC2LSP_S16(3MLIB)

NAME

       mlib_SignalLPC2LSP_S16 - convert linear prediction coefficients to line spectral pair coefficients

SYNOPSIS

       cc [ flag... ] file... -lmlib [ library... ]
       #include <mlib.h>

       mlib_status mlib_SignalLPC2LSP_S16(mlib_s16 *lsp, const mlib_s16 *lpc, mlib_s32 lscale, mlib_s32 order);

DESCRIPTION

       The mlib_SignalLPC2LSP_S16() function converts linear prediction 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.

       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 coefficients, where actual_data = input_data * 2**(-scaling_factor).

       order	       The order of the linear prediction filter.

RETURN VALUES

       The function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Evolving			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       mlib_SignalLSP2LPC_S16(3MLIB), attributes(5)

SunOS 5.10							    10 Nov 2004 				     mlib_SignalLPC2LSP_S16(3MLIB)