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# mlib_signallsp2lpc_s16(3mlib) [sunos man page]

```mlib_SignalLSP2LPC_S16(3MLIB)				    mediaLib Library Functions				     mlib_SignalLSP2LPC_S16(3MLIB)

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

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

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)

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 postfix), the scaling factor of the output data will be calculated 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 coefficients, 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 attributes:

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

mlib_SignalLPC2LSP_S16(3MLIB), attributes(5)

SunOS 5.10							    10 Nov 2004 				     mlib_SignalLSP2LPC_S16(3MLIB)```

## Check Out this Related Man Page

```mlib_SignalLPC2LSP_F32(3MLIB)				    mediaLib Library Functions				     mlib_SignalLPC2LSP_F32(3MLIB)

NAME
mlib_SignalLPC2LSP_F32 - convert linear prediction coefficients to line spectral pair coefficients

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

mlib_status mlib_SignalLPC2LSP_F32(mlib_f32 *lsp, const mlib_f32 *lpc, mlib_s32 order);

DESCRIPTION
The mlib_SignalLPC2LSP_F32() 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.

lpc	       The linear prediction coefficients.

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			   |
+-----------------------------+-----------------------------+