mlib_SignalLPC2LSP_S16(3MLmediaLib Library Functimlib_SignalLPC2LSP_S16(3MLIB)NAMEmlib_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 coef‐
ficients 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 │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOmlib_SignalLSP2LPC_S16(3MLIB), attributes(5)SunOS 5.10 2 Mar 2007 mlib_SignalLPC2LSP_S16(3MLIB)
