Programmer Guide/SPU Reference/LPCOEFS

LPCOEFS - linear prediction coefs.

Usage:

LPCOEFS x n d type

Inputs:

x	signal vector	no default
n	number of coefficients	def=20
d	pre-emphasis (differentiation factor, 0..1)	def.=1
type	selects the coefficient type	def.=RC

Outputs:

y	coefficients (n or n+1 values)
alpha	error energy
rc	reflection coefficients

Function:

This function computes the LP (linear prediction) coefficients for the speech signal x using the autocorrelation method. The signal vector x must be windowed before being connected to this atom. An optional pre-filtering (differentiation, if d>0) is applied to the signal before the coefficients' iteration. The algorithms used in this function are based on the algorithms published by J.D.Markel and A.H.Gray in "Linear Prediction of Speech".

Linear prediction coefficients selected by input type{| |- |value of type |type of coefficients stored in y |number of coefs. |- |0 or AI |inverse filter coefficients |n+1 |- |1 or RC |reflection coefficients |n |- |2 or AREA |area coefficients |n |- |3 or LOGAREA |logarithmic area coefficients |n |}