getfburg.3

speech signal process tools

.\" Copyright (c) 1986-1990 Entropic Speech, Inc.
.\" Copyright (c) 1997 Entropic Research Laboratory, Inc. All rights reserved.
.\" @(#)getfburg.3	1.2 18 Apr 1997 ESI/ERL
.ds ]W (c) 1997 Entropic Research Laboratory, Inc.
.TH GET_FBURG 3\-ESPSsp 18 Apr 1997
.SH NAME
get_fburg \- Compute reflection coefficients using fast modified Burg method.
.SH SYNOPSIS
.nf
.ft B
 
get_fburg (x, lnt, c, order, rc, pgain)
float *x;
int   lnt;
float *c;
int   order;
float *rc;
float *pgain;

.ft
.SH DESCRIPTION
.PP
This function computes the reflection coefficients and the lpc filter
coefficients directly from sampled data.  The algorithm is a faster
version of the modified Burg method used in
\fIget_burg\fP(3\-\s-1ESPSsp\s+1);
relative to that function, \fIget_fburg\fP
provides computational savings on the order of 50 to 70 per cent.
.PP
Unlike the standard Burg algorithm, where reflection coefficients are
obtained from the forward and backward prediction errors, this
(unpublished) method works with the sample covariance matrix of the
data.
.PP
\fIget_fburg\fP takes data of size \fIlnt\fP in array \fIx\fP
as input, and computes \fIorder\fP reflection coefficients \fIrc\fP[1]
to \fIrc\fP[\fIorder\fP], \fIorder\fP lpc filter coefficients 
\fIc\fP[1] to \fIc\fP[\fIorder\fP], and the lpc filter gain
*\fIpgain\fP.  
.SH BUGS
None known
.SH SEE ALSO
.PP
.nf
\fIestimate_covar\fP(3\-\s-1ESPS\s+1sp), \fIget_burg\fP(3\-\s-1ESPS\s+1sp),
\fIget_vburg\fP(3\-\s-1ESPS\s+1sp), \fIstrcov_auto\fP(3\-\s-1ESPS\s+1sp),
\fIgenburg\fP(3\-\s-1ESPS\s+1sp), \fIcompute_rc\fP(3\-\s-1ESPS\s+1sp)
.fi
.SH REFERENCES
.\" an internal reference is Shankar Narayan, ETM-S-86-49:ssn, 
.\" Spectrum Analysis of periodic data,
.SH AUTHOR
.PP
Program and man page by Shankar Narayan; revisions by John Shore