v_lpcrf2rr

V_LPCRR2AR convert reflection coefs to autocorrelation coefs [RR,AR]=(RF,P)

 Inputs:  rf(:,n+1)  reflection coefficients: one row per frame
          p          specifies number of rr coefficients to calculate (default=n)
 Outputs: rr(:,p+1)  autocorrelation coefficients
          ar(:,n+1)  AR filter coefficients

0001 function [rr,ar]=v_lpcrf2rr(rf,p);
0002 %V_LPCRR2AR convert reflection coefs to autocorrelation coefs [RR,AR]=(RF,P)
0003 %
0004 % Inputs:  rf(:,n+1)  reflection coefficients: one row per frame
0005 %          p          specifies number of rr coefficients to calculate (default=n)
0006 % Outputs: rr(:,p+1)  autocorrelation coefficients
0007 %          ar(:,n+1)  AR filter coefficients
0008 
0009 %      Copyright (C) Mike Brookes 1997
0010 %      Version: $Id: v_lpcrf2rr.m 10865 2018-09-21 17:22:45Z dmb $
0011 %
0012 %   VOICEBOX is a MATLAB toolbox for speech processing.
0013 %   Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
0014 %
0015 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0016 %   This program is free software; you can redistribute it and/or modify
0017 %   it under the terms of the GNU General Public License as published by
0018 %   the Free Software Foundation; either version 2 of the License, or
0019 %   (at your option) any later version.
0020 %
0021 %   This program is distributed in the hope that it will be useful,
0022 %   but WITHOUT ANY WARRANTY; without even the implied warranty of
0023 %   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0024 %   GNU General Public License for more details.
0025 %
0026 %   You can obtain a copy of the GNU General Public License from
0027 %   http://www.gnu.org/copyleft/gpl.html or by writing to
0028 %   Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.
0029 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0030 
0031 [nf,p1]=size(rf);
0032 p0=p1-1;
0033 if p0
0034    a = rf(:,2);
0035    rr=[ones(nf,1) -a zeros(nf,p0-1)];
0036    e = (a.^2-1);
0037    for n = 2:p0
0038       k=rf(:,n+1);
0039       rr(:,n+1) =k.*e - sum(rr(:,n:-1:2).*a,2);
0040       a = [a+k(:,ones(1,n-1)).*a(:,n-1:-1:1) k];
0041       e = e.*(1-k.^2);
0042    end
0043    ar = [ones(nf,1) a];
0044    r0=sum(rr.*ar,2).^(-1);
0045    rr=rr.*r0(:,ones(1,p1));
0046    if nargin>1 && ~isempty(p)
0047       if p<p0
0048          rr(:,p+2:p1)=[];
0049       else
0050          rr=[rr zeros(nf,p-p0)];
0051          af=-ar(:,p1:-1:2);
0052          for i=p0+1:p
0053             rr(:,i+1)=sum(af.*rr(:,i-p0+1:i),2);
0054          end
0055       end
0056    end
0057 else
0058    rr=ones(nf,1);
0059    ar=rr;
0060 end
0061