www.gusucode.com > 语音信号处理工具箱 - Voicebox源码程序 > Voicebox\lpcconv.m
function s=lpcconv(from,to,x,y,np)
%LPCCONV(from,to,x,y)->s convert between LPC parameter sets
%
% The output is a string that may be passed to eval(s)
% x and y are optionally the input and output matrices
% and np the new value of the order p.
% with one frame stored per row. from and to are taken
% from the following list which also gives the column dimension:
%
% 1 ar p+1 Autoregressive coevfficients: ar(1)=1 always.
% 2 cc p Complex cepstral coefficients
% 3 ls p Line spectrum pair frequencies (normalized Hz)
% 4 zz p Z-plane roots
% 5 ss p S-plane roots (normalized Hz)
% 6 rf p Reflection coefficients (= -PARCOR coefs)
% 7 ao p Area ratios
% 8 aa p+2 Vocal tract areas: aa(p+2)=1 always
% 9 rr p+1 Autocorrelation coefficients
% 10 dl p DCT of log area function
% 11 lo p Log area ratios
% 12 la p+1 Log areas: la(1)=0 always
% 13 ra p+1 Autocorrelation coefs of inverse filter
% 14 ff p+2 Fourier transform of forward filter (all-pole)
% 15 pf p+2 Power spectrum of forward filter (all-pole)
% 16 gc p Gain and cos(w) of each formant
% 17 im p+1 Impulse response of forward filter
% Copyright (C) Mike Brookes 1998
%
% Last modified Tue Jan 4 21:48:54 2000
%
% VOICEBOX is a MATLAB toolbox for speech processing. Home page is at
% http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% This program is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2 of the License, or
% (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
% GNU General Public License for more details.
%
% You can obtain a copy of the GNU General Public License from
% ftp://prep.ai.mit.edu/pub/gnu/COPYING-2.0 or by writing to
% Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
nm=['aa';'am';'ao';'ar';'cc';'db';'dl';'ff';'fq';'im';'is';'la';'lo';'ls';'pf';'ra';'rf';'rr';'ss';'zz';];
nx=[...
0 17 3 17 17 17 7 17 0 17 17 17 17 17 17 17 17 17 17 17;...
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;...
17 17 0 17 17 17 17 17 0 17 17 17 17 17 17 17 17 17 17 17;...
17 18 17 0 5 6 17 8 0 10 17 17 17 14 15 16 17 18 20 20;...
4 4 4 4 5 6 4 4 0 4 4 4 4 4 15 4 4 4 4 4;...
15 15 15 15 15 0 15 15 0 15 15 15 15 15 15 15 15 15 15 15;...
1 1 1 1 1 1 0 1 0 1 1 1 1 1 1 1 1 1 1 1;...
15 15 15 15 15 15 15 0 0 15 15 15 15 15 15 15 15 15 15 15;...
20 20 20 20 20 20 20 20 0 20 20 20 20 20 20 20 20 20 20 20;...
4 4 4 4 4 4 4 4 0 0 4 4 4 4 4 4 4 4 4 4;...
17 17 17 17 17 17 17 17 0 17 0 17 17 17 17 17 17 17 17 17;...
17 17 17 17 17 17 17 17 0 17 17 0 17 17 17 17 17 17 17 17;...
17 17 17 17 17 17 17 17 0 17 17 17 0 17 17 17 17 17 17 17;...
4 4 4 4 4 4 4 4 0 4 4 4 4 0 4 4 4 4 4 4;...
5 18 5 5 5 5 5 5 0 5 5 5 5 5 0 5 5 18 5 5;...
15 15 15 15 15 15 15 15 0 15 15 15 15 15 15 0 15 15 15 15;...
1 18 3 4 4 4 1 4 0 4 11 12 13 4 4 4 0 18 4 4;...
4 2 4 4 4 4 4 4 0 4 4 4 4 4 4 4 4 0 4 4;...
20 20 20 20 20 20 20 20 0 20 20 20 20 20 20 20 20 20 0 20;...
4 4 4 4 5 4 4 4 0 4 4 4 4 4 4 4 4 4 19 0;...
];
na=size(nm,1);
b=256*nm(:,1)+nm(:,2);
jf=find(b==256*from(1)+from(2));
jt=find(b==256*to(1)+to(2));
if length([jf jt])~=2
[x,idx]=sort(b);
error(sprintf('lpcxx2yy types are: %s',[nm(idx,:)';' '*ones(1,na)]));
end
if nargin<3 s=nm(jf,:); else s=x; end
while jf ~= jt
jn=nx(jf,jt);
if jn==0
error(sprintf('cannot convert between %s and %s',nm(jf,:),nm(jt,:)));
end
s=sprintf('lpc%s2%s(%s)',nm(jf,:),nm(jn,:),s);
jf=jn;
end
if nargin<4 sn=nm(jt,:); else sn=y; end
s=sprintf('%s=%s;',sn,s);