gaintr.m

这是一个用于语音信号处理的工具箱

%FUNCTION GAINTR constructs the gain contour from the gain parameters, 
%         also decomposes the gain contour into two factors.
%
% USUAGE:  [genv,gb,gntour]=gaintr(ngm);
% INPUT :    ngm == the average gain of each frame
% OUTPUT : genv == the gain envelop
%            gb == the perturbation of the gain contour
%          gntour == the gain contour

function [genv,gb,gntour]=gaintr(ngm);

  %
  % 1. smooth the gain envelope
  %

[nfram,dum]=size(ngm);

gntour=zeros(1,nfram);
gntour(1)=mean( ngm(1,1:4) );
for kf=2:nfram-1
   gntour(kf)=mean([ngm(kf-1,4) ngm(kf,1:4) ngm(kf+1,1)]);  % gaim contour
end
gntour(nfram)=mean( ngm(nfram,1:4) );

genv=medfilt(gntour,5);
genv=genv-mean(genv)+mean(gntour);

  %
  % 2. calculate the gain perturbation
  %
gcpert=(gntour-genv)./genv;

% delete 10% biggest deviation
N1=fix( length(genv)*9/10 );
[dum indx]=sort( abs(gcpert) );
gcpert=gcpert( indx(1:N1) );
gb=std(gcpert);