decode.m

wav声音文件的通过多脉冲激励编码器

function decode(v,pitch_marks,bvalue,corparameter1,corparameter2,poles_num,frmsize,win_length)
syms z;
syms n;
Bz=1-bvalue*z^(-pitch_marks);%prediction error filter
bnreciprocal=iztrans(1/Bz,z,n)%short trem prediction error
%caculate A
Az1=1;
Az2=1;
for k=1:poles_num   
Az1=Az1-corparameter1(k)*z^(-k);
Az2=Az2-corparameter2(k)*z^(-k);
end
%caculate u[n] ,that is e[n]
un1=zeros(1,win_length);
un2=zeros(1,win_length);
for i=1:pitch_marks
   
    %  bnre(i)=
    subs(bnreciprocal,n,i)
    %un(i)=conv(v,bnre)
   % if i<=win_length
     

    %un1(i)=conv(v(i),bnre)
    %else
    %bnre=subs(bnreciprocal,n,i-win_length)
    %un2(i-win_length)=conv(v(i),bnre)
    %end
end
%caculate  the z transfrom of un1 and un2
Uz1=simple(ztrans(un1,n,z));
Uz2=simple(ztrans(un2,n,z));
%caculate the predict value of sn
Sz1=Uz1*(1/Az1);
Sz2=Uz2*(1/Az2);
sn1=iztrans(Sz1,z,n);
sn2=iztrans(Sz2,z,n);
sn=zeros(1,frmsize);
for i=1:frmsize
    if i<=win_length
    sn(i)=subs(sn1,n,i); 
    else
    sn(i)=subs(sn2,n,i-win_length); 
    end
end