www.pudn.com > CELP.ZIP > pitch_syn.m

function [e0,buf]=pitch_syn(e0,buf,index,pgain) 
 
global szsubf pdlyindx sub_cnt del_intv pcode TRUE FALSE 
 
% Decode pitch code obtained from delta search into real index pointing to pitch delay table 
if rem(sub_cnt-1,del_intv)~=0 
    anch=del_intv*fix((sub_cnt-1)/del_intv)+1; 
    index=pcode(anch); 
    for i=1:rem(sub_cnt-1,del_intv) 
        index=index+pcode(anch+i); 
    end 
end 
 
leng=length(buf); 
lb=leng-szsubf; 
 
m=fix(pdlyindx(index)); 
buf(1:lb)=buf((1+szsubf):(lb+szsubf)); 
 
% For lags shorter than frame size(60), expand the adaptive codeword  
% the full codeword length by overlapping and adding the convolution 
if pdlyindx(index)-m<10e-4                          % if integer pitch synthesis 
    if(leng-m)>=lb+1 
        if m<30                                     % Add in 3rd convolution 
            buf((lb+1):(lb+m))=buf((lb-m+1):lb); 
            buf((lb+m+1):(lb+m+m))=buf((lb+1):(lb+m)); 
            buf((lb+m+m+1):leng)=buf((lb+m+1):leng-m); 
        else                                        % Add in 2dn convolution 
            buf((lb+1):(lb+m))=buf((lb-m+1):lb); 
            buf((lb+m+1):leng)=buf((lb+1):leng-m); 
        end 
    else 
        buf((lb+1):leng)=buf((lb+1-m):leng-m); 
    end 
else    % else it's fractional pitch synthesis 
    % Generate fractional pitch delay by interpolation 
    [buf,buf1]=interpolate(buf,lb+1,szsubf,pdlyindx(index)-m,m); 
    buf((lb+1):(leng))=buf1(1:szsubf);    
end 
 
% Synthesize pitch 
e0(1:szsubf)=e0(1:szsubf)+(pgain*buf(lb+1:lb+szsubf)); 
buf(lb+1:lb+szsubf)=e0(1:szsubf);