matlab - Algorithm that process the autocorrelation function for each frame in order to extract the pitch period during that frame -

i have speech signal divided n frames. have loop loops through each frame , calculates auto correlation. don't know how can extract pitch period of each frame. there function can use? snippet of code have follows:

for j = 0:n     frame{j+1} = y1((framelength*(j))+1 : framelength*(j+1));        = minimumlag:maximumlag         autocorrelation(i) = autocorrelate(framelength,i,frames{j+1});    end; end; 

see reference link looks simple peak search on resultant sequence. reference suggests 2nd strongest peak.