clear all; clc;
[y, fs]=wavread('heart12S_crackles.wav');
% fs=44100; length(y)= 535436;  12.14 sec in all.
% sound(y, fs); 播放此音訊
n= 0:length(y) -1 ;
plot(n, y); % 畫出時間軸上的波形

a=1000; b=3000;  k_max=200;

y_fix=y(a:b);
for k=1:k_max
    y_shift=y(a+k:b+k);
    rn(k)= sum(abs(y_fix-y_shift));
end
figure; plot(1:k_max,rn);