I am doing dtmfe i need a time delay between each of the 8 numbers, the figure i get is without delay, i need it to be like the second picture

y = [];

for i = 1:8

[y1 Fs] = audioread(strcat('Key',int2str(i),'.wav'));

y = [y; y1];

end

%I need to delay this by 50ms

T1 = Ts*(0:8000-1)';

plot(T1,y)