%%?name:?SunKangKang??????student?number:?1228
clear?variables;?%deletes?all?variables?in?the?workspace
close?all;?%closes?all?plots
clc;?%clears?the?command?window
%%?E1?Computation?of?the?autocorrelation?function
[yFs]?=?audioread（‘dayu.wav‘）;
max_time_lag=0.1;%set?the?maximum?time?shift?of?the?signal（100ms）
r_ss?=?autocorrelation（y?max_time_lag）;
time_lag?=?linspace（0size（r_ss1）/Fs*1000size（r_ss1））;
%Plot?r_ss?and?display?the?time?shift?on?the?x-axis?and?the?correlation?on?the?y-axis.
figure
hold?on
xlabel（‘time?lag（ms）‘）;
ylabel（‘r_s_s‘）;
plot（time_lagr_ss）;
hold?off
%%?E2?Determining?the?fundamental?frequency
%find?the?maxima?of?acf?by?using?the?function?sort（）
%B?sort?the?value?of?acf?in?increasing?order?I?returns?the?corresponding?index?of?value
[BI]?=?sort（r_ss）;
num=size（I1）-1;
%The?voiced?speech?of?a?typical?adult?male?will?have?a?fundamental?frequency
%from?85?to?180?Hz?and?that?of?a?typical?adult?female?from?165?to?255?Hz.So?the
%minimum?period（interval）?in?sample?between?maxima?should?be?approximately?Fs/250=64.?The
%next?maximum?should?be?after?at?least?approximately?64?samples.
while?（I（num）????num=num-1;???%B?sort?the?value?of?acf?in?increasing?order
end
%Then?we?use?the?period?in?sample?calculated?from?the?first?2?maxima?to
%estimate?the?position?of?other?maxima.?The?possible?position?of?next
%maximum?=?the?position?of?previous?maximum?+?period?in?sample.?Next?we
%search?for?the?maxima?a