%?clc;
%?clear;
%?close?all;
function?Demodulation（s_toutput_file）

%%%%%%%%%%%%%%%%%%%%%%%%%??sample?rate??%%%%%%%%%%%%%%%%%%%%%%%%%
ExtensionFactor=3;??????????????????????????%?raise?sample?rate?3?times
FS=44100;???????????????????????????????????%?sample?rate?of?wave?file
fs=FS*ExtensionFactor;??????????????????????%?sampling?rate
ts=1/fs;

%%%%%%%%%%%%%%%%%%??receive?the?signal:?s_t??%%%%%%%%%%%%%%%%%%%%
%?load?s_t_matlab;????????????????????????????%?s_t:?input?from?data-file
[tmpN]=size（s_t）;??????????????????????????%?points?of?samples
MusicLen=N/ExtensionFactor;?????????????????
t=-N/2*ts:ts:（N/2-1）*ts;

%%%%%%%%%%%%%%%%%%??Obtain?s1_t?and?s2_t?from?s_t?%%%%%%%%%%%%%%%
%通過頻譜圖確定濾波器的大致帶寬值B
Nfft=2^ceil（log2（N）+2）;
df=fs/Nfft;fk=（-Nfft/2:Nfft/2-1）*df;
s_f=ts*fftshift（fft（s_tNfft））;
figure;plot（fkabs（s_f））;
%?LPF得到L+R信號s1_t
B0=15000;???????????????????????????????????%由s_t頻譜圖得到
h=fir1（40[B0]/（fs/2））;?????????????????????%?考慮41階?
s1_t=filter（h1s_t）;???????????????????????%?demodulated?wave
%窄帶濾波得到導頻信號
B1=15000;???????????????????????????????????%?B1-B2（Hz）?BPF
B2=23000;???????????????????????????????????%?
hbpf=fir1（40[B1B2]/（fs/2））;???????????????%?考慮41階
wbpf=filter（hbpf1s_t）;????????????????????%?信號通過系統
f_dao=19000*2;
%帶通濾波得到L-R的DSB信號
B3=23000;???????????????????????????????????%?B3-B4（Hz）?BPF
B4=53000;??????????????????????????????????%?
hbpf1=fir1（40[B3B4]/（fs/2））;??????????????%?考慮41階
wbpf1=filter（hbpf1s_t）;???????????????????%?信號通過系統
%DSB想干解調得到L-R信號
s2_t0=wbpf1*2*cos（2*pi*f_dao）;
B5=20000;???????????????????????????????????%由s_t頻譜圖得到
h=fir1（40[B5]/（fs/2））;?????????????????????%?考慮41階?
s2_t=filter（h1s2_t0）;???????????????????????%?demodulated?wave
????
%%%%%%%%%%%%%%%%%%%%%%??de-mix??%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
rL_t=（s1_t+s2_t）/2;
rR_t=（s1_t-s2_t）/2;
%%%%%%%%%%%%%%%%%%%%%%??Wave?file??%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
X=zeros（MusicLen2）;
for?i=1:MusicLen
????X（i1）=rL_t（ExtensionFactor*i）;?????????%?restore?44.1kHz?sample?rate?????
????X（i2）=rR_t（ExtensionFactor*i）;????????
end
%?WAVWRITE（XFS‘recved_music.wav‘）;
audiowrite（output_fileXFS）;
disp（‘receivedmusic?signal?generated?!‘）;
return;

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2018-10-10?15:39??源碼\
?????文件????????2301??2017-03-02?15:35??源碼\Demodulation.m
?????文件?????????578??2018-10-13?13:47??源碼\Modulation.m
?????文件?????1769516??2017-03-02?15:28??源碼\recved_music.wav
?????文件??????589584??2011-10-16?21:20??源碼\sending_music.wav
?????文件?????1769516??2017-03-01?16:59??源碼\speech.wav
?????文件?????9836561??2017-03-07?10:16??源碼\s_t_matlab.mat
?????文件?????????157??2018-10-13?13:46??源碼\TotalRun.m
?????目錄???????????0??2018-10-10?15:39??演示\
?????文件????36156306??2017-03-07?14:45??演示\10441調頻立體聲廣播MATLAB仿真.mp4
?????文件?????1769516??2017-03-08?10:20??演示\recved_music.wav
?????文件??????????64??2018-10-10?16:34??說明.txt
?????目錄???????????0??2018-10-10?15:38??需求\
?????文件???????24064??2017-02-28?22:00??需求\主要內容及基本要求.doc