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%程序功能：BPSK信號解調??2018.03.07?????????????%
%程序流程：碼元同步?載波同步?判決輸出????????????%
%要????求：采樣率為碼元速率的整數倍????????????????%
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clc;
close?all;
clear?all;


Fs?=?32e6;?????????%信號采樣率
Fb??=?500000;??????%碼元速率?
Fc??=?2e6;?????????%實際載波頻率
ts??=?1/Fs;????????%時間分辨率?
wfc?=?Fc+10000;?????%初始頻率
Rate?=?Fs/Fb;??????%每個碼元樣點個數?
num?=?5e4;?????????%樣點個數

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%生成BPSK信號%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%%%%%帶通濾波器設計%%%%
Fstop1?=?Fc-Fb-0.2e6;????????????%?First?Stopband?Frequency
Fpass1?=?Fc-Fb;????????????%?First?Passband?Frequency
Fpass2?=?Fc+Fb;????????????%?Second?Passband?Frequency
Fstop2?=?Fc+Fb+0.2e6;????????????%?Second?Stopband?Frequency
Dstop1?=?0.0001;??????????%?First?Stopband?Attenuation
Dpass??=?0.057501127785;??%?Passband?Ripple
Dstop2?=?0.0001;??????????%?Second?Stopband?Attenuation
dens???=?20;??????????????%?Density?Factor
%?Calculate?the?order?from?the?parameters?using?FIRPMORD.
[N?Fo?Ao?W]?=?firpmord（[Fstop1?Fpass1?Fpass2?Fstop2]/（Fs/2）?[0?1?...
??????????????????????????0]?[Dstop1?Dpass?Dstop2]）;
%?Calculate?the?coefficients?using?the?FIRPM?function.
bfir1??=?firpm（N?Fo?Ao?W?{dens}）;


LData?=?ceil（num/Rate）;???????%碼元數量
Symbs?=?zeros（1LData）;??
for?i=1:1:LData
????Symbs（i）?=?randi（21）-1;???%隨機產生符號
end

constellation_map=[0?pi];??????%星座圖
Pskmodu?=?constellation_map（Symbs+1）;
angl?=?zeros（num1）;
for?i=1:1:num????
???angl（i）?=?Pskmodu（floor（（i-1）/Rate）+1）;????
end

SNR?=?-30;

BPSK_Sig?=?zeros（1num）;

for?k=1:1:num
????BPSK_Sig（k）?=?10000*（cos（2*pi*Fc*k*ts+angl（k））+sqrt（10^（SNR/10））*randn（11））;?%%產生信號并加噪聲
end

Data?=?conv（BPSK_Sigbfir1）;

if（num>length（Data））
????num?=?length（Data）;????%判斷是否超過數據長度?若超過則num等于數據長度
end

%低通濾波器設計
Fpass?=?0.5e6;???????????%?Passband?Frequency?
Fstop?=?2e6;?????????????%?Stopband?Frequency
Dpass?=?0.057501127785;??%?Passband?Ripple
Dstop?=?0.0001;??????????%?Stopband?Attenuation
dens??=?20;??????????????%?Density?Factor
%?Calculate?the?order?from?the?parameters?using?FIRPMORD.
[N?Fo?Ao?W]?=?firpmord（[Fpass?Fstop]/（Fs/2）?[1?0]?[Dpass?Dstop]）;
%?Calculate?the?coefficients?using?the?FIRPM?function.
bfir2??=?firpm（N?Fo?Ao?W?{dens}）;?%濾波器系數
FirCoeNum?=?length（bfir2）;????????????%濾波器長度

phase_Save?=?zeros（floor（num/Rate）1）;????%保存的角度
CodeS_Save?=?zeros（floor（num/Rate）1）;????%輸出碼元

Freq_Out???=?zeros（num1）;?????????????%載頻輸出
PhaseDert_Out?=?zeros（num1）;??????????%相位差輸出

Data_DoFreq?=?zeros（1num）;????????????%下變頻后數據
Data_LoPass?=?zeros（1num）;????????????%低通濾波后數據
????????
phase?=?0;?%相位
ss?=?0;
dert_w?=?0;
dert_f?=?0;

temp?=?0;
XX?=?0;
YY?=?0;

%%%考慮到濾波器因素跳過前面一些點
for?k=1:1:num????????
????Data_DoFreq（k）?=?Data（k）*exp（-1j*（phase））;????????????????????%下變頻?并將數據存儲在Data_DoFreq中??
????
????if（k>=FirCoeNum）??????????????????????????????????????????????%因為濾波需要先去的數據?所以等累積的點數大于FircoeNum時再開始濾波???????
????????Data_LoPass（k）?=?Data_DoFreq（k+1-FirCo

?屬性????????????大小?????日期????時間???名稱
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?????文件????????5621??2018-03-07?19:17??BPSK_Demod.m