資源簡(jiǎn)介
東西真的很不錯(cuò) 畢業(yè)設(shè)計(jì)包過。。。。。。。。
代碼片段和文件信息
function?[]=ssb()
t0=0.004999;???
%?仿真的持續(xù)時(shí)間0.004999s?5000個(gè)采樣點(diǎn)
%?0.049999?50000個(gè)采樣點(diǎn)
%?0.099999?100000個(gè)采樣點(diǎn)
ts=0.000001;
fc=50000;???%載波頻率
snr=20;?%信噪比,以dB來表示
snr_lin?=10^(snr/10);?%dB轉(zhuǎn)換
fs=1/ts;
df=0.3;??%頻率分辨率
t=(0:ts:t0);
%載波信號(hào)生成
c=cos(2*pi*fc.*t);?????
%生成消息信號(hào)(正弦信號(hào))
fc_message=5000;???????????????%調(diào)制信號(hào)頻率
m=cos(2*pi*fc_message.*t);
%方波信號(hào)
%m=[ones(11000)-2*ones(12000)zeros(12000)];
%DSB載波調(diào)制
%相乘器
dsb=c.*m;
%演示雙邊帶調(diào)制頻譜
[DSBdsbdf1]=fftseq(dsbtsdf);
DSB=DSB/fs;
f=(0:df1:df1*(length(dsb)-1))-fs/2;
clear?dsb
%低通濾波器(調(diào)制器)
f_cutoff=50000;??????????%截止頻率
n_cutoff=floor(f_cutoff/df1);
HL_M=zeros(size(f));????????
HL_M(1:n_cutoff)=ones(1n_cutoff);
HL_M(length(f)-n_cutoff+1:length(f))=ones(1n_cutoff);
%高通濾波器(調(diào)制器)
f_cutoff=50000;
n_cutoff=floor(f_cutoff/df1);
HH_M=ones(size(f));
HH_M(1:n_cutoff)=zeros(1n_cutoff);
HH_M(length(f)-n_cutoff+1:length(f))=zeros(1n_cutoff);
clear?HH_M
%濾除上邊帶
SSB_M=DSB.*HL_M;
ssb_m=real(ifft(SSB_M))*fs;
%重新整理信號(hào)長(zhǎng)度
ssb=zeros(1length(t));
for?i=1:length(t)
????ssb(i)=ssb_m(i);
end
clear?ssb_m
%生成噪聲
signal_power=spower(ssb(1:length(t)));?%計(jì)算已調(diào)信號(hào)功率
noise_po
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