ruiliclutter.m

产生功率谱为高斯谱的瑞利杂波

% 高斯谱瑞利杂波
function y=ruiliclutter(azi_num,sigmac)
if nargin==0
 azi_num=2000;           %取样点数
  sigmac=1.2;            %杂波的标准差 即杂波的功率
end
fr=1000;                 %重复频率？
lamda0=0.005;            %波长？
sigmav=1.0;              %？？？？？
sigmaf=2*sigmav/lamda0; 
rand('state',sum(100*clock)); 
d1=rand(1,azi_num); 
rand('state',7*sum(100*clock)+3); 
d2=rand(1,azi_num); 
xi=2*sqrt(-2*log(d1)).*cos(2*pi*d2); 
xq=2*sqrt(-2*log(d1)).*sin(2*pi*d2); 
coe_num=12;     
for n=0:coe_num 
    coeff(n+1)=2*sigmaf*sqrt(pi)*exp(-4*sigmaf^2*pi^2*n^2/fr^2)/fr; 
end   
for n=1:2*coe_num+1 
    if n<=coe_num+1 
        b(n)=1/2*coeff(coe_num+2-n); 
    else 
         b(n)=1/2*coeff(n-coe_num); 
     end 
 end 
%生成高斯谱杂波 
    xxi=conv(b,xi); 
    xxq=conv(b,xq); 
xxi=xxi(coe_num*2+1:azi_num+coe_num*2); 
xxq=xxq(coe_num*2+1:azi_num+coe_num*2); 
xisigmac=std(xxi); 
ximuc=mean(xxi);
yyi=(xxi-ximuc)/xisigmac; 
xqsigmac=std(xxq);
xqmuc=mean(xxq); 
yyq=(xxq-xqmuc)/xqsigmac; 

yyi=sigmac*yyi;              %使瑞利分布杂; 
%yyq=sigmac*yyq; 
y=yyi;
 %figure,plot(real(y));  title('瑞利杂波时域波形,实部'); 
 %subplot(2,1,2),plot(imag(y));  title('瑞利杂波时城波形,虚部');
 %figure,psd(y);