wk1.m

三元阵的信号相位匹配法,结合相位匹配法的公式就能很好的理解其仿真原理

>> format long
>> Fs=10000;
>> t=0:1/Fs:1+2/Fs;
>> s_3=square(2*pi*t*800);
>> for a=1:1+Fs
    s3(a)=s_3(a);

end
>> for a=1:1+Fs
    s2(a)=s_3(a+1);
end
>> for a=1:1+Fs
    s1(a)=s_3(a+2);
end
>> t=0:1/Fs:1;
>> subplot(3,2,1)
>> plot(t,s1),axis([0 0.025 -1.5 1.5]);
>> n=randn(size(t));
>> k1=sqrt(10^7*sum(abs(s1).^2)/sum(abs(n).^2));
>> n1=k1*n;
>> p1=s1+n1;
>> P1=s1+n1;
>> P1=s1+n1;
>> P1=fft(p1);
>> N1=fft(n1);
>> subplot(3,2,3)
>> plot(t,p1),axis([0 0.025 -6000 6000]);
>> subplot(3,2,2)
>> [S,f]=pwelch(s1,[],[],1024,Fs);
>> plot(f,S)
>> subplot(3,2,4)
>> [Pxx1,f]=pwelch(p1,[],[],1024,Fs);
>> plot(f,Pxx1)
>> n=randn(size(t));
>> k2=sqrt(10^7*sum(abs(s2).^2)/sum(abs(n).^2));
>> n2=k2*n;
>> p2=s2+n2;
>> P2=fft(p2);
>> N2=fft(n2);
>> n=randn(size(t));
>> k3=sqrt(10^7*sum(abs(s3).^2)/sum(abs(n).^2));
>> n3=k3*n;
>> p3=s3+n3;
>> P3=fft(p3);
>> N3=fft(n3);
>> w=(1:length(P1))*2*pi/length(P1);
>> A=real(P3).*sin(2*w)+imag(P3).*cos(2*w)-imag(P1);
>> B=real(P2).*sin(w)+imag(P2).*cos(w)-imag(P1);
>> C=real(P2).*cos(w)-imag(P2).*sin(w)-real(P1);
>> D=real(P3).*cos(2*w)-imag(P3).*sin(2*w)-real(P1);
>> Res=((abs(P2).^2-abs(P1).^2-abs(N2).^2+abs(N1).^2).*A-(abs(P3).^2-abs(P1).^2-abs(N3).^2+abs(N1).^2).*B)./(2*(C.*A-D.*B));
>> Ims=((abs(P3).^2-abs(P1).^2-abs(N3).^2+abs(N1).^2).*C-(abs(P2).^2-abs(P1).^2-abs(N2).^2+abs(N1).^2).*D)./(2*(C.*A-D.*B));
>> sout=ifft(Res+i*Ims);
>> subplot(3,2,5)
>> plot(t,real(sout)),axis([0 0.025 -1.5 1.5]);
>> subplot(3,2,6)
[Sxx,f]=pwelch(real(sout),[],[],1024,Fs);
plot(f,Sxx)