fnoise.m

matlab例子

n=[0:0.1:20]';
white=randn(1,length(n));
subplot(2,2,1); plot(n,white);
xlabel('t/ms');ylabel('w(n) v');title('白噪声');
grid;
num=1; den=[0.1,1];
figure(1);
fn=lsim(num,den,white,n);
%subplot(2,2,2); plot(n,fn);
%grid;
for i=1:9
   fn=lsim(num,den,fn,n);
end
figure(2);
subplot(2,2,1); plot(n,fn);
xlabel('t/ms');ylabel('f(n)/v');title('1/f噪声(n=10,RC=0.1)');
grid;
nf=[0:200];
[f2,nf2]=sigfold(fn,nf);
[rff,nrff]=conv_m(fn,nf,f2,nf2);
%rfp=rff(201:400);
%nrfp=nrff(201:400);
%subplot(2,2,3); plot(nrfp/10,rfp);
subplot(2,2,2); plot(nrff/10,rff);
xlabel('t/ms');ylabel('rff(n)');title('自相关(n=10,RC=0.1)');
grid;
k=0:100;w=(pi/100)*k;
%X=x*(exp(-j*pi/500)).^(n'*k);
X=rff'*(exp(-j*pi/100)).^(nrff'*k);
magX=abs(X);
subplot(2,2,3); plot(w/pi,magX);
xlabel('pi');ylabel('S(w)');title('功率谱(n=10,RC=0.1)');
grid;
for i=1:10
   fn=lsim(num,den,fn,n);
end
figure(3);
subplot(2,2,1); plot(n,fn);
xlabel('t/ms');ylabel('f(n)/v');title('1/f噪声(n=20,RC=0.1)');
grid;
nf=[0:200];
[f2,nf2]=sigfold(fn,nf);
[rff,nrff]=conv_m(fn,nf,f2,nf2);
%rfp=rff(201:400);
%nrfp=nrff(201:400);
subplot(2,2,2); plot(nrff/10,rff);
xlabel('t/ms');ylabel('rff(n)');title('自相关(n=20,RC=0.1)');
grid;
X=rff'*(exp(-j*pi/100)).^(nrff'*k);
magX=abs(X);
subplot(2,2,3); plot(w/pi,magX);
xlabel('pi');ylabel('S(w)');title('功率谱(n=20,RC=0.1)');
grid;

%------------------RC=0.5
den=[0.5,1];
fn=lsim(num,den,white,n);
for i=1:9
   fn=lsim(num,den,fn,n);
end
figure(4);
subplot(2,2,1); plot(n,fn);
xlabel('t/ms');ylabel('f(n)/v');title('1/f噪声(n=10,RC=0.5)');
grid;
nf=[0:200];
[f2,nf2]=sigfold(fn,nf);
[rff,nrff]=conv_m(fn,nf,f2,nf2);
%rfp=rff(201:400);
%nrfp=nrff(201:400);
subplot(2,2,2); plot(nrff/10,rff);
xlabel('t/ms');ylabel('rff(n)');title('自相关(n=10,RC=0.5)');
grid;
X=rff'*(exp(-j*pi/100)).^(nrff'*k);
magX=abs(X);
subplot(2,2,3); plot(w/pi,magX);
xlabel('pi');ylabel('S(w)');title('功率谱(n=10,RC=0.5)');
grid;
fn=lsim(num,den,white,n);
for i=1:10
   fn=lsim(num,den,fn,n);
end
figure(5);
subplot(2,2,1); plot(n,fn);
xlabel('t/ms');ylabel('f(n)/v');title('1/f噪声(n=20,RC=0.5)');
grid;
nf=[0:200];
[f2,nf2]=sigfold(fn,nf);
[rff,nrff]=conv_m(fn,nf,f2,nf2);
%rfp=rff(201:400);
%nrfp=nrff(201:400);
subplot(2,2,2); plot(nrff/10,rff);
xlabel('t/ms');ylabel('rff(n)');title('自相关(n=20,RC=0.5)');
grid;
X=rff'*(exp(-j*pi/100)).^(nrff'*k);
magX=abs(X);
subplot(2,2,3); plot(w/pi,magX);
xlabel('pi');ylabel('S(w)');title('功率谱(n=10,RC=0.5)');
grid;