%noise
noise=a+(b-a)*rand(4,1000)
a=4,b=11;
n=4+7*rand(4,1000)
subplot(2,2,1),plot(noise(1,:));
grid on;
xlabel('n1');
ylabel('noise1');
title('average noise 1');
subplot(2,2,2);plot(noise(2,:));
grid on;
xlabel('n2');
ylabel('noise2');
title('average noise 2');
subplot(2,2,3);plot(noise(3,:));
grid on;
xlabel('n3');
ylabel('noise3');
title('average noise 3');
subplot(2,2,4);plot(noise(4,:));
grid on;
xlabel('n4');
ylabel('noise4');
title('average noise 4');
