How to create a noisy signal for wavelet transform practice?

I was trying the Wavelet toolbox; wherein they have the file 'noisysig.mat'. It contains three variables s1, s2 and x.

I understand that these contain the normal and the noisy signal but I wish to know how to create such noisy signals so that I can practice denoising with some other signals. How do I do that?

Answer 1

[Rafael Hernandez-Walls]

maybe this code will help you

N=1000;
x=linspace(0,2*pi,N);
y=sin(x);
y2=randn(1,N);
y3=y+y2*.1;
subplot(2,1,1);plot(x,y)
subplot(2,1,2);plot(x,y3)

[Sachin Motwani]

Thanks. It helps.