noise generation
b=noisegen(pas,Tmax,sig)
generates a Scilab function [b]=Noise(t) where Noise(t) is a piecewise constant function ( constant on [k*pas,(k+1)*pas] ). The value on each constant interval are random values from i.i.d Gaussian variables of standard deviation sig. The function is constant for t<=0 and t>=Tmax.
noisegen(0.5,30,1.0);
x=-5:0.01:35;
y=`feval`_(x,Noise);
`plot`_(x,y);