Add measurement noise

[Ji Chen]

Dear all,
   Measurement noise is simulated as independent zero-mean Gaussian with 
standard deviation per real component 0.01 and 0.02 for voltages and currents, 
respec-
tively. Ir and Vr are real parts of I and V respectively. 
    I'm not sure if the following codes are right. And how to deal with the 
imaginary componets?


Ir=Ir+0.02.*randn(length(Ir),1);
Vr=Vr+0.01.*randn(length(Vr),1);