why simulink has noise while ode45 dose not?

Hi friends

I have developed a code based on ode45 and a similar simulink. the similink scope shows some noise in the results while ode45 does not. why is there this difference and how can I eleminate the noise from the scope in simulink?

I have attached the figures

Answer 1

[rubindan]

Without code or Simulink model it is hard to tell what is exacly the reason. In case that the noise is numeric and should not be there, you probably need to change the solver settings in Simulink (Simhlintaion-->Model Cofigureation Parameters->Solver). Try, for e.g., reducing the tolerance.

[hossein]

thanks for the advice, actully reducing max and min of the step size solve the problem, while reducing the tolerance occures an error of singularity.

thanks alot dud.