title: When(why) to use step/pulse/ramp functions in simulink?
body: <p>Hello guys I'd like to know the answer to the question that is the titled named by.</p>
  
  <p>For example if I have physical system described in differential equation(s), how should I know when I should use step, pulse or ramp generator? </p>
  
  <p>What exactly does it do? 
  Thank you for your answers.</p>