Difference between step,ramp and Impulse response
Like the impulse response, the step and ramp responses describe an LTI-system. There are situations when the step response or the ramp response describe what we want to know about the system more directly than the impulse response. When the input to a system is a piece-wise constant function of time, the transitions are well described by the step response. It gives quite directly information about overshoot and settling time.