  In this paper, we introduce a new representation for open-loop reset systems.
We show that at steady-state a reset integrator can be modelled as a parallel
interconnection of the base-linear system and piece-wise constant nonlinearity.
For sinusoidal input signals, this nonlinearity takes a form of a square wave.
Subsequently, we show how the behaviour of a general open-loop reset system is
related to the nonlinearity of a reset integrator. The proposed approach
simplifies the analysis of reset elements in the frequency domain and provides
new insights into the behaviour of reset control systems.
