A
two-state trajectory (also termed
two-state time trajectory or a
trajectory with two states) is a dynamical signal that fluctuates among two distinct values: ON & OFF, open & closed, , etc. Mathematically, the signal
![](http://info.babylon.com/onlinebox.cgi?rt=GetFile&uri=!!ARV6FUJ2JP&type=0&index=1829)
has, for every
![](http://info.babylon.com/onlinebox.cgi?rt=GetFile&uri=!!ARV6FUJ2JP&type=0&index=710)
either the value or .