I see it like this: -

[![enter image description here][1]][1]

Or you could make an argument that the bandwidth is \$\dfrac{\text{shorted time period}}{2}\$

In other words, if you do not calculate the time difference for every occurance of a start/stop situation, the values will have the possibility of being aliased.

Hence it is the frequency of your stop (or start) signal that determines your bandwidth.

  [1]: https://i.sstatic.net/nipLw.png