If you put a comparator loop like in the picture and power it with a lever it will slowly loose its power.
When it lost all its power it will start from the beginning.
It should just stay as the first picture.

This may be duo to how comparators work. I'm asuming that they will put the strange their repeating in front of them and therefore overwriting the strength that is allready there. It should check if the strength of the redstone signal is greater then the one he's emitting (sry for misstakes)