overlapping of tSU/tH

Interestingly, just as I posted the thread I re-examined the issue and it turned out to be my mis-interpretation of definitions. It is quite easy to misunderstand when things are not the "norm".

It is not physical overlap but an overlap by definition (man-made).

I am used to imagine the timing window shifting but never draw arrows from clk edge to both edges of the window.

If we draw arrows, then it looks overlpped whenever the window crosses past the clk edge.

It is been helpful anyway.