Negative widths and offsets


I’m just looking for a slight clarification of the meaning of negative offsets and widths. As for offset, the help file says “The offset from a rising clock edge to a glitch pulse rising edge, as a percentage of one period.” Would negative offset correspond to the second half of the clock cycle, meaning when the clock signal is low?

As for negative widths, the help file says “Note that negative widths are allowed; these act as if they are positive widths on the other half of the clock cycle.” So what happens when if you have a positive offset but a negative width? Does it mean that if I want to insert a glitch during the second half of the clock cycle, both width and offset need to be negative?


In the above image, offset moves the rising edge of #1 relative to clk_src and width moves the falling edge relative to the rising edge. A negative width will move the width edge behind the offset edge, making the width edge rising and the offset edge falling. I’d recommend ignoring negative widths as you can recreate the same glitch by reducing your offset.

A negative offset value will put the glitch on the negative half of the clock cycle.

Ah, now I see. Thank you very much! Very clarifying.