Here&#x27;s another. Imagine you want the ratio of two clock sources. Put them both through frequency dividers, with one divider output put through a phase shifter. compare the resultant divided frequencies by xoring the signals together. The ratio of the frequencies is given by the ratio of the dividers when you can find a phase shift such that the xor output doesn&#x27;t change. The time you wait to see if the xor output doesn&#x27;t change represents the certainty you have in your ratio. This is called the time frequency uncertainty relation, also known as the Heisenberg uncertainty principle.