Feedback lab3 (part 2)

- Definition of propagation delay:

Not everybody got that right. It is defined on pages 40/41 in the compendium: "one measures the propagation
delay tp as the time it takes from when the switch is flipped until the output reaches the switching threshold Vsw of the next stage. ... Often the simplifying assumption is made that
Vsw = Vdd/2"

Some groups used the 'transition time' that is actually not discussed in the compendium and only relates to a single signal, i.e. not a relation between an input and an output. Other books define it as the time it takes a digital signal to go from 10% of its transition to 90% of its transition. But again: this is not relevant here.