Abstraction is the original sin of technology. It's essential to do anything and we have taught two generations to treat abstractions as real, but not what's beneath the ones they use nor the implications of this lie, and we wonder why no one can see the impact the lie has on their work and world.
Nah, this is just a myth promoted by math departments to justify teaching diffyqs.
It's discrete logic and ADC's all the way down (No idea what the A stands for there).
The best analog circuit is a 50 Ohm antenna connector, a 1mm long stripline, to the pin of the chip that converts it into a pure and holy digital signal that means you no longer have to worry about accumulating noise.