On Fri, Dec 2, 2016 at 2:31 AM, Noel Chiappa <j...@mercury.lcs.mit.edu> wrote: > So I have this memory of a set of law promulgated by an engineer at DEC, one > of which was something to the effect that 'all digital circuits are made out > of analog devices'. However, my memory doesn't recall where I saw this, and my > Google-fu is not strong enough to turn it up. Can anyone help?
It's one of Don Vonada's laws. I am pretty sure I first read them in 'Computer Engineering', that book produced by DEC. I think the original is 'Digital circuits are made from analog parts' Another of the laws is 'There is no such thing as ground' which (a) means voltmeters have 2 leads, so you can take whatever you want as a reference and (b) all connections have impedance (the inductance is the important bit in general) so even if you have 2 points connected to a wire you call 'ground' they won't necessarily be at the same voltage all the time. A related one, which I don't know if it was ever written down in an official book (he told it to me in person) came from Professor M. V. Wilkes 'A digital circuit is like a tame animal. An analogue circuit is like a wild animal. Every so often the tame animal goes back to the wild' -tony -tony > > Noel
