Analog Is Digital? Seems like a perfectly reasonable question to me, and I can't see what is opinion based about it. It might be true that it may not have an accurate answer at the moment.

The idea of the question is representing an analog signal as a sum of impulse responses of the analog signal, such that the spacing between 2 impulses is infinitesimal.

It is a good question, what is opinion based about it?

  • \$\begingroup\$ Not a bad question since discrete time signals are usually introduced in (signals and systems) text books as being made up of Dirac impulses and the mathematics developed for continuous time signals are then carried over to the discrete time signals. (This, of course means "digital is analog" and not the other way around) The question has gathered a lot of answers also it seems. \$\endgroup\$
    – AJN
    Jul 3, 2021 at 16:56
  • \$\begingroup\$ @AJN if "digital is analog", why isn't analog digital? \$\endgroup\$ Jul 3, 2021 at 17:05
  • \$\begingroup\$ I have not given it enough thought; but if the relation is a subset type relation, (as mentioned in one of the answers/comments), then the relation need not be reflexive. A cat is an animal, but that doesn't meant that an animal is a cat. \$\endgroup\$
    – AJN
    Jul 3, 2021 at 17:09
  • \$\begingroup\$ I doubt if mathematicians would agree if a signal made from Dirac impulses spaced infinitesimally close is the same as a continuous signal (by their deifnition). I am not a mathematician; so I do not know. I do know that mathematicians deal with such objects (which have infinite amount of discontinuities in finite spacing) and I have not seen them deal with it as though they were continuous signals. So when they derive theorems, they specifically derive them for continuous time signals and signals with finite amount of discontinuities and ... \$\endgroup\$
    – AJN
    Jul 3, 2021 at 17:11
  • \$\begingroup\$ ... specifically exclude signals with infinite amount of discontinuities in finite intervals. So, in short, I think a mathematician (with knowledge in relevant area) would be able to clearly answer this question. \$\endgroup\$
    – AJN
    Jul 3, 2021 at 17:14
  • 1
    \$\begingroup\$ The question and whatever be the answer to it has nothing to do with designing on practice. Suppose I design an astable multivibrator and somebody argues that the output the oscillator is not Analog but Digital, or the otherway, I could LEAST care about it. As long as the design works as intended by the requirements, only that would matter in practice. \$\endgroup\$
    – Mitu Raj
    Jul 4, 2021 at 18:36

1 Answer 1


It's just a pointless philosophical question that has nothing to do with designing electronics and has absolutely no practical value. You even write in your own answer:

The question you ask is beyond electrical engineering and even beyond Physics. It falls into Metaphysics and philosophy.

The close reason is less important, but opinion based seems like the closest one. No one can answer this based on practical experience, other than possibly a quantum physicist with a minor in linguistics seeing how both analog and digital are highly overused.


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