I’m pretty sure that that analog signals is just a continuous stream of input versus digital which provides signals at discrete time steps. Why have we shifted from analog to digital for so many things? Wouldn’t a steady stream of information be of better use?
In: Technology
Your summary understanding is pretty good. The big fundamental reason behind the shift is noise/error.
If you have an analog signal, and it gets distorted with noise, you don’t know what it was beforehand, the noise is carried all the way to the end. If each step, each wire, each filter introduces a tiny bit of error, you are both limited in the number of steps before noise overwhelms the signal, and need perfect, great quality components to process it with as little noise introduced as possible.
If you have a digital signal, where 0 is 0 volt, and 1 is +5 volt, if you get 1.1v of noise on the line, you still know upon arrival which one was 0, and which one meant 1, run that through a buffer / schmitt trigger (a special circuit that takes such “dirty” digital input, say, +0.8v and +4.4v, and scrubs it, producing clean 0v or +5v on output).
This way your only point where you lose quality is when you convert from analog to digital, once – afterwards your data remains unchanged and undamaged, no matter how many processing steps it undergoes, because every time it has a chance to go a little “dirty” it can be cleaned up. And if given step risks introducing noise so bad the data can’t be “cleaned”, you just send more data, so that whatever was lost can be reconstructed from redundant extras.
That means cheap, tiny components, because you don’t care about a bit of noise. That means arbitrary media, because in analog converting between electric current, light intensity, magnetic field, magnetization of recording tape and so on was always tricky, as they never converted completely 1:1. What your tape recorder got through the microphone and wrote to tape was never identical to what it read and replayed; similar, yes, but if silence was still silence and max volume was still max volume, the bass was a little more warbling, the really quiet parts were completely gone, and so on. With digital, a “1” is always a “1” and “0” is always a “0”; in particular “0.98” is still a “1” and “0.2” is still a “0”, you know the inaccuracies are an error, and you can reconstruct the original just as it was digitized, simply by discarding the error.
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