| Electronics > Beginners |
| Why binary is represented by two bits 0 and 1 and not three bits? |
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| tip.can19:
Thank you! This is really good. |
| IDEngineer:
A snarky answer to the question in the subject line is "Because the prefix 'bi' means 'two' and not 'three'". In addition to the other answers given, there's this: A binary (two state) system is inherently more noise resistant. You can tolerate a lot of noise when there are only two valid signal levels. As you add more "legal" levels, noise is more likely to create false transitions. The end game of that is, of course, pure analog which has an infinite number of valid signal "levels" but is always, in every real-world system, plagued by some amount of noise. And while in an analog signal chain noise errors accumulate, a digital system with discrete levels can reproduce an original signal with zero degradation. In fact, a digital system can actually remove noise from a noisy signal (think Schmitt Triggers, to say nothing of error detecting and correcting encodation). All of these features are enhanced by having just two legitimate signal levels. |
| tggzzz:
--- Quote from: IDEngineer on October 26, 2019, 06:09:39 am ---A snarky answer to the question in the subject line is "Because the prefix 'bi' means 'two' and not 'three'". In addition to the other answers given, there's this: A binary (two state) system is inherently more noise resistant. You can tolerate a lot of noise when there are only two valid signal levels. As you add more "legal" levels, noise is more likely to create false transitions. The end game of that is, of course, pure analog which has an infinite number of valid signal "levels" but is always, in every real-world system, plagued by some amount of noise. And while in an analog signal chain noise errors accumulate, a digital system with discrete levels can reproduce an original signal with zero degradation. In fact, a digital system can actually remove noise from a noisy signal (think Schmitt Triggers, to say nothing of error detecting and correcting encodation). All of these features are enhanced by having just two legitimate signal levels. --- End quote --- And with that we are getting closer to the fundamentals :) Next step is to understand and apply Shannon's theorem. N.B. Shannon's theorem isn't the be-all and end-all consideration; sometimes implementation technology characteristics are more important. But as the implementation technologies are refined over time, there is a tendency to approach the limits defined by Shannon's theorem. |
| MosherIV:
I like to explain from a different perspective. Yes, the answer is that it is easier to represent values with simple switch on or off. This was driven by the technology of the day. The very first computers were build with valves. It is difficult to get them to store an 'analogue' or voltage but it was easy to get them to store an on or off. So early computers developed binary computer system and the development carried on from there. This is also true for transistors. At the time of the first computers people did try different configurations. There is a true decimal computer, the Harwell Deckatron, which has true decimal memory - using decktron tube as memory. |
| radiolistener:
--- Quote from: tip.can19 on October 25, 2019, 08:51:34 am ---Why binary is represented by two bits 0 and 1 and not three bits? --- End quote --- Binary digit is represented by one bit. Not two. :) |
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