4 ms·
One interesting note re: 8b/10b encoding. The motivation in the article is accurate, but not the whole story (never is, in the analog world). Nowadays, 8b/10b
by twtw 8y ago
One interesting note re: 8b/10b encoding. The motivation in the article is accurate, but not the whole story (never is, in the analog world).
Nowadays, 8b/10b (or more realistically 128b/130b) is critical to enable clock recovery by making sure the signal transitions frequently enough.
> Computers can't count past 1
Reminds me of this excellent quote: "Every idiot can count to one" - Bob Widlar
- pjc50 8y agoYeah, that section is a little ropey; the real way to think of high-speed networking systems is not that they send levels but that they send edges. Levels can drift around all over the place, and in a fast system the level at one end is not the same as the level at the other. This line of thinking makes clearer what signal reflections are and why they are a problem, and what the role of eye diagrams is.
- vvanders 8y agoThe Art of Electronics[1] has a fantastic section on differential signaling and common mode voltage. That book is a treasure even today despite being published initially in 1980. [1] https://en.wikipedia.org/wiki/The_Art_of_Electronics https://en.wikipedia.org/wiki/The_Art_of_Electronics
- dublin 8y agoOddly, nothing has changed in the way God made the universe in the intervening years. Some things are timeless.