3 ms·
Liar. You used NAND gates and a clock.
by IncreasePosts 2y ago
Liar. You used NAND gates and a clock.
- userbinator 2y ago...a clock which can be made from a ring oscillator, consisting of an odd number of NAND gates wired as NOT gates.
- ArchAndStarch 2y agoOh wow, I didn't actually know that. Thanks for the interesting trivia
- schoen 2y agoHow do we know that that will converge to a single constant period of oscillation? Could you have a few different-sized square waves continue to cycle through the circuit? (I've never built or simulated that, I'm just trying to imagine what could happen!)
- rational_indian 2y ago>Could you have a few different-sized square waves continue to cycle through the circuit? No.
- schoen 2y agoCould you help improve my intuition about that, or give me a reference where I could learn more?
- rational_indian 2y agoFirst look up Barkhausen criteria, then read the following. For ring oscillators gain will be greater than unity for only those waves whose period matches the gate delay. Only one such wave exists since the gate delay is a fixed number.
- userbinator 2y agoIt is possible for a ring oscillator to generate harmonics: https://ieeexplore.ieee.org/iel5/16/31849/01482193.pdf https://ieeexplore.ieee.org/iel5/16/31849/01482193.pdf
- rational_indian 2y agoInteresting, would have loved to read the paper. Unfortunately I don't have an IEEE subscription right now.
- IncreasePosts 2y agohttps://sci-hub.ru/10.1109/T-ED.1982.20696 https://sci-hub.ru/10.1109/T-ED.1982.20696
- rational_indian 2y agoOkay, so I was wrong. You can get multiple harmonics if you use a long enough chain of inverters. I will simplify the paper mentioned in a sibling comment. In a long chain at any given point of time certain (variable number of) pairs of inverters drop in and out of the circuit changing the total propagation delay, giving rise to multiple harmonics. You'll have to read the paper for details.