3 ms·
That's more protocol than anything. The IR used day-to-day was designed for consumer products in the 70s and 80s, so by necessity was a very simple protocol. T
by Sanddancer 11y ago
That's more protocol than anything. The IR used day-to-day was designed for consumer products in the 70s and 80s, so by necessity was a very simple protocol. There's no physical limitation for higher bandwidth IR.
- analognoise 11y agoAs I understand https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampli... IR has a frequency of between 430THz and 300GHz, so Max bandwidth would be between 215Tsymbols and 150Gsymbols (I used symbols instead of bits because I forgot the right term...) So there is an information-theory limit, as I understand it. If I was ever wrong, this is the right crowd to find the person who will correct me!
- Sanddancer 11y agoYeah, there is the Shannon Limit which gives the theoretical max, I was more trying to get at there not being a reason why we'd be stuck at remote control/irda speeds.
- hamiltonkibbe 11y agoIR comma doesn't the frequwncy of the light as a carrier, it uses pulsed IR (on=1 off=0 usually in the KHz range) the limitation is usually the rise time of the LEDs
- analognoise 11y agoYeah, but I wondered what the absolute upper limit would be. Good point about the rise time of the LEDs though.
- Someone 11y agoSymbols/second = baud (https://en.m.wikipedia.org/wiki/Baud https://en.m.wikipedia.org/wiki/Baud) And, ignoring other physical or 'current technology' limits, you can put as many bits in each symbol as you like.
- analognoise 11y agoThank you! Can't believe I couldn't remember that word, although I never really understood why you can put as many bits in each symbol as you like - it seems like that would just mean stuff an infinite number of bits into each one? (Obviously silly, but then why is it defined that way?) - Great, now I have to read about that this morning. :)