9 ms·

> Does anyone really want to process analog data? I mean... maybe we should? All radio waves, such as 802.11, are fundamentally analog data. And then they are

> Does anyone really want to process analog data? I mean... maybe we should? All radio waves, such as 802.11, are fundamentally analog data. And then they are converted back into digital with incredible QAM-encoding levels. If you think QLC 4-bits per Flash-cell is big, wait till you see 256-QAM (aka: 8-bits per 802.11 timeslice), or more. I believe I saw some spec for some fiber-optic cable that is 32768-QAM (aka: 15-bits per timeslice). -------- Then again, Flash (and other memory) are composed of individual cells. True-analog signals like radio-waves are truly analog, so maybe its not quite the same. But maybe we should think of things like tape or hard-drives as an analog signal. Or maybe not, who knows? I'm not actually a storage specialist so I don't really know. (Nor am I really in communications, lol).

foobiekr 3y ago
256+ QAM is there but you will almost never see it in practice unless you’re next to the AP. Wifi7 defines up to 4096 so maybe the economics will drive improvements that didn’t land in 6E APs.
- tguvot 3y ago
  docsis. up to 16384
- Taniwha 3y ago
  You'll see it on almost every cableTV channel these days
  - foobiekr 3y ago
    I was referring to Wifi but yes
enkid 3y ago
I'm pretty sure that Einstein proved that light (including radio) is not, in-fact, analog, but rather has discrete levels of energy in quantum steps.
- tlb 3y ago
  That turns out not to matter, because the noise is always at least several quanta at whatever frequency you’re using so you can’t get close to the quantization limit anyway.
  - chrisweekly 3y ago
    Also our physiological sensory and processing equipment (ie, eyes, ears, brain...) translates analog / continuous input into discrete electrical signals; a given neuron fires or doesn't.
    - kstrauser 3y ago
      That’s not how that works.
- urinotherapist 3y ago
  Light is produced and consumed in quanta (photons) by reguar matter. Light itself is just radio wave. Radiowave has not such limitation. It's limitation of atomic particles.
  - simiones 3y ago
    That's not how quantum mechanics works. Radio waves are photons, and photons are radio waves. Different experiments will reveal different aspects of it, but these are not separate phenomena. Also, the exact same thing is true of every other particle: just as photons are quantizations of the electro-magnetic waves, electrons are quantizations of waves in the electron field, quarks are quantized waves in the quark field etc. Atoms and molecules are also waves; in fact, there have been experiments showing the wave-like nature of molecules with something like 5000 atoms.
    - urinotherapist 3y ago
      I saw water-like behavior of a wave! I have no idea, how much molecules it contains, large waves have many cubic meters of water, but I'm pretty sure that quantum behavior is not limited to 5000 atoms. Waves, even very large onses, are moving energy in "packets". 1 wave - 1 quanta. So, what? Photon is radio-wave (EM-wave). Typical photon is produced and consumed by a electron, so properties of photon produced by an electron are limited by the electron, also, our abilty to detect photonare limited by the electron. However, EM-waves in general are not limited by electron. On smaller scale, electron interacts with other charged particles and with EM-field (the medium) via EM-waves. I'm pretty sure that electron is not staying stil, it's vibrating because of thermal noise. Vibration of charged particle produces EM-waves. Those EM-waves are not photons.
analog31 3y ago
"Analog" and "digital" do not refer to the physical process of transmission, such as radio waves, but the interpretation of the signal. A digital system has rules for forming and interpreting the signal, so that the transmitted and received messages are identical. These rules typically involve things like signal level thresholds and timing. Well-engineered systems have "noise immunity" meaning that the thresholds are well above the noise floor, making the likelihood of an error negligible. If you hang an oscilloscope probe on a "digital" signal, such as the data lines on a memory chip, it might look like a frightening mess, but so long as the rules are obeyed, data transfer occurs faithfully. In a true analog medium, there's no way that the receiver can make out precisely what was sent, and two receivers will get different information.
- TylerE 3y ago
  All mediums are ultimately analog.
- freedude 3y ago
  "Well-engineered systems have "noise immunity" meaning that the thresholds are well above the noise floor, making the likelihood of an error negligible." Well-engineered systems also expect noise and compensate with error detection/correction.
muxator 3y ago
256-QAM encodes 4 bits on the "phase" component and 4 on the quadrature one. They can be regarded as independent signals. Think about a sin() and a cos() being orthogonal to each other even for the same frequency.

foobiekr 3y ago

256+ QAM is there but you will almost never see it in practice unless you’re next to the AP. Wifi7 defines up to 4096 so maybe the economics will drive improvements that didn’t land in 6E APs.

tguvot 3y ago
docsis. up to 16384
Taniwha 3y ago
You'll see it on almost every cableTV channel these days
- foobiekr 3y ago
  I was referring to Wifi but yes

enkid 3y ago

I'm pretty sure that Einstein proved that light (including radio) is not, in-fact, analog, but rather has discrete levels of energy in quantum steps.

tlb 3y ago
That turns out not to matter, because the noise is always at least several quanta at whatever frequency you’re using so you can’t get close to the quantization limit anyway.
- chrisweekly 3y ago
  Also our physiological sensory and processing equipment (ie, eyes, ears, brain...) translates analog / continuous input into discrete electrical signals; a given neuron fires or doesn't.
  - kstrauser 3y ago
    That’s not how that works.
urinotherapist 3y ago
Light is produced and consumed in quanta (photons) by reguar matter. Light itself is just radio wave. Radiowave has not such limitation. It's limitation of atomic particles.
- simiones 3y ago
  That's not how quantum mechanics works. Radio waves are photons, and photons are radio waves. Different experiments will reveal different aspects of it, but these are not separate phenomena. Also, the exact same thing is true of every other particle: just as photons are quantizations of the electro-magnetic waves, electrons are quantizations of waves in the electron field, quarks are quantized waves in the quark field etc. Atoms and molecules are also waves; in fact, there have been experiments showing the wave-like nature of molecules with something like 5000 atoms.
  - urinotherapist 3y ago
    I saw water-like behavior of a wave! I have no idea, how much molecules it contains, large waves have many cubic meters of water, but I'm pretty sure that quantum behavior is not limited to 5000 atoms. Waves, even very large onses, are moving energy in "packets". 1 wave - 1 quanta. So, what? Photon is radio-wave (EM-wave). Typical photon is produced and consumed by a electron, so properties of photon produced by an electron are limited by the electron, also, our abilty to detect photonare limited by the electron. However, EM-waves in general are not limited by electron. On smaller scale, electron interacts with other charged particles and with EM-field (the medium) via EM-waves. I'm pretty sure that electron is not staying stil, it's vibrating because of thermal noise. Vibration of charged particle produces EM-waves. Those EM-waves are not photons.

analog31 3y ago

"Analog" and "digital" do not refer to the physical process of transmission, such as radio waves, but the interpretation of the signal. A digital system has rules for forming and interpreting the signal, so that the transmitted and received messages are identical. These rules typically involve things like signal level thresholds and timing. Well-engineered systems have "noise immunity" meaning that the thresholds are well above the noise floor, making the likelihood of an error negligible. If you hang an oscilloscope probe on a "digital" signal, such as the data lines on a memory chip, it might look like a frightening mess, but so long as the rules are obeyed, data transfer occurs faithfully. In a true analog medium, there's no way that the receiver can make out precisely what was sent, and two receivers will get different information.

TylerE 3y ago
All mediums are ultimately analog.
freedude 3y ago
"Well-engineered systems have "noise immunity" meaning that the thresholds are well above the noise floor, making the likelihood of an error negligible." Well-engineered systems also expect noise and compensate with error detection/correction.

muxator 3y ago

256-QAM encodes 4 bits on the "phase" component and 4 on the quadrature one. They can be regarded as independent signals. Think about a sin() and a cos() being orthogonal to each other even for the same frequency.