I have attended such HV presentations (at about half the voltage 😀) in this excellent museum a few times when I was young.
The sound of the spark and the smell (from the generated ozone) remain in my memory
https://www.youtube.com/watch?v=FmHFyLsagTo
Deutsches Museum: High voltage plant
George
I don't know what the HD-SDI video waveform looks like, but at some point it's all sine waves. The great, and expensive, thing about SDI video is the automatic EQ at the receiving end. This allows cable runs with a good bit of HF attenuation to still work. It's often called reclocking the signal, but mostly it's just EQ to restore the signal edges.
It could be a QAM (Quadrature Amplitude Modulation). That's how cable companies do it.
Two sine waves at 90 degree apart. The amplitude and phase is makes a symbol which represents one byte in a 256 QAM. There is one symbol for each byte of 256 bytes. The digital video and audio is modulates the QAM and then is demodulated at receiving end.
Good learning moment because I was unaware of the details of this technology. You are a good teach because my brain reassembled your words in an immediate understanding of the core of it.
On a more general note: I am from the time that it was taught that twisted pair would be limited to 4kHz or thereabouts. With solid theoretical underpinning. We all know where that went with DSL. The thing that was overlooked in the old thinking was the power of 'synchronized logic', by lack of a beter word. This is another fine example of it.
Probably there is whole science behind it unbeknown to me, so my ill-informed question is: can a theoretical limit be applied to this principle?
I'm not clear about you question. "can a theoretical limit be applied to this principle."
Which principle? QAM? or DSL?
DSL has already reached it's limit. That's why the telco companies are laying out fiber everywhere. Desperately trying to catch up to cable companies' bandwidth.
QAM is limited to the total number of data symbols by noise. As more data symbols are used the symbols have to be space closer together and this makes the modulation more sensitive to noise. So I would say the limit then is the transmission system noise.
In a coax cable plant the noise rises with number of equipment on the plant including amplifier, modems, set top boxes, and docsis phone modems etc. The way to beat the noise is to break the systems down into smaller groups. The choice is fiber to the home, very expensive, or HFC, (Fiber Coax Hybrid). The latter is what we are doing because it utilized the existing coax plant and we are still ahead of the telco competition.
Fiber nodes are placed in the neighborhood and coax is run from there.
I'm not sure if this comes even close to answering your question.
Hi David,
Respectfully. Don't count the telco's out. I'm sitting with 50 meg download, direct and not shared. I'm with Bell Canada running on a bonded pair of lines. BTW, voice quality is as good as T1 / PRI and when the power is out, my phone still rings.
The next step in bandwidth for me is a fibre direct into my home. I also do not have grounding problems that cable installations do bring with them. Then, there is the amount of damage due to lightning strikes that aren't direct. Cable users suffer far worse damage than any other technology. This from over 35 years of direct observation and dealing with insurance companies. The main culprit for this damage is the cable's coax ground that will differ from the ground potential by thousands of volts and almost unlimited current looking for paths to equalize. Anything between cable ground and earth ground rates as an easy path. That includes speaker wires running close to ventilation covers in a home.
I won't allow cable in my home, not unless it's a fibre that is delivering my services. But then, it's no longer cable .. is it?
-Chris
Respectfully. Don't count the telco's out. I'm sitting with 50 meg download, direct and not shared. I'm with Bell Canada running on a bonded pair of lines. BTW, voice quality is as good as T1 / PRI and when the power is out, my phone still rings.
The next step in bandwidth for me is a fibre direct into my home. I also do not have grounding problems that cable installations do bring with them. Then, there is the amount of damage due to lightning strikes that aren't direct. Cable users suffer far worse damage than any other technology. This from over 35 years of direct observation and dealing with insurance companies. The main culprit for this damage is the cable's coax ground that will differ from the ground potential by thousands of volts and almost unlimited current looking for paths to equalize. Anything between cable ground and earth ground rates as an easy path. That includes speaker wires running close to ventilation covers in a home.
I won't allow cable in my home, not unless it's a fibre that is delivering my services. But then, it's no longer cable .. is it?
-Chris
The problem with cable burn is because the installer neglected to ground the cable at the house. It is standard now to use the same ground as hydro or whatever your power authority calls it. The cable on the strand is at the same potential of the strand on the pole which is the same ground as telco. So if the telco company doesn't maintain the strand ground then the cable loses it too.
If the cable is grounded with your power ground on you house you won't the get the audio hum and hum bar on your TV.
We are offing our customers 150 mbps right now. It could be higher but no one is interested. Maybe cable sucks were you are but not everywhere.
These things needn't happen and don't in my system. Of course I'm the guy maintaining it.
And by the way fiber has a static shield in it under the jacket which is grounded to the strand.
If the cable is grounded with your power ground on you house you won't the get the audio hum and hum bar on your TV.
We are offing our customers 150 mbps right now. It could be higher but no one is interested. Maybe cable sucks were you are but not everywhere.
These things needn't happen and don't in my system. Of course I'm the guy maintaining it.
And by the way fiber has a static shield in it under the jacket which is grounded to the strand.
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The SDI signal is typical of high speed serial data transmission. its also done on twisted pair. We are now getting as standard consumer practice 6 Gbps over a twisted pair in HDMI and up to 18 feet passive (no active equalizer). This is 18 Gbps for an HDMI link. I'm told the next gen of HDMI will be 33 Gbps. or around 8-9 Gbps per lane. These are pretty amazing data rates for inexpensive consumer products. But needed for 4K TV. The 33 Gbps will be for 8K TV.
8K?
These speeds are possible over short distances but for long I think it will require fiber.
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Yeah I saw that. I was wondering how they keep the sideways wow and flutter under control?
Jan
It seems that the push does not make it move sideways, which is very good. It does wiggle but that's the same as a warped record. All in all looks quite well done, no?
Jan
Jan
Jan, you got all the gear to test it, looking forward to the results. The only remaining problem is to get a prototype on loan.
We covered this in another thread. There is a live demo so it is not fake but if you are at all hands on familiar with any of the maglev gadgets/toys the damping in any one direction is poor and you can see that in the demo. Now imagine we now have to constrain the system in all 6 degrees of freedom, i.e. a bearing that has no stiffness in any direction. Also there are no demos I could find of actual music being played.
With a real LP tracking force will excite motion in all directions.
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