fibre optic line petition sign all

[Steve]

An instantaneous change in the amplitude of a signal must comprise of an infinite number of cos waves; one at every frequency, basically.

So going from -5V to 5V instantly is a no no in terms of sending signals over a piece of copper. It's fine on a motherboard where that copper track is used for just one signal (although chances are not all those will be square-wave by virtue of the data rate's they're trying to achieve), but down a phone line, or over any other form of communications link, you don't want a transition like that because it consumes pretty much the entire frequency spectrum.

I should also add that you can fit a lot of binary onto a communications channel, but it doesn't take the form of a square-wave; it'll be a more "shapely" wave with the 1s and 0s defined by one of a few other means. Chances are you might turn a short sequence of binary into a single "symbol" and transmit that... that's what they do for Freeview, Satellite and various other things.

[jamin]

An instantaneous change in the amplitude of a signal must comprise of an infinite number of cos waves; one at every frequency, basically.

So going from -5V to 5V instantly is a no no in terms of sending signals over a piece of copper. It's fine on a motherboard where that copper track is used for just one signal (although chances are not all those will be square-wave by virtue of the data rate's they're trying to achieve), but down a phone line, or over any other form of communications link, you don't want a transition like that because it consumes pretty much the entire frequency spectrum.

Ah, I see what you are sayin' mate. Couldn't quite see from your former post what you meant.

[badass]

Technically it can, electrons are what bond everything together, when a metal corrodes it 'snaps' an outer electron of the oxidising atom into it's own nucleonic bond, the far lone outer electron of copper is what makes it such a great conductor and lets it flow along. My point originally being, the copper isn't where the 'lost' electrons go.

Never heard of a Nucleonic bond. Is this something thats dealt with at degree level only?

[aidanjt]

It's the physical force that locks particles together. But that's not really applicable, my intention was to demonstrate that the electrons are leaked elsewhere rather than the physical structure of the copper, i.e. the surrounding environment, the likely path ultimately being earth.

[TiG]

http://www.theregister.co.uk/2007/05...mics_of_fibre/

Why didn't this come out a week or so ago hey

Figures for our little discussion.

TiG

[aidanjt]

Wow, that's a really good, well written article, makes a change for theregister :/

[TiG]

Yep not often i find myself quoting the register but that looks well thought out and reasoned and backed up with some actual reports.

Certainly interesting thoughts on it all.

TiG