Again with more science-oriented questions.
A frequency is an amount of times per second "something happens". Light pluses, hammers hitting a plate, heart beating, whatever.
yeh I have an idea about frequency in electrical engineering ...
A wire (any metal wire) can carry pulses of electrical current. A pulse of electrical current can be used to transmit information, have you ever heard of Morse Code? It's much much more basic than what a computer does, but the principle is the same.
yeh I read about it .. but I did not get how the receiver and what the receiver receives . the principle of sending is clear that is uses pre=defined codes ( dots , dashes and spaces ) depending on the time a button is being pressed or the switch is close . once switch is closed charge flows and induces magnetic field which interacts with other elements and drops a pen down to write or line a line .
I don't know how the codes could be carried away long distances and how the receiver receives !
The frequency of this pulses through the cable, or how much pulses you can send through it per second, is high but has a upper limit.
The upper limit is the speed of the pulse in the medium. Electrical current is movement of electrons inside the metal. They travel at a set speed, so if you send pulses at a too high frequency some of the pulses simply overlap because there is not enough time for the pulse to travel in the wire before another pulse is applied to it.
good I got it ... electron moves at 2000Km per second around the nucli
I don't know if this is absolute or limited to this scenario
Let's imagine a firearm shooting once. Bang!
Now increasing the frequency of the shooting, basically shooting faster, the silence between each shot shortens, and when you are firing dozens or even hundreds of bullets per second (as any self-respecting machine-gun) you just hear a single very loud buzzing until you stop firing.
I think this example works well in the torch experiment where the observer of the outgoing beam is human which at high speeds or frequency of beam .. is interrupted and unable to differentiate , but as far as digital CRKTs - instead of human eye - are concerned they can differentiate because verily there is an inbetween interval of time though less that one tenth fraction of a second .
The same happens inside your cable. It's no more pulses, it's continuous current. Which is good for powering a device, but it's useless for carrying information. To read the information they carry, you need to receive each pulse separated from the one before and the one after it.
Like it was Morse Code. You need to be able to tell the difference between dots and lines, or you are wasting your time.
it is continuous stream of electrons if there is no separation between ... human observation of the separation could proof but couldn't deny because human eye dosent catch if frequency is very high .
Another issue with using a simple metal wire like twisted wire is interference. That is basically stuff outside the cable that generate fake pulses or degrade the pulses you are sending through.
How can that happen? Physics. Electric current (electron movement) generates magnetic fields and changing (or moving) magnetic fields generate current (electron movement). It's the
electromagnetism.
So if that cable travels near anything carrying current, it will receive interference, that degrades its ability to carry information.
is the interference internal or external ? I thought it is internal because the wire loop pattern forces wires to run side by side till a single wire reaches a home ... thus the voices in the other wires running by side is inducing current in the adjacent wire and thus causing interference .
or you mean it is external ie the electric and magnetic field which surround the wire and are capable of inducing current with in the twisted pair ? but one minute isn't the twisted pair shielded ??
Think of you looking at a friend that is using a torchlight to tell you something with Morse Code, at night it works at a reasonable distance.
But at day? He has to be pretty close or you don't see if his torchlight is on or off, as there is so much light around already (from the sun).
Problem is that that effect happens even with electromagnetic radiation. Radio waves, microwaves for the cellphones, stuff from satellites, the wifi of the neighbor all cause some interference. It's not a lot, but if your cable is long enough it is going to catch so much of this interference that no message can get through.
see we have phone but we don't face that case though a lot of wireless communication devices are used ! what is the matter ?
Which is where the coaxial cable kicks in. In it the cable is "shielded". That is it has a metal mesh inside its plastic coating. That is a
Faraday cage, that stops all such interference from reaching the cable inside.
Physics being what it is, electron movement is fast, but not enough for our needs.
The more pulses you can fit per second the more information you can transmit per second. Just like with Morse Code.
And here is where fiber optic cable kicks in. In a fiber optic cable there is no electron movement. The pulses traveling through are made of light.
Light (or any electromagnetic radiation) is officially the fastest thing of the universe, beating everything else by a BIG margin.
look there is a difference between electron and photon .. light is photons and earlier we agreed that data are sent and received by means of electric pulses ie electrons ... so what ?
Which means you can send A LOT of pulses per second (so A LOT of information per second), much more pulses than a metal wire could ever carry. A much higher frequency of pulses.
At the moment, the fiber optic's main slowdown is the devices coding-decoding the signals. As they are of course electronics, so working with a far slower data transfer speed.
that is if my query Is cleared that the data is distributed and manipulated by means of electrons not photons .
