How are bits actually transmitted over a network cable?

Question

Computer networks

Good afternoon!
I am very tormented by a misunderstanding of the following question, please help.
Say plz. The PC creates a sequence of bits to transmit them over twisted pair, these bits go to the network card, where the transceiver converts them into an electrical signal. As I understand it, the transceiver does this due to modulation, but I cannot understand due to which modulation. Is it related to this as an ADC and DAC. And what about the Fourier transform?
Could you explain using a specific example, for example, how to transfer the letter "b" or the bit sequence 01100010 over a twisted pair cable from one PC to another PC, which laws of physics and rules of network technologies are affected.
Thank you in advance

Answer 1

A search first for the phrase "twisted pair", and then for "10BASE-T" led to a wiki , where they write that

signal modulation - phase . One period is allocated for one bit. A change in the phase of oscillations means a change in the logical state from 0 to 1 or vice versa

Those. a sinusoid with a frequency of 10 MHz and an amplitude of +/- 2 Volts “hums” in the wires. The phase sometimes changes. So, if the letter "b" were transmitted directly as 01100010, it would take 8 periods, i.e. 8/10000th of a second, and the phase would change 4 times.

Answer 2

The PC creates a sequence of bits to transmit them over twisted pair, these bits go to the network card, where the transceiver converts them into an electrical signal.

Almost everything is so, only the bits are also an electrical signal. To be precise, the network card converts the electrical signals that encode the data bits in the computer, according to its operation algorithm, into other electrical signals, which are then sent to the physical line. An exception is the case when an optical cable acts as a physical line. Then the electrical signal is converted into an optical one.

The transceiver does this through modulation, but I can't figure out which modulation.

Not modulation, but manipulation: the control is carried out by a discrete signal - these are our bits. To understand, you need to remember the school physics course and the formula
A = E * sin(ω * t)
Everything works on the control of the manipulating signal by one or another argument / arguments of this function.

Does this have something to do with the ADC and DAC?

No way. manipulate the phase (product ω * t) of the sinusoid.

And what about the Fourier transform?

Yes, he often gets nuts with or without reason. Working with frequency response, phase response and group delay is more needed at the design stage of a twisted pair. And it was logical then to add Pistohlkors with his theory of standing, traveling and mixed waves. A standing wave or a good reflection on the transmitter from a twisted pair can sharpen the picture much more than a distorted signal spectrum.

Could you explain using a specific example, for example, how to transfer the letter "b" or the bit sequence 01100010 over a twisted pair cable from one PC to another PC, which laws of physics and rules of network technologies are affected.

Better read the article . Everything is quite intelligibly explained on colored pieces of paper.