How do multiple frequencies coexist in one cable?

Question

Mathematics

The question may seem silly, but how in one coaxial cable from a satellite 10 frequencies (channels) are transmitted at once.
It does not give me rest, how several frequencies coexist in it and are simultaneously transmitted.
Are they transmitted in parallel?

Answer 1

If it's very rough, then look at the figure:
Your cable has a signal from the third graph, obtained by adding the signals from the first two graphs.
By passing the third signal through the filter, you can get the original two.
In reality, there can be more than two signals, each of which can be modulated in frequency, amplitude, phase.
However, from one satellite, 10 channels may well go at the same frequency.
Take, for example, a broadcast DVB-T2 signal - at each frequency (frequency band) there are 10 digital channels at once - about the same as you can download 10 torrents from one provider at once.

Answer 2

Multiplexing

Answer 3

I'm not special, but as far as I understand, amplitude or phase modulation is used in such signals.
The information signal itself is not transmitted, but affects the characteristics of the carrier signal, which has a constant frequency but a variable phase or amplitude. It is easy to extract a constant frequency from the total signal, measure its parameters, and use them to restore the original signal.
The summation of several signals with different frequencies does not affect these characteristics of the individual signals.

Answer 4

It does not give me rest, how several frequencies coexist in it and are simultaneously transmitted.
And how do many frequencies coexist simultaneously in the atmosphere does not bother you?
And in satellite communication channels, most likely, conditionally, there is one frequency with code division of channels. (well, different frequencies are also used, but television can be broadcast on the same frequency with channel separation)

Answer 5

um... we take some kind of multiband equalizer, turn on the music and bring all the knobs to the very bottom, and one of the lowest frequencies - up. As a result, we hear only boom-boom. Then we also output only the highest frequency - we hear pss-pss, then we output the knob in the region of 1-3 kHz - we hear the voices of singers
Here is the simplest illustration of frequency filtering: from a bunch of different frequencies - select one thing.
Or as another option: we make the music louder and put the tuning fork next to the speakers - it will vibrate (resonate) in time with the presence of the note la of the first octave, if one occurs in the music.
We put another, exotic tuning fork next to it on D of the second octave - it will ring to the corresponding notes.
If now we ask one musician to "morse" on the first octave la, and the second on the second octave - then with these two tuning forks you can separate one morse code from another.