Editing Node-to-node data transfer (section)

==Modulation==
{{main|Modulation}}

'''Modulation''' is the process of varying a ''[[carrier signal]]'', typically a [[sine wave]] to use that signal to convey [[information]]. One of the three key characteristics of a signal are usually modulated: its [[phase (waves)|phase]], [[frequency]] or [[amplitude]].

In [[Digital data|digital]] modulation, the changes in the signal are chosen from a fixed list (the '''modulation alphabet''') each entry of which conveys a different possible piece of information (a symbol). In [[analog signal|analogue]] modulation, the change is applied continuously in response to the data signal.

Modulation is generally performed to overcome signal transmission issues such as to allow
* Easy (low loss, low dispersion) [[Wave propagation|propagation]] as [[electromagnetic wave]]s
* [[Multiplexing]], the transmission of multiple data signals in one frequency band, on different [[Carrier signal|carrier]] frequencies.
* Smaller, more [[directional antenna]]s

Carrier signals are usually high frequency electromagnetic waves.

Examples of '''modulation''' include:
*[[amplitude modulation]]
*[[frequency modulation]]
*[[Phase-shift keying]]