How Radio Waves Transmit Data?
Wireless technologies are now everywhere around us. But how does it really work? I will review different types of modulation and signal transmission modes, from the simplest to the most complicated.
Let’s try to figure out, without formulas and as simply as possible, how we can transfer data from point “A” to point “B”.
OOK (On-Off Keying)
The simplest form of digital coding. Just turn on / off the radio transmitter in accordance with the binary signal:
On the spectrum, such a signal looks something like this, there are quite a few of them at ~ 434 MHz frequency:
The transmitter circuitry is very simple, therefore it is actively used in wireless remotes, radio-controlled buttons and other similar $ 1–2 devices. There is usually no encryption, the frequency and bit sequence are hard-coded, anyone can transmit and receive this signal. I would not put such a remote control on the garage door where the Lamborghini is kept, but for a bedside lamp…
