Analog vs Digital
The first thing you need to understand is that there are two types of radio signals—analog and digital.
Analog signals use a continuous waveform called an “amplitude modulated” signal.
Digital signals are made up of individual 1s and 0s (called binary digits) that are sent as pulses.
These pulses are then converted into an analog signal by using a receiver or transceiver device.
Note that this is not the same as digital cellular.