An analog signal is characterized by continuous variations in both time and amplitude (signal strength). The temporal changes are typically expressed in terms of the signal’s frequency (tones) or the frequencies it comprises, measured in Hertz (Hz), which denotes cycles per second.

An example of an analog signal is an electrical signal generated by a microphone.

In contrast, a digital signal is discrete in both time and amplitude. To convert an analog signal into a digital one, an Analog-Digital Converter (ADC) is required.

The term ‘analog’ also extends to refer to devices or circuits designed to process analog signals. In such cases, the output of an analog device exhibits continuous variation in response to the input signal.

It’s worth noting that the first generation of mobile communication systems (1G) utilized analog technology.