Physics – 3.3 Electromagnetic spectrum | e-Consult

An analogue signal is a continuous electrical signal that varies in amplitude and/or frequency in proportion to the sound wave it represents. It is a smooth, varying waveform. A digital signal, on the other hand, is a discrete signal that represents information using a sequence of 0s and 1s (binary code). It consists of distinct, separate levels.

A microphone produces an analogue signal because sound waves are continuous variations in air pressure. The microphone needs to accurately represent these continuous variations in pressure as a corresponding continuous variation in electrical potential. An analogue signal allows for this direct, proportional representation. Converting sound to a digital signal requires a process called sampling and quantization, which involves discretizing the continuous sound wave, potentially losing some information. While digital signals have advantages in terms of noise immunity and storage, the initial conversion from sound to electrical signal is naturally analogue.