analogue transmission

Analogue transmission involves varying a characteristic of a carrier wave in proportion to an information signal. This process, called modulation, is used to adapt signals for transmission over specific channels or to allow multiple users to share a channel without interference.1

Voice, audio, and video signals are inherently analog. While many modern systems digitize these signals, some still transmit them directly. Two common analog modulation techniques are:
* Amplitude Modulation (AM): Varies the amplitude of a fixed-frequency carrier wave.1
* Frequency Modulation (FM): Varies the frequency of a fixed-amplitude carrier wave.1

Analogue signals are continuous and can take on any value within a range. In contrast, digital transmission uses discrete binary values (0s and 1s), which are more resistant to noise and distortion. Historically, long-distance telephone transmission relied on analog systems using frequency-division multiplexing (FDM), but these have largely been replaced by digital systems employing time-division multiplexing (TDM).23