There are many analog systems. Watch hands are analogous to the earth's rotation. Analog telephones turn air waves into analogous electrical waves.
In traditional radio, the original sound waves are maintained as analogous electrical waves throughout the entire chain from recording microphone to the listener's speakers. The analog waves are transmitted over the air in the radio station's channel frequency, which is called a "carrier." The carrier is altered (modulated) to contain the analog waves as if wrapped within conceptually.
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