Analog Signal is a continuous sine wave in which one time-varying quantity (such as voltage, pressure, etc.) represents another time-based variable. In other words, one variable is an analog of the other. The result is that Analog systems allow for a theoretically infinite number of values to be represented: it can achieve any value within the parameters governing the system. Analog signal can be utilized in analog devices exclusively, thermometer.
The best examples of analog signals are video, human voice in the air, radio transmission waves, or TV transmission waves.