Analog signal (English) refers to a signal whose mathematical form is a time-domain continuous function. Corresponding to analog signals are digital signals, which take discrete logical values, while the former can get continuous values. The concept of analog signal is often used in the field of electricity, but it is sometimes used in classical mechanics, aerodynamics, hydraulics and other disciplines.
Analog signals use some physical characteristics of objects to express and transmit information. For example, a non-liquid barometer uses the spiral position of a pointer to represent pressure information. In electricity, voltage is the most common physical medium for analog signals. In addition, frequency, current and charge can also be used to represent analog signals.
Any information can be expressed by analog signals. The signal here usually refers to the measured response to the change of physical phenomena, such as sound, light, temperature, displacement and pressure, which can be measured by sensors. In analog signals, the signal values at different time points can change continuously; For digital signals, the signal values at different time points are always at preset discrete points, so if the real values of physical quantities cannot be found in these preset values, then the digital signal has a certain deviation from the real values.