Analog signals are characterized by being continuous in time and continuous in value. The conversion process of analog signals is often referred to as quantization.

Digital signals, on the other hand, are signals that have undergone a form of quantization process, which means that instead of being continuous signals, they are discrete signals. Digital signals are both time-discrete and value-discrete.

Analog Signals

Analog signals are continuous in time and continuous in value. This means that the signal exists at every moment in time and can take any value within a certain range. There are no jumps or gaps in the signal. Many physical quantities, such as sound, temperature, or light intensity, can naturally be described by analog signals.

Because analog signals change continuously, they provide a direct representation of real-world processes.

Digital Signals

Digital signals, on the other hand, are not continuous. They are signals that have undergone a quantisation process. As a result, digital signals are discrete in time and discrete in value. Instead of being defined at every point in time, a digital signal is only defined at certain time instants. In addition, the signal values are restricted to a finite set of possible values. Digital signals therefore consist of individual values rather than a continuous waveform.