# Discrete signal

A discrete signal is a signal that has been sampled from a continuous signal. Unlike a continuous signal, a discrete signal is not a continuous function but a sequence. Each value in the sequence is called a sample.

Since a discrete signal is a sequence of samples, the sampling rate must be stored separately (implicitly or explicitly) since the sampling rate cannot be extracted from the samples. This ambiguity is the basis for the establishment of the Shannon-Nyquist sampling theorem. This ambiguity also leads to problems in digital frequency.

## Digital signals

A digital signal and a discrete signal are not the same thing. A digital signal is a discrete signal that has been quantized. In other words, a discrete signal has values with infinite precision while a digital signal has values with finite precision (8 bit, 16 bit, 32 bit, etc.).

## Digital control

Digital control is a digital system that uses discrete signals for use in control systems.

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