Discrete-time signal

Discrete sampled signal

"Discrete signal" redirects here and is not to be confused with Digital signal.

A discrete signal or discrete-time signal is a time series consisting of a sequence of quantities. In other words, it is a time series that is a function over a domain of integers.

Unlike a continuous-time signal, a discrete-time signal is not a function of a continuous argument; however, it may have been obtained by sampling from a continuous-time signal, and then each value in the sequence is called a sample. When a discrete-time signal obtained by sampling a sequence corresponds to uniformly spaced times, it has an associated sampling rate; the sampling rate is not apparent in the data sequence, and so needs to be associated as a characteristic unit of the system.

Acquisition

Discrete signals may have several origins, but can usually be classified into one of two groups:

• By acquiring values of an analog signal at constant or variable rate. This process is called sampling.
• By recording the number of events of a given kind over finite time periods. For example, this could be the number of people taking a certain elevator every day.

See also

• Aliasing
• Anti-aliasing filter
• Bernoulli process
• Digital
• Digital-to-analog converter
• Digital control
• Normalized frequency
• Discrete system
• Nyquist frequency
• Nyquist–Shannon sampling theorem
• Whittaker–Shannon interpolation formula
• Sampling (signal processing)

References

• Gershenfeld, Neil A. (1999). The Nature of mathematical Modeling. Cambridge University Press. ISBN 0-521-57095-6.

• Wagner, Thomas Charles Gordon (1959). Analytical transients. Wiley.