Continuous time
Continuous time occurs when time is sampled continuously. In electrical signals, it is sometimes used interchangeably with analog.
In analog signals, a signal is normally expressed as a function of the continuous-time variable t (e.g., x(t)). Analysis of continuous-time systems often makes use of the Laplace transform.
Usage: when the phrase "continuous time" is used as a noun it should not by hyphenated; when it is a compound adjective, as when one writes of a "continuous-time controller", then, at least according to traditional punctuation rules, it should be hyphenated. See hyphen for more.