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Discrete-Time Signals
A discrete-time signal is a sequence of values that correspond to particular instants in time. The time instants at which the signal is defined are called the signal's sample times; traditionally, a discrete-time signal is considered to be undefined at points in time between these instants. For a periodically sampled signal, the equal interval between any pair of sample times is the signal's sample period, Ts. The sample rate, Fs, is the reciprocal of the sample period, or 1/Ts.
For example, the 7.5-second triangle wave segment below has a sample period of 0.5 seconds, and sample times of 0.0, 0.5, 1.0, 1.5, ...,7.5. The sample rate of the sequence is therefore 1/0.5, or 2 Hz.
The following sections provide definitions for a number of terms commonly used to describe the time and frequency characteristics of discrete-time signals, and explain how these characteristics relate to Simulink models:
![]() | Signal Concepts | Time and Frequency Terminology | ![]() |