SampleTime

SampleTime is the time interval between successive samples of a continuous signal when it is converted to discrete time. It defines how often data is captured or processed in a digital system and is the reciprocal of the sampling frequency Fs (Fs = 1 / SampleTime).

In digital signal processing and control theory, the choice of SampleTime affects fidelity, processing load, and stability. A shorter SampleTime yields higher temporal resolution and better representation of fast-changing signals but increases data rate and computational requirements. A longer SampleTime reduces resolution and may introduce aliasing or discretization error if it does not capture the signal’s bandwidth adequately. The Nyquist criterion guides the minimum sampling rate needed to avoid aliasing for a given maximum signal frequency.

In modeling and simulation environments, SampleTime is a configurable parameter. In some tools such as MATLAB/Simulink, discrete components specify a positive, fixed sample time, continuous-time components use a sample time of 0, and components can inherit a sample time (-1) from their parent system. The exact interpretation can vary by platform, so documentation should be consulted for specifics.

Practical guidelines include assessing the signal bandwidth, choosing a Ts that is no larger than about 1/(2·Fmax), and considering real-time constraints. For hardware implementations, the SampleTime corresponds to the ADC sampling rate and the software loop update rate. In non-real-time simulations, variable-step solvers may adjust the effective sample time, while fixed-step simulations enforce a constant SampleTime throughout.