This Topic is a very brief introduction to the idea of native discrete-time signals, created as sequence of numbers, rather than viewed as a discrete-time representation of an underlying continuous-time signal. Three very simple signals are introduced, such as the unit impulse, unit step, and exponential decay (as well as a decaying cosine or sinusoid). Finally, the video gives a brief overview of creating discrete-time finite-duration signals in MATLAB. The viewer is then asked to consider how to create other signals in MATLAB, for example a sinusoid of a specific frequency.