Sampling

In digital signal processing, sampling is the act of taking a continuous signal and reducing it to a discrete signal. A sample is a single value of the discrete signal. How fast the samples are taken is the sampling rate.

Sampling can be thought of as the act of discretizing the x-axis.

Here is an example of a cosine wave with a frequency of 50 Hz made into a discrete signal using a sampling rate of 1000 samples per second.