Digital samples

In digital signal processing, a sample refers to the value attained by an analog signal acquired at regular intervals when digitising it.

The Nyquist-Shannon sampling theorem dictates that this should occur at not less than twice the highest frequency in the sampled waveform. Typically, an analog anti-aliasing filter is applied before sampling to ensure that this is the case. If frequencies higher than half the sampling frequency remain, aliasing will occur, with these frequencies being wrapped around into frequencies within the sampled frequency range.

See also: Signal processing