AfterDawn: Glossary

The Nyquist-Shannon Sampling Theorem used as the basis for all analog capturing requires a sampling Frequency equal to slightly more than twice the frequency of the analog signal. In other words, to accurately Sample 20kHz (20,000Hz) audio you need a sampling frequency of at least 40.1kHz (20,000 x 2 + 1). Oversampling refers to sampling at a higher frequency than the Nyquist Frequency.

Although in theory Oversampling isn't necessary, in reality consumer equipment isn't capable of the precision required by the Sampling Theorem. By taking additional samples, accuracy is improved, resulting in a digital sound or image closer to the original.