Sampling Theorem

In order for a band-limited (i.e., one with a zero power spectrum for frequencies ) baseband () signal to be reconstructed fully, it must be sampled at a rate . A signal sampled at  is said to be Nyquist sampled, and  is called the Nyquist frequency. No information is lost if a signal is sampled at the Nyquist frequency, and no additional information is gained by sampling faster than this rate.