What does Nyquist Theorem state about signal sampling?

The Nyquist Theorem states that in order to accurately reconstruct a signal from its samples, the signal must be sampled at least twice the highest frequency present in that signal. This is a fundamental principle in signal processing, known as the Nyquist Rate. If a signal is sampled below this rate, aliasing can occur, leading to distortion and loss of information in the reconstructed signal. Sampling at just twice the highest frequency ensures that all the necessary information about the signal's amplitude changes is captured adequately to reconstruct the original signal without loss.

This theorem is crucial in various applications, including audio, video, and communications, where maintaining signal integrity is essential. Other choices do not align with the Nyquist Theorem, as they suggest sampling rates that are either insufficient or overly relaxed, which would not allow for proper signal reconstruction.