Nyquist-Shannon Sampling Theorem
A sampling result stating that a band-limited signal can be reconstructed from samples taken above twice its highest frequency under ideal conditions.
Sampling Context
The Nyquist-Shannon sampling theorem states that a band-limited continuous signal can be reconstructed from uniform samples when the sampling rate is greater than twice its highest frequency. Real acquisition systems cannot implement an ideal brick-wall filter, so they normally reserve a guard band below the theoretical limit and use an anti-aliasing filter.
Measurement Boundary
The theorem addresses temporal sampling sufficiency; it does not eliminate quantization noise, clock jitter, sensor noise, or finite-filter effects.