Athanasios Papoulis introduced an extension of this theorem involving linear shift-invariant systems, and the Raabe condition associated with it concerns the criterion for unambiguous representation. 
Athanasios Papoulis introduced an extension of this theorem involving linear shift-invariant systems, and the Raabe condition associated with it concerns the criterion for unambiguous representation. This theorem gives a value that is necessary in order to recover all Fourier components of a periodic waveform, or else distortion known as aliasing can occur. Its proof often uses the Dirac comb, and it can be used to reconstruct a signal via a sinc interpolation function. For 10 points, name this theorem, sometimes named for Whittaker and Kotelnikov, that states a band-limited signal may be fully reconstructed if it is sampled at a frequency at least twice the signal bandwidth.
Athanasios Papoulis introduced an extension of this theorem involving linear shift-invariant systems, and the Raabe condition associated with it concerns the criterion for unambiguous representation.