avoid confusion, perhaps the best thing to do is to refer to it as the sampling theorem, "rather than trying to find a title that does justice to all claimants" [136]. Why Nyquist? Exactly how, when, or why Harry Nyquist had his name attached to the sampling theorem remains obscure. The term Nyquist Sampling Theorem (capitalized thus) appeared as early as 1959 in a book from his former employer, Bell Labs, and appeared again in 1963, and not capitalized in 1965. It had been called the Shannon Sampling Theorem as early as 1954, but also just the sampling theorem by several other books in the early 1950s. In 1958, Blackman and Tukey cited Nyquist's 1928 article as a reference for the sampling theorem of information theory, even though that article does not treat sampling and reconstruction of continuous signals as others did. Their glossary of terms includes these entries: Sampling theorem (of information theory) Nyquist's result that equi-spaced data, with two or more points per cycle of highest frequency, allows reconstruction of band-limited functions. (See Cardinal theorem.) Cardinal theorem (of interpolation theory) A precise statement of the conditions under which values given at a doubly infinite set of equally spaced points can be interpolated to yield a continuous band-limited function with the aid of the function Exactly what "Nyquist's result" they are referring to remains mysterious. When Shannon stated and proved the sampling theorem in his 1949 article, according to Meijering, "he referred to the critical sampling interval as the Nyquist interval corresponding to the band W, in recognition of Nyquist’s discovery of the fundamental importance of this interval in connection with telegraphy". This explains Nyquist's name on the critical interval, but not on the theorem. Similarly, Nyquist's name was attached to Nyquist rate in 1953 by Harold S. Black: According to the OED, this may be the origin of the term Nyquist rate. In Black's usage, it is not a sampling rate, but a signaling rate. See also 44,100 Hz, a customary rate used to sample audible frequencies is based on the limits of human hearing and the sampling theorem Balian–Low theorem, a similar theoretical lower bound on sampling rates, but which applies to time–frequency transforms Cheung–Marks theorem, which specifies conditions where restoration of a signal by the sampling theorem can become ill-posed Shannon–Hartley theorem Nyquist ISI criterion Reconstruction from zero crossings Zero-order hold Dirac comb Notes References Further