Nyquistn.
/ˈnʌɪkwɪst/, U.S. /ˈnaɪˌkwɪst/ Engineering, Electronics, and Mathematics.
1. attributive and in the genitive. Designating various methods, concepts, etc., arising from the work of Nyquist, esp. in the mathematical treatment of feedback, noise, and sampling accuracy.
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1934 Proc. IRE 22 1198 Application of the Nyquist stability criterion requires the determination of the vector transfer constant around the feedback loop at all frequencies.
1948 E. Durand in R. V. Pound Microwave Mixers vii. 296 Such a circuit is essentially an inverse feedback loop, and therefore, the Nyquist theorem applies.
1960 Proc. Royal Soc. A. 259 82 We wish to calculate the scattering from the random thermal density fluctuations in a collisionless plasma, and to do this we shall make use of a generalized version of Nyquist's noise theorem.
1991 G. H. Tomlinson Electr. Networks & Filters 249 The loop frequency response function can be plotted in polar form in the complex plane known as the Nyquist plane.
2. Nyquist criterion n. (also Nyquist's criterion) .
a. A principle for determining the stability or instability of a feedback system according to whether the plot of a Nyquist diagram encircles the point (−1, 0) or not. More fully Nyquist (also Nyquist's) stability criterion.
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1934 [see sense 1].
1945 L. A. McColl Fund. Theory Servomechanisms v. 27 If this number is other than zero, the equation does have roots in the right-hand half-plane, and the system is unstable. This is Nyquist's criterion.
1952 Econometrica 20 269 A modification of the Nyquist stability criterion is provided for the investigation of stability of oscillation.
1984 SIAM Rev. 26 496 A notable example of the importance of complex function theory is the Nyquist criterion for the stability of feedback amplifiers.
1987 A. K. Walton Network Anal. & Pract. (BNC) x. 245 The critical condition regarding stability is embodied in Nyquist's criterion.
b. A criterion for the accurate sampling or digitization of data, requiring the frequency of sampling to be twice the maximum frequency of the data (cf. Nyquist frequency n. at sense 4b).
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1978 Philos. Trans. (Royal Soc.) A. 290 295 The sampling interval is just a quarter of the periodic wavelength and therefore well within the Nyquist criterion of two samples per period.
1987 Proc. Royal Soc. B. 230 284 The Nyquist criterion for separating sampling points in an array, i.e. there must be fields which fall between the objects as well as those which respond.
1999 Proc. National Acad. Sci. U.S.A. 96 6758/2 We examined the early stages of ZP3 signal transduction..by using a detector system with a temporal resolution, as estimated by Nyquist's criterion, of 2–4 msec.
3. Nyquist diagram n. (also Nyquist plot) a representation of the vector response of a feedback system as a complex graphical plot showing the relationship between feedback and gain.
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1947 H. M. James et al. Theory of Servomechanisms ii. 66 The plot of Y (jω) in the complex Y-plane for all real values of ω is called the feedback transfer locus; it is also referred to as the Nyquist diagram of the transfer function.
1952 Econometrica 20 280 (caption) Nyquist plot of quasi-linear representation of Goodwin's model.
1967 Statistician 17 174 In general, the quadrant in which a Nyquist plot converges to the origin is an indication of the order of the system.
1987 J. Millman & A. Grabel Microelectronics (ed. 2) xiii. 569 In 1931 Nyquist developed a graphical construction, subsequently named the Nyquist diagram, to determine whether a feedback amplifier had any right-half-plane poles.
4.
a. Nyquist rate n. the minimum rate at which it is necessary to sample a signal or a sequence of data in order that it may be uniquely reconstructed, which is equal to twice the frequency of the highest-frequency component present in the input.
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1953 H. S. Black Modulation Theory v. 65 With high-speed signaling approaching the Nyquist rate (2B elements per second if the band width is B) the code elements will overlap..to produce a..wave.
1990 M. M. Mirabito & B. Morgenstern New Communications Technol. ii. 20/1 It has been determined that if a signal is sampled at a rate that is twice its highest frequency, the analog signal would be accurately represented. This characteristic of the digitization process is called the Nyquist rate.
b. Nyquist frequency n. (also Nyquist limit) the maximum frequency of signal or of data distribution that can be uniquely recovered in a sampled channel without risk of aliasing, equal to half the sampling frequency.
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the world > matter > physics > electromagnetic radiation > electronics > electronic phenomena > [noun] > frequency > specific frequencies
high frequency1842
natural frequency1873
resonant frequency1897
resonance frequency1898
low frequency1928
modulation frequency1930
quench frequency1938
gyrofrequency1941
Nyquist frequency1963
1963 Philos. Trans. (Royal Soc.) A. 255 512 Any oscillations whose frequency exceeds the Nyquist frequency (one-half the sample frequency) will be indistinguishable from some lower frequency. Tukey calls this effect ‘aliasing’.
1976 Nature 25 Nov. 342/2 Because of the finite sampling time..we cannot exclude the possibility that we are observing an alias of a modulation shorter than the Nyquist frequency of the data.
1998 Systematic Biol. 47 313/1 Calls were digitized at a rate of 20 kHz; therefore the Nyquist frequency is 10 kHz, substantially above the highest frequencies in any of the calls analyzed.
This is a new entry (OED Third Edition, March 2004; most recently modified version published online March 2022).
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n.1934