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The Nyquist plot for () = + + with s = jω.. In control theory and stability theory, the Nyquist stability criterion or Strecker–Nyquist stability criterion, independently discovered by the German electrical engineer Felix Strecker [] at Siemens in 1930 [1] [2] [3] and the Swedish-American electrical engineer Harry Nyquist at Bell Telephone Laboratories in 1932, [4] is a graphical technique ...
Liénard–Chipart criterion; Nyquist stability criterion; Routh–Hurwitz stability criterion; Vakhitov–Kolokolov stability criterion; Barkhausen stability criterion; Stability may also be determined by means of root locus analysis. Although the concept of stability is general, there are several narrower definitions through which it may be ...
The Nyquist stability criterion developed by Harry Nyquist of Bell Laboratories is used to study the stability of feedback amplifiers. Feedback amplifiers share these properties: [3] Pros: Can increase or decrease input impedance (depending on type of feedback). Can increase or decrease output impedance (depending on type of feedback).
[1]: 209 Ashby saw this law as relevant to problems in biology such as homeostasis, and a "wealth of possible applications". Later, in 1970, Conant working with Ashby produced the good regulator theorem [ 7 ] which required autonomous systems to acquire an internal model of their environment to persist and achieve stability (e.g. Nyquist ...
Two mathematical tests that can be used to diagnose such an instability are the Routh–Hurwitz and Nyquist criteria. The amplitude of the oscillation of an unstable system grows exponentially with time (i.e., small oscillations are negatively damped), until nonlinearities become important and limit the amplitude.
Nyquist criterion may refer to: Nyquist stability criterion, a graphical technique for determining the stability of a feedback control system; Nyquist frequency, ½ of the sampling rate of a discrete signal processing system; Nyquist rate, a rate used in signal processing; Nyquist ISI criterion, a condition to avoid intersymbol interference
Directional stability, the tendency for a body moving with respect to a medium to point in the direction of motion; Elastic stability, the resistance of a structural member to buckling; Flight dynamics, including longitudinal stability; Nyquist stability criterion, defining the limits of stability for pole-zero analysis in control systems
Harry Nyquist at Bell Labs derived the Nyquist stability criterion for determining the stability of feedback systems. An easier method, but less general, is to use Bode plots developed by Hendrik Bode to determine the gain margin and phase margin .