Nyquist Criterion

Nyquist Criterion

 

(named after the American physicist H. Nyquist), a frequency criterion for the stability of linear automatic control systems with constant parameters. This criterion can also be applied to time lag systems.

References in periodicals archive ?
The stability can be analysed by Nyquist criterion. In order to overcome the conservatism and forbidden region of the improved current source criterion, the following two points are mainly considered.
But if somehow we can overcome a Shannon Nyquist criterion that is if we can reconstruct original signal by using very less number of samples as compared to the Nyquist criteria, then problem of storage and processing of large data can be solved.
Key words: time delay systems, argument principle, distributed delays, Nyquist criterion
This restriction, the Nyquist criterion, must be observed to allow reconstruction of the original waveform without aliasing.
In terms of that figure, the Nyquist criterion for a normalized FSK phase trajectory q(t) is
If samples are taken and stored at a rate that is at least twice that of the information bandwidth of the radar signal (the Nyquist criterion), the signal can be coherently reconstructed at a later time without the loss of any information, including coherence.
A good rule is to use the Nyquist criterion, which basically says that one should collect two points per resolution size (Inoue and Spring, 1997, p.
An accurate method for checking the stability of a circuit is to consider the Nyquist criterion, which overcomes the limitations of the traditional methods described previously.
If samples are taken and stored at a rate that is at least twice that of the information bandwidth of the radar signal (the Nyquist criterion) then the signal can be coherently reconstructed at some later time without the loss of any information, including coherence.
The factor of 2 satisfies the Nyquist criterion, and the ratio 0.5/0.4 accounts for the excess bandwidth required by the filter's transition region.
(It will be demonstrated later in this article that this configuration allows for the simplification of the Nyquist criterion).