Definition of Nyquist diagram in English:

Nyquist diagram

(also Nyquist plot)

noun

Electronics
  • A representation of the vector response of a feedback system (especially an amplifier) as a complex graphical plot showing the relationship between feedback and gain.

    • ‘A Nyquist diagram shows the locus of a point on the complex plane.’
    • ‘For these systems, in addition to determining the absolute stability of a system, the Nyquist diagram provides qualitative information as to the degree of stability.’
    • ‘The frequency response of a system can be viewed two different ways: via the Bode plot or via the Nyquist diagram.’

Origin

1930s: see Nyquist criterion.