H Nyquist 1932 frequency-domain stability: Nyquist plot encirclements of -1 = number of unstable poles in closed-loop; Bode 1945 extends with phase-margin + gain-margin design rules.
H Nyquist 1932 frequency-domain stability: Nyquist plot encirclements of -1 = number of unstable poles in closed-loop; Bode 1945 extends with phase-margin + gain-margin design rules.