General case for an underdamped second-order system

3 General case for an underdamped second-order system 

For the generalized seeond-order transfer funetion given in equation (3.43), equating the denominator to zero gives the eharaeteristie equation 

as ( is varied from zero to one, point P deseribes an are of a eirele of radius con, eommeneing on the imaginary axis ((3 = 90°) and finishing on the real axis ((3 = 0°). 

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