P7.25 Solid-state integrated electronic circuits are com

posed of distributed R and C elements. Therefore, feedback electronic circuits in integrated circuit form must be investigated by obtaining the transfer func

tion of the distributed RC networks. It has been shown that the slope of the attenuation curve of a distributed

RC network is 10n dB/decade, where n is the order of the RC filter [13]. This attenuation is in contrast with the normal 20n dB/decade for the lumped parameter circuits. An interesting case arises when the distrib

uted RC network occurs in a series-to-shunt feedback path of a transistor amplifier. Then the loop transfer function may be written as

L(s) = Ge(s)G(s) = K(s1)(s+3)1/2 (s+1)(s+2)/2 (a) Using the root locus method, determine the locus of roots as K varies from zero to infinity. (b) Calculate the gain at borderline stability and the frequency of oscillation for this gain.