Stability Criteria for Tunnel-Diode Amplifiers (Correspondence)

A tunnel-diode amplifier is stable when the amplifier network is reduced to an arbitrary single loop and the equation given by the sum of the impedances around this loop equal to zero [/spl Sigma/Z(P)=0 where p= /spl gamma/ +j/spl omega/ ] has no solution in the right-half plane (/spl gamma/>0). This is equivalent to the requirement that the system determinant shall have no zeros in the right-half plane. Several authors have used this criterion. To determine analytically whether /spl Sigma/Z(p) has any positive zeros is very laborious if at all possible for many practical amplifier configurations.