Before revision: Iso-damping is a desirable system property referring to a state , where the open-loop phase Bode plot is flat , i.e., the phase derivative with respect to the frequency is zero, at a given frequency called the "tangent frequency", .
After revision: Iso-damping is a desirable system property referring to a state — where the open-loop phase Bode plot is flat i.e., the phase derivative with respect to the frequency is zero, at a given frequency called the "tangent frequency", .