Steady-state methods have been devised to compute periodic wave-forms without having to integrate the autonomous circuit equations until the transients die out. Stability analysis of the computed solutions is the next topic to be addressed by a steady state circuit simulator. Shooting methods based on Newton's iteration are expensive in terms of computing time, because each iteration step requires integration of the variational equation, but directly provide information on the stability of the final On the other hand, when making use of harmonic balance methods, the stability of the computed solutions is typically investigated from a continuation point of view.4 Recently a discrete time approach (DTA) was proposed for the analysis and optimization of non-linear autonomous circuits.' This letter describes how the stability of the computed periodic wave-forms may be easily determined (I posteriori with no modification to the DTA solution method.