On the usefulness of the SPICE simulation program in the prediction of anomalous behavior in complex nonlinear circuits

Abstract

It i s shown t h a t i n a d d i t i o n t o i t s o b v i o u s merits i n d e m o n s t r a t i n g and c o n f i r m i n g t h e o r e t i c a l l y t r a c t a b l e p r o p e r t i e s of e l e c t r o n i c c i r c u i t s and c i r c u i t models of p h y s i c a l systems, t h e SPICE s i m u l a t i o n program o f t e n , almost by a c c i d e n t , can l e a d t o a s p e c t s of c i r c u i t b e h a v i o r o t h e r w i s e u n f o r e s e e n p r i o r t o t h e s i m u l a t i o n . Two s p e c i f i c examples are t a k e n t o i l l u s t r a t e t h i s f e a t u r e . In t h e f i r s t , i t i s shown how SPICE c o r r e c t l y p r e d i c t e d i n s t a b i l i t y i n a n o n l i n e a r c a p a c i t o r model due t o a p h y s i c a l l y i n c o r r e c t c h o i c e of a -p a r a m e t e r , l a t e r confirmed by a c l o s e r i n v e s t i g a t i o n of t h e t h e o r y . In t h e second, r . f . p u l s e experiments i n a n ensemble of g e n e r a l s i g n a l c h a r a c t e r i s t i c s of anharmonic and n o n l i n e a r l y coupled param e t r i c echoes [ 4 ] . The purpose i s t o show t h a t w h i l e t h e s i m u l a t i o n w a s 88TH0220-4 c o p y r i g h t 1988 IEEE 2 2 0 J